FM 640 1984 OBSOLETE Field Artillery Cannon Gunnery

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6.35

ARTILLERYCANNON

GUNNERY

HEADQUARTERSDEPARTMENTOF THE ARMY

FM 6-40

EGRADED "APPROVED FOR PUBLIC

ELEASE". SEE LAST TWO PAGES OF

HIS PDF.



Field ManualNo. 6-40

*FM 6-40HEADQUARTERS

DEPARTMENT OF THE ARMYWashington, DC, 7 December 1984

FIELD ARTILLERY CANNON GUNNERY

Table of Contents

PREFACE

CHAPTER 1.

CHAPTER 2.

CHAPTER 3.

Section I.

Section II.

GUNNERY TEAM

1-1 Observer1-2 Fire Direction Center1-3 Firing Battery1-4 Communications Links

GUNNERY PROBLEM

2-1 Gunnery ProblemSolution

2-2 Requirements forAccurate Predicted Fire_

BALLISTICS

Interior Ballistics

3-1 Description3-2 Factors Affecting

Muzzle Velocity3-3 MuzZle Velocity

Measurement

Exterior Ballistics

3-4 Description 3-53-5 Trajectory Elements 3-5

3-6 Round-to-RoundVariations 3-7

3-7 Dispersion Rectangles 3-73-8 Range Probable Error 3-83-9 Deflection Probable

Error_3-93-10 Vertical Probable

Error_3-103-11 Height-of-Burst

Probable Error 3-10

*This publication supersedes FM 6-40, 1 December 1978. In addition, this publication rescinds DA Form

4207, October 1978.

Page

1-11-1

1-21-2

2-1

2-1

3-1

3-1

3-3

3-4

3-5^. r-



CHAPTER 4.

CHAPTER 5.

Section I.

Section II.

Section III.

CHAPTER 6.

Section I.

FIRE DIRECTION CENTEROPERATIONS

4-1 BCS/Manual FDC_4-2 FADAC/Manual FDC

4-3 Manual FDC4-4 Battalion FDC4-5 3x8 Operations4-6 Firing Data Checks

SURVEYED FIRING CHARTS

Types of Surveyed FiringCharts

5-1 Description5-2 Construction of Firing

Charts

Plotting Equipment and Preparationof Firing Charts

5-3 Chart Operation5-4 Equipment5-5 Point Plotting5-6 Tick Marks5-7 Construction of

Azimuth Indexes5-8 Construction of

Deflection Indexes

5-9 6,400-Mil Charts5-10 Methods Used in

Plotting Targets

Chart Data

5-11 Chart Range andChart Deflection

5-12 AngleT5-13 Subsequent

Corrections5-14 Manual-to-Computer

or Chart-to-Chart Checks_FIRE ORDER/FIRE COMMANDS/MESSAGE TO OBSERVER

Fire order6-1 Definition__________6-2 Considerations in

Attacking a Target6-3 Fire Order Elements_____6-4 Issuing the Fire Order_____

FM 6-40

Page

4-14-34-5

4-64-7

4-8

5-1

5-1

5-2

5-2

5-25-25-55-8

5-10

5-12

5-15

5-16

5-18

5-185-18

5-19

5-19

6-1

6-1

6-16-26-3



Section II.

Section III.

CHAPTER 7.

Section I.

Section II.

Section III.

Section IV.

6-5 Battalion Fire Orders

6-6 Battery-Level FireOrders

Fire Commands

6-7 Definition

6-8 Fire CommandElements

6-9 Standing OperatingProcedures

6-10 Other Fire Commands6-11 Reports6-12 Repetition and Correction

of Fire Commands

Message to Observer

6-13 Definition

6-14 Additional Information

FIRING TABLES

Graphical Firing Tables

7-1 Means of DeterminingFiring Data

7-2 Description and Use ofthe Low-Angle GFT

7-3 Construction of GFTSettings

7-4 Determination of FiringData by Use of the GFTSetting

Graphical Firing Table Fan

7-5 Description7-6 Construction of a GFT

Setting on a GFT Fan

7-7 Determination of FiringData With the GFT Fan

Tabular Firing Tables

7-8 Standards

7-9 Elements and Purposeof the TFT

Graphical Site Ta b l e s _ _ _ _ _ _ _ _

7-10 Description

7-11 Determination of VerticalInterval

FM 6-40

Page

6-4

6-4

6-6

6-6

6-7

6-86-86-9

6-9

6-9

6-96-14

7-1

7-1

7-1

7-3

7-4

7-7

7-7

7-7

7-8

7-8

7-8

7-9

7-9

7-9

7-11

iii



FM 6-40

Page

7-12 Computations With theGST 7-11

7-13 Determination of Angle of Siteand Vertical Angle Withouta GST_7-13

7-14 Determination of VerticalInterval Without a GST _ 7-13

7-15 Determination of ComplementaryAngle of Site Withouta GST_7-13

7-16 Determination of SiteWithout a GST 7-14

7-17 Average Site 7-14

CHAPTER 8. REPLOT DATA

Section I. Manual Procedures_8-28-1 Point-Detonating and

Variable Time Fuze(M728) Replot 8-2

8-2 Variable Time Fuze(M513/M514) Replot 8-5

8-3 Mechanical Time FuzeReplot 8-6

Section I1. Computer Procedures 8-8

8-4 FADAC Replot 8-8

8-5 Battery ComputerSystem Replot 8-8

CHAPTER 9. FIRING DATA PROCEDURESSection I. High-Explosive Munitions 9-3

9-1 Characteristics9-39-2 Computations for High-

Explosive Projectiles 9-3

9-3 Sample Mission 9-49-4 APICM Projectiles 9-6

9-5 Smoke Projectiles 9-99-6 Illuminating

Projectiles 9-139-7 Illuminating Projectile

Manual Procedures ______ 9-14Section II. Dual-Purpose Improved Conventional

M u n i t i o n s _ _ _ _ _ _ _ _ _ _ _ _ _ 9-18

9-8 Characteristics________ 9-189-9 DPICM Projectiles 9-18

iv



FM 6-40

Page

9-10 DPICM Computations by Useof the GFT and TFT 9-18

9-11 Computer Proceduresfor DPICM 9-21

9-12 FASCAM Projectiles 9-219-13 FASCAM Employment 9-22

9-14 FASCAM Computations 9-22

9-15 Aimpoint Selection

Tables 9-24

9-16 Location of Aimpoints 9-28

9-17 Number of Projectilesper Aimpoint 9-28

9-18 Manual DataDetermination 9-29

9-19 M825 Projectile 9-31

9-20 M825 Computation by Use ofthe GFT and TFT 9-31

Section III. Rocket-Assisted Munitions 9-35

9-21 Characteristics 9-35.9-22 Manual Computation 9-36

9-23 Registration and Determinationof the GFT Setting 9-38

Section IV. Nuclear Munitions 9-38

9-24 Characteristics- 9-38

9-25 M753 Delivery Techniques 9-39

9-26 Manual Data forK-Transfer Technique(M753) 9-39

9-27 Met + VE Technique 9-43

9-28 Observer AdjustmentTechnique 9-45

9-29 M422A1 DeliveryTechnique 9-46

9-30 M422A1 Computer

Procedures 9-489-31 155-mm Howitzer Nuclear

Gunnery 9-509-32 155-mm Nuclear Delivery

Techniques 9-50

9-33 Manual Procedures for ShellNuclear by Use of the GETand TET _________ 9-50

9-34 Nuclear Fire MissionProcessing 9-51

V



FM 6-40

PageSection V. Copperhead 9-52

9-35 Characteristics- 9-529-36 Computations for Shell

Copperhead 9-54

9-37 Mission Priority 9-559-38 Copperhead SOP 9-559-39 Voice Calls for Fire 9-559-40 Message to Observer

(Autonomous) 9-569-41 Laser Pulse Repetition

Frequency Code 9-569-42 Fire Order 9-569-43 Computation of Firing Data 9-569-44 Angle T and Target Cloud

Height Check 9-579-45 Determination of the Range

Offset Correction 9-589-46 Trajectories 9-599-47 Description of M712

Low-Angle Ballistic GFT_ 9-609-48 Low-Angle Ballistic

GFT Setting 9-609-49 Transfer Limits 9-629-50 Application of the GFT

Setting 9-629-51 Data Read From the

Low-Angle Ballistic GFT_____ 9-639-52 M712 Low-Angle Glide

Mode GFT 9-649-53 Determination of the Time

Setting 9-649-54 Determination of Elevation,

Time of Flight, and DesignateTime_9-65

9-55 Glide Mode TransferLimits_9-65

9-56 Glide Mode GFT Setting 9-659-57 Switch Setting 9-679-58 Computation of Site 9-679-59 Computation ofDeflection Correction______ 9-689-60 Computation of FADAC Data 9-689-61 Limits of the Battery

Center Solut ion________ 9-68

9-62 Target AttackContingencies 9-68

vi



Record of FireFire CommandsEngagement CommandsHigh-Angle Fire

High-Angle GFTHigh-Angle GFT Settings

Data ComputationExample of a High-AngleMission

CHAPTER 10.

Section I.

Section I1.

Section III.

Section IV.

Section V.

METEOROLOGICAL CORRECTIONSAND VELOCITY ERROR

Purpose and Use of Met Messages

10-1 Nonstandard Conditions

10-2 Concurrent Met10-3 Subsequent Met

10-4 Velocity Error

Met Messages

10-5 Characteristics

10-6 Ballistic Met Message10-7 Computer Met Message10-8 Met Message Errors10-9 Met Message Space and

and Time Validity

Concurrent Met

10-10 Characteristics

10-11 Sequence for Solution of aa Concurrent Met

10-12 Solution of a ConcurrentMet

10-13 Position Constants

10-110-110-210-210-3

10-3

10-310-310-610-8

10-9

10-1010-10

10-10

10-1110-30

Subsequent Met 10-32

10-14 Characteristics 10-32

10-15 Sequence for Solution ofa Subsequent Met 10-32

10-16 Solution of a SubsequentMet_10-33

Subsequent Met Applications 10-35

10-17 Eight-Direction Met 10-35

10-18 Met to a Met CheckGage Point 10-38

10-19 Met to a Target 10-38

vii

FM 6-40

9-639-649-659-66

9-679-689-699-70

Page9-689-709-719-719-72

9-739-74

9-76



Section VI.

CHAPTER 11.

CHAPTER 12.

Section I.

Section II.

Section III.

Met Plus Velocity Error

10-20 Application of VelocityError

10-21 Manual Computation of aGFT Setting for an UnregisteredCharge

MUZZLE VELOCITY MANAGEMENT

11-1 Definitions

11-2 Calibration

11-3 Determination of MuzzleVelocity for Subsequent Lots-

REGISTRATIONS ANDAPPLICATION OFREGISTRATION CORRECTIONS

Characteristics

12-1 Types of Registrations12-2 Assurance Tables12-3 When to Conduct

Registrations

Precision Registrations

12-4 Definition and Objective

Page

10-42

10-42

10-42

11-111-2

11-6

12-1

12-112-2

12-3

12-4

12-412-5 Initiation 12-412-6 Impact Portion of the

Registration 12-412-7 Registering Piece

Displacement 12-612-8 Time Portion of the

Registration 12-612-9 Multilot Precision

Registrations 12-812-10 Abbreviated Registration

With the G/VLLD 12-812-11 Determination of a GFT

GFT Setting From a

Registration 12-812-12 Met + VE With a CheckRound 12-10

HB/MPI Registrations 12-1012-13 Objective 12-1012-14 Selecting an Orienting

Point__ 12-1112-15 Orienting the

Observers 12-12

FM 6-40

viii



12-16 Determining FiringData

12-17 Firing the HB/MPIRegistration

12-18 Determining the Mean BurstLocation12-19 Determining Chart Data

12-20 Determining Adjusted Data__

Radar Registrations

12-21 Employment

12-22 Advantages12-23 Conducting a Radar

Registration12-24 Selecting an Orienting

Point12-25 Radar Message to

Observer12-26 Determining Firing Data_12-27 Firing the HB/MPI

Registration12-28 Determining the Mean

Burst Location12-29 Determining Chart Data and

Registration Corrections

Registration Corrections

12-30 Description12-31 Computation of Total Range

Correction12-32 Computation of Total Fuze

Correction12-33 Computation of Total

Deflection Correction12-34 Registration Transfer

Limits

CHAPTER 13.

Section I.

SPECIAL CORRECTIONS ANDSPECIAL SITUATIONS

Basic Correction Data 13-1

13-113-213-313-413-5

Piece DisplacementEstimation/PacingHasty TraverseSurveyBallistic Computers

FM 6-40

Page

Section IV.

Section V.

12-13

12-14

12-1512-19.12-19

12-35

12-21

12-22

12-22

12-22

12-2412-24

12-26

12-28

12-27

12-27

12-27

12-27

12-28

12-28

12-29

13-113-213-213-213-2

ix



13-6 Description of the M1O/M 17Plotting Board

13-7 Preparing the M10/M17Plotting Board

Position Corrections

13-8 Types of PositionCorrections

13-9 Registration/SpecialCorrection Work Sheet

13-10 Registration Portion13-11 Hasty Correction Portion_ _13-12 Special Correction Portion_____13-13 Parallel Sheaf13-14 Converged Sheaf13-15 Special Sheaf13-16 FADAC13-17 Battery Computer System13-18 Hand-Held Calculator

Section II.

Section III.

Section IV.

Section V.

Section VI.

FM 6-40

Attack of Large Targets

13-19 Methods of Attack13-20 Target Division Method_13-21 Massed Fire Distribution

Template Method13-22 Sweep and Zone Fires

Final Protective Fire

13-23 Description13-24 Manual Computation of Data

With the GFT or TFT

Observers

13-25 Air Observer Considerations13-26 Observer Directions/

Spotting Lines13-27 Ranging Rounds

13-28 Time of Flight/Shot/Splash

13-29 Computer Procedures13-30 Untrained Observers

Zone-to-Zone Transformation

13-31 Description

13-32 Cutting and Joining Tw oGrid Sheets

Page

13-2

13-3

13-11

13-11

13-1213-1213-14.13-1513-16

13-1613-2413-3213-3213-32

13-33

13-3313-33

13-35

13-3513-38

13-38

13-39

13-39

13-39

13-4013-40

13-4113-41

13-41

13-42

13-42

13-44



Section VII.

CHAPTER 14.

Section I.

Section I1.

Section I1.

13-33 Graphic Method

13-34 Computer Procedures

High-Angle Fire13-35 Description13-36 High-Angle GFT

13-37 Duties of Personnel

13-38 HE High-Angle Missions

13-39 DPICM High-AngleRegistration

13-40 Computer Procedures

EMERGENCY PROCEDURES/OBSERVED FIRING CHARTS

Observed Firing Charts

14-1 Emergency FiringCharts

14-2 Construction of anEmergency ObservedFiring Chart

14-3 Battery ObservedFiring Charts

14-4 Determination of Direction forPolar Plotting

14-5 Determination of Range andAltitude-ImpactRegistration

14-6 Determination of Range andAltitude-Time Registration,Site Unknown

14-7 Determination of Site byFiring (XO's High Burst)

14-8 GFT Settings

14-9 Observed Firing Chart WithIncomplete Survey

14-10 Construction of Observed FiringChart-Position Area SurveyOnly

Useof

the M10/M17 PlottingBoard

14-11 Determination of Map Data_14-12 Conversion of Map Data

Into Fire Commands14-13 Determination of Data for

Subsequent Rounds

Map-Spot Surveyed FiringChart

FM 6-40

Page13-44

13-47

13-4713-47

13-4813-4913-50

13-5613-57

14-114-1

14-2

14-4

14-4

14-5

14-5

14-614-7

14-7

14-7

14-714-7

14-8

14-8

14-9

xi



14-14 Determination of SurveyedLocation and Azimuth of Lay.

14-15 Map-Spot Technique14-16 Construction of a Map-Spot

Surveyed Firing Chart(Manual)14-17 Transfer From Map-Spot to

Surveyed Firing Chart

APPENDIXES A. HASTY SPECIAL CORRECTIONTABLESA-1

B. INTERCHANGEABILITY OFAMMUNITIONB-1

C. FIRE DIRECTION CENTEREQUIPMENTC-1

D. EMPLOYMENT OF ARMOR ININDIRECT FIRED-1

E. INTERNATIONALSTANDARDIZATIONAGREEMENTSE-1

F. STANDARDIZEDPROCEDURESF-1

G. HOW TO TRAIN FIRE DIRECTIONCENTER PERSONNELG-1

H. TARGET ANALYSISANDMUNITIONS EFFECTSH-1

SAMPLE PROBLEM KNOWNDATA I-I

J. NEW DEPARTMENT OF THE ARMYFORMS J-1

K. GUNNERY TEAM PROCEDURESUSING THE GROUND/VEHICULARLASER LOCATORDESIGNATOR K-1

GLOSSARY GLOSSARY-1REFERENCES REFERENCES-1INDEX INDEX-1

xii

FM 6-40

Page

14-914-10

14-10

14-10



FM 6-40

Preface

FM 6-40 provides an explanation of equipment and munitions and their

associated fire direction procedures for the field artillery (FA) cannonsystems. This publication serves as the basis for operational procedures for

technical fire direction and as a guide for unit training. It has been

developed with the five basic rules of combat applied: move, shoot,

communicate, secure, and sustain.

The target audience of this publication includes trainers and supervisors

of cannon fire direction centers, battalion/brigade operations sections, and

others who need an understanding of technical cannon fire direction.

Certain chapters are the "how to" references for 13E soldier's manual tasks.

Users must be familiar with and use FM 6-20, FM 6-20-1, FM 6-30, FM 6-50,and FM 6-141-1/2.

It is envisioned that this will be the final edition of FM 6-40. Changes to

this edition will be published as new equipment, ammunition, or procedures

are developed. A training circular (TC 6-1-2) and a job aids have been

published for the battery computer system (BCS). The backup computer

system (BUCS) program will be fielded in 1985. When this program is

completed and a decision on the hardware is made, a BUCS job aids will be

published. A new FM containing BCS and BUCS fire direction procedureswill be published and fielded in FY 86.

Field artillery doctrine concerning firing unit survivability requires

technical procedures that allow the unit to occupy large areas of terrain in

the best possible way. Occupation of a position greater than 250 meters by

150 meters requires special corrections to firing data.

a. The battery computer system automatically applies special aiming

points and sheafs for all weapons in the unit.

b. The field artillery digital automatic computer (FADAC) or manual

fire direction procedures require the application of special corrections to

firing data. Two methods may be used.

(1) Mass fires of the platoons (plt) onto the target. This procedure

requires plotting the platoon location on the firing charts and computing

separate sets of firing data for each platoon (or using FADAC mass fire for

the separate platoon centers).

(2) Use special corrections to battery (btry) center data for eachplatoon. These corrections normally are done by using hasty correctionsfrom tables discussed in chapter 13 and included in appendix A. If time

permits, individual piece corrections may also be computed manually (chap

13).

c. When firing data are being computed manually, the unit commandershould consider positioning one weapon at the geographical battery center.

xiii



FM 6-40

This is not a requirement; however, manually computed fires will be moreaccurate if the adjusting piece is located at the point used as the battery (orplatoon) center. In all cases, common sense and the tactical situation dictatethe emplacement of weapons and the selection of technical firing datatechniques.

The order of technical, data computation is BCS, tactical fire directionsystem (TACFIRE) modification solution, BUCS, manual, and hand-heldcalculator (HHC). For further discussion, refer to chapter 4.

Included in this publication are guidelines for the interchangeabilty ofammunition (app B), a listing of fire direction center equipment (app C), anda discussion on employing armor in the role of indirect fire (app D).

Users of this publication are encouraged to submit recommended changesor comments to improve the publication. Comments should be keyed to aspecific page, paragraph, or line of text in which the change isrecommended. Reasons should be included for each comment to ensureunderstanding

and complete evaluation. Changes and comments should beprepared on DA Form 2028 (Recommended Changes to Publications andBlank Forms) and forwarded directly to:

CommandantUS Army Field Artillery SchoolATTN: ATSF-GAFort Sill, OK 73503

The provisions of this publication are the subject of standardizationagreement (STANAG)/quadripartite standardization agreement (QSTAG)

4119/220 and QSTAG 224. See appendix E.This publication contains standardized procedures relevant to field

artillery cannon gunnery. Those procedures are denoted in the text by anasterisk (*). See appendix F.

xiv

When used in this publication, he, him, his, and menrepresent both the masculine and feminine genders unlessotherwise stated.



FM 6-40

HOW TO USE THIS PUBLICATION

This publication is a reference and training document for technical

cannon fire direction. It may be used by all persons needing this

information. Information and tasks required by persons performing specificduties are addressed in various chapters. The entire publication defines andlists all technical fire direction tasks and provides information needed by

the gunnery team to successfully perform technical fire direction.

Below is a guide showing the chapters that will be of use to personnel in

specific jobs. These chapters should be used as primary references beforeother parts of this or other publications are consulted.

~imx.i:uu2

UK

- UR.OEAORULi m * ~~~jIUK

xv

ps 01 ia I I

FA-UNIT':.COMM.ANID-ERSI-FIR'E DIRECTION'OFFICER.COMPUTERS SHOULD READ ALL CHAPTER

FA BRIGADE/BATTALION"'S3sSHOULD'READ CHAPTERS 1 2 3 4"..

13, AND 14,

COMPUTER/BCS OPERATOR'S SHOULD READ CHAPTERS 1. 10. 11.9

RADIOTELEPHONE OPERATORS SHOULD READ CHAPTE

'0 .BSERVERS SHOULD READ CHAPTERSI., 2= BLJEA



FM 6-40

T he field artillery gunnery team con-sists of the observer, the fire direc-

tion center (FDC), and the firing battery,all linked by an adequate communica-tions system.

1-1. OBSERVERa. The observer/target acquisition assets

serve as the eyes of all indirect fire systems.An observer detects and locates suitableindirect fire targets (tgt) within his zone ofobservation. When a target is to be attacked,the observer, when necessary, transmits arequest for fire and adjusts the fires onto thetarget. An observer provides surveillancedata of his own fires and any other fires in hiszone of observation.

b. Maneuver personnel may function asobservers. When an individual detects andlocates a suitable target, he transmits arequest for fire, adjusts the fires onto thetarget when necessary, and providessurveillance data of his fires and any otherfires in his zone of observation.

c. Target acquisition devices alsofunction as observers and provide accurateand timely detection, identification, andlocation of ground targets to collectcombat/target information, to orient/cueintelligence sources, and to permit immediateattack on specific areas. Once combat begins,initial artillery targets will be located by theuse of the following field artillery targetacquisition assets:

(1) Moving-target-locating radarsections.

(2) Weapon-locating radar sections.

(3) Sound ranging platoons.(4) Remotely piloted vehicles (RPV).

Note. See FM 6-121 and FM 6-122 for adiscussion of these assets. I

1-2. FIRE DIRECTIONCENTER

The FDC is the control center for thegunnery team. The FDC personnel receivefire requests from the observer and processthat information by using tactical andtechnical fire direction procedures. They plotthe target on the firing chart or a map,determine firing data, and issue firecommands to the firing battery weaponsdesignated to fire the mission. The batteryFDC normally conducts technical firedirection by using the BCS or a backupmeans while the battalion (bn) FDC conductstactical fire direction with TACFIRE.Technical fire direction is the process ofconverting weapon and ammunitioncharacteristics (muzzle velocity, propellanttemperature, and projectile [proj] weight),weapon (wpn) and target location, andmeteorological (met) information into firingdata. The results of this process are charge,



FM 6-40

fuze (fz) setting, deflection (df), and quadrantelevation (QE). Tactical fire direction is theprocess of analyzing fire requests anddetermining appropriate fire method,ammunition expenditure, unit(s) to fire, andtime of attack.

1-3. FIRING BATTERYThe firing battery consists of the howitzer

sections and the ammunition section.Organization and employment con-

siderations are discussed in FM 6-50 and FM6-20-1.

1-4. COMMUNICATIONSLINKS

The gunnery team communications linksconsist of voice and digital communications.All members of the gunnery team mustaggressively ensure adequate com-munications are established and maintainedat all times.

1-2



FM 6-40

F ield artillery weapons normally areemplaced in defilade to conceal

them from the enemy. Usually, this

emplacement precludes direct fire onthe target. Consequently, indirect firemust be used to attack targets. Thegunnery problem is indirect fire. Thesolu t ion to th is problem r equ i r e sw e a p o n and a m m u n i t i o n se t t ingswhich, when applied to the piece andammunition, will cause the projectile toburst on the target or at a proper heightabove the target.

2-1. GUNNERYPROBLEM SOLUTION

a. The steps in solving the gunneryproblem are as follows:

(1) Know the location of the gun anddetermine the location of the target.

(2) Determine char t (map) data(direction, range [rg], and angle T).

(3) Compensate for nons tandard

conditions that would have an effect on firingdata.(4) Convert chart data to firing data

(charge [chg], fuze setting, deflection, andquadrant elevation).

(5) Apply the firing data to the gun andammunition.

b. The solution to the problem providesweapon and ammunition settings that causethe projectile to burst on the target or at apredetermined height above the target.

2-2. REQUIREMENTSFOR ACCURATEPREDICTED FIRE

In solving the gunnery problem,requirements for timely and accuratelydelivered cannon fire support must be met.When maintaining the demanding level ofcannon fires, adjustment cannot be made inevery situation. The goal, instead, is toachieve accurate predicted fires to producefirst-round fire-for-effect (FFE) missions.Such non ad ju s t ed f i r ing h a s fiverequirements that must be met to achieve thisgoal (fig 2-1). These requirements are targetlocation and size, bat tery location,

ammunition and weapon information, metinformation, and computational procedures.If these requirements cannot be metcompletely, degraded FFE missions mayresult and may have to be replaced with time-consuming adjust fire missions that wouldreduce the effectiveness of cannon firesupport.

a. Target Locat ion a n d Size. Toestablish the range from the gun to the target,the accurate and t imely detect ion,identification, and location of ground targets

and their size and disposition on the groundmust be determined so that accurate firingdata can be computed. To determine theappropriate time and type of attack, thetarget size (radius or other dimensions) andthe direction and speed of movement mustalso be considered. Target location isdetermined by the use of the assets mentionedin paragraph 1-1.

b. Battery Location. Accurate rangeand direction from the firing battery to the

2-1



FM 6-40

target also require the weapons to be locatedaccurately, and this location must be knownto the fire direction center. The position andazimuth determining system (PADS) canprovide accurate survey information on thebattery location. Survey techniques available

to the firing battery can also help indetermining the location of each weapon. TheBCS can identify the grid location of eachpiece from the aiming circle and can computethe geographical battery center grid. TheBCS uses each weapon location individuallyto compute individual firing data. The term"battery center" indicates the geographicalcenter of the weapons and does notnecessarily correspond to any weaponlocation. No longer is there a base piece. Foran adjust fire mission, the BCS automaticallydesignates a different weapon for each

mission based on an algorithm in themachine. The FDC, if required, may alsomanually designate an adjusting piece to thebattery computer system.

c. Ammunition and Weapon Informa-t ion. In the battery computer system,accurate firing data are based on the actualperformance of each weapon. The actual

performance is determined by the weapon'smuzzle velocities. The firing battery canmeasure actual muzzle velocity by using theM90 velocimeter (chap 11) and correct it tostandard for each weapon, type of propellant,and type of projectile. There is no longer arequirement to conduct a formal calibration,because calibration is conducted continu-ously by using the M90. Firing tables andtechnical gunnery procedures allow the unitto account for specific ammunit ioninformation (weight, fuze type, rocket motortemperature, or timer temperature); thus,accurate firing data are given.

d. Meteorological Informat ion. Theeffects of weather on the projectile in flightmust be considered. Use of currentmeteorological information (chap 10) in the

computers and in manual computationallows the firing data to compensate forcurrent weather conditions.

e. Computational Procedures. Thecomputation of firing data must be accurate.Procedures programed in the ballisticcomputers and the manual techniquesdesigned for firing data computation yieldaccurate firing data.

Figure 2-1 Five requirements for accurate predicted fire.

2-2



FM 6-40

B allistics deals with the motion ofprojectiles and the conditions that

affect that motion. An understanding ofballistics is important because it is uponthe fundamentals of ballistics that firedirection procedures are built. It is alsoimportant to unders tand the factorsaffecting round-to-round varia t ions ,particularly in muzzle velocity, so thatthey can be minimized and the goal ofaccurate predicted fires can be achieved.

Section IINTERIOR BALLISTICS

3-1. DESCRIPTION CENTERING SLOPE

Interior ballistics deals with the factors 0affecting the motion of the projectile within BREECH 9 MUZZLE

the tube. Interior ballistics determines thedeveloped muzzle velocity of a round when itleaves the tube. CONE

a. Propellant . Artillery propellant is alow-order explosive that burns at a rate less

than 1,300 feet per second.A low-order LAN

explosive burns rather than explodes. Itburns rapidly and releases gases as opposedto exploding and causing an instantaneousrelease of energy. The melting point for alow-order explosive is lower than thetemperature required to cause it to chemicallyreact. Therefore, it requires a primer for BORE -

ignition. CENTER GROOVE

b. Cannon Tube. Several parts of thecannon tube affect interior ballistics (fig 3-1). Figure 3-1. The cannon tube.

3-1



FM 6-40

(1) The rifled portion of the tubeimparts spin to the projectile to causestabili ty in flight. The groove is thedepression in the rifling. The land is theraised portion. These parts engrave therotating band.

(2) The caliber of a tube is the insidediameter of the tube as measured betweenopposing lands.

(3) Caliber length is the length of thetube in terms of its caliber. Caliber lengthequals tube length divided by diameter.Weapons can be classified by caliber.Technically, mortars have 10 to 20 caliberlengths, howitzers have 20 to 30 caliberlengths, and guns have more than 30 caliberlengths. All US artillery has a uniform right-hand twist in rifling except the M102 105-mm

howitzer, which has an increasing

right-hand twist . This exception wasrequired by the velocity and accuracyrequirements for the obsolete 105-mm charge8 propellant.

(4) The forcing cone is the rear portionof the main

bore formed by the tapered lands.It allows the rotating band to be engagedgradually by the rifling.

c. Projecti le. The projectile body hasseveral areas that affect ballistics (fig 3-2).Three of these areas affect interior ballistics.

(1) Bourrelet. The bourrelet is thearea of maximum diameter of the projectile,slightly less than the diameter of the bore. Itallows the projectile to ride snugly along thelands of the tube.

(2) Rotat ing band. The rotatingband is a band of soft metal (copper alloy)

EYEBOLT LIFTING PLUG- 0

-WEIGHT ZONE MARKING

O G I V E . - _ 1 f

KIND OF FILLER

TYPE AND MODEL OF SHELL

BOURRELET

BO DY - "

D54STAMPED IN THE METAL

UNDER THE PAINT:LOT NUMBER OF EMPTY SHELLYEAR OF MANUFACTURECALIBER AND DESIGNATION OF SHELL

GROMMET(PROTECTS ROTATINGBAND DURING SHIPMENT)

CALIBER AND TYPE OF WEAPON

.-. LOT NUMBER OF LOADED SHELL

FOR DEEP CAVITY SHELL CONTAININGSUPPLEMENTARY CHARGE

4 - DEPARTMENT OF DEFENSEIDENTIFICATION CODE

ROTATING BAND

OBTURATING BAND (USEDON CERTAIN PROJECTILES)

- BASE-BASE COVER

Figure 3-2. The projectile.

3-2





FM 6-40

d. Tube Wear. Continued firing of acannon wears away portions of the bore bythe actions of hot gases and chemicals andmovement of the projectile. These erosiveactions are more pronounced when highercharges are fired. The greater the tube wear,the more the muzzle velocity decreases.Normal wear can be minimized by carefulselection of the charge and by propercleaning of both the tube and theammunition.

e. N o n u n i f o r m Ramming . Hard,uniform ramming is required for all rounds.Weak, nonuniform ramming causes acombined effect of escaping gases and asmaller propellant chamber. These factorsproduce an increase in the dispersion pattern.

f. Rotating Bands. Rotating bandsallow uniform pressure buildup and provide aminimum dragging effect on the projectileonce motion has started. Dirt or burs on therotating bands cause improper seating. Thisincreases tube wear and contributes tovelocity dispersion. If excessively worn, thelands may not sufficiently engage therotating bands to impart the proper spin tothe projectile. Insufficient spin reducesprojectile stability in flight and can result indangerously erratic round performance.When erratic rounds occur or excessive tubewear is noted, ordnance teams should berequested to determine the serviceability ofeach tube.

g. P r o p e l l a n t a n d Pro jec t i l eTemperatures. Positive action must betaken to maintain uniform projectile andpropellant temperatures. Failure to take thisaction results in erratic firing. The effect of anextreme change in projectile or propellanttemperature can invalidate even the mostrecent registration corrections.

h. Moisture Content of Propellant.Changes in the moisture

content ofpropellant are caused by improper protectionfrom the elements. These changes will affectmuzzle velocity.

i. Pos i t ion of P r o p e l l a n t in th eC h a m b e r. In fixed and semif ixedammunition, the propellant has a relativelyfixed position with respect to the chamber. Inseparate-loading ammunition, however, theposition of the propellant depends on how thecannoneer inserts the charge. To ensure

proper ignition of the propellant, he mustinsert the charge so that the base of thepropellant bag is flush against the obturatorspindle when the breech is closed.

j. Weight of Projectile. A heavier-

than-standard projectile causes a decrease invelocity. A lighter-than-standard projectilecauses an increase in velocity.

k. Coppering. Coppering is the depositof a thin film of copper on the bore lands. Itoccurs in the tube when the velocity is highenough to develop sufficient friction toremove the outer surface of the rotating band.The amount of copper deposited varies withvelocity. Excessive coppering causes erraticvelocity performance by varying theresistance of the bore to projectile movement.Coppering may be reduced by firing

lowercharges and removed by cleaning the bore.

1. Prope l l an t Residue. Residue fromburned propellant and certain chemicalagents mixed with the expanding gases aredeposited on the bore surface. Proper care andcleaning will alleviate pitting and otherdamage to the tube.

m. Tube Condit ioning. The tempera-ture of the tube has a direct bearing on thedeveloped muzzle velocity. A cold tube offersa different resistance to projectile movement

and is less susceptible to coppering, even athigh velocities.

n. Tube Memory. Tube memory is thephenomenon that occurs when the tube firesat a muzzle velocity similar to that of the lastcharge fired, even if the charge is different.For example, if tht charge fired was 5 greenbag (GB) and the next charge to be fired is 3green bag, the tube will fire at a slightlyhigher muzzle velocity than normal forcharge 3, because it "remembers" firing thecharge 5.

3-3. MUZZLE VELOCITYMEASUREMENT

Various methods are used to determine thedeveloped muzzle velocity of a projectile. Useof the M90 velocimeter is the preferredmethod. It gives a real-time muzzle velocitythat can be used to better realize the artillerygoal of accurate predicted fires.

3-4



FM 6-40

Section IIEXTERIOR BALLISTICS

3-4. DESCRIPTIONExterior ballistics deals with the factors

that affect the motion of a projectile outsidethe tube.

3-5. TRAJECTORYELEMENTS

The trajectory is the path traced by thecenter of gravity of the projectile from the

origin to the level point. The elements of atrajectory are classified into three groups:intrinsic, initial, and terminal.

a. Intrinsic Elements. Elements thatare characteristic of a trajectory, bydefinition, are intrinsic elements.

(1) Origin-the location of the center ofgravity of the projectile when it leaves thetube. It also denotes the center of the muzzlewhen the piece has been laid.

(2) Ascending branch-that portionof the trajectory that is traced by the center ofgravity while the projectile is rising from theorigin.

(3) Descending branch-that portionof the trajectory that is traced by the center ofgravity while the projectile is falling.

(4) Summit-the highest point of thetrajectory.

(5) Maximum ordinate-the differ-ence in altitude (alt) between the origin and

the summit.(6) Level point-the point on the

descending branch that is the same altitudeas the origin.

(7) Base of trajectory-the straightline from the origin to the level point.

b. Initial Elements. Elements that arecharacteristic at the origin of the trajectoryare initial elements (fig 3-3).

Figure 3-3. Initial elements of the trajectory.

3-5

COMPLEMENTARY RANGE

LEGEND: 1. ANGLE OF SITE 4. ANGLE OF ELEVATION

2. COMPLEMENTARY 5. QUADRANT ELEVATIONANGLE OF SITE 6. JUMP

3. SITE 7. VERTICAL INTERVAL



FM 6-40

(1) Line of elevation-the-axis of thetube extended when the piece is laid.

(2) Line of departure-a line tangentto the trajectory at the instant the projectileleaves the tube.

(3) Jump-the displacement of the lineof departure from the line of elevation thatexists at the instant the projectile leaves thetube.

(4) Angle of site-the smaller angle inthe vertical plane from the base of thetrajectory to the straight line joining theorigin and the target. The angle of sitecompensates for the vertical interval.

(5) Complementary angle of site-an angle that is algebraically added to theangle of site to

compensate for thenonrigidity of the trajectory.

(6) Site-the algebraic sum of the angleof site plus the complementary angle of site(comp site). Site is computed to compensate insituations where the target is not at the samealtitude as the battery.

(7) Complementary range- thenumber of meters range correction equivalentto the number of mils complementary angleof site.

(8) Line of site-the straight line fromthe origin to a point, usually the target.

(9) Angle of elevation-the interiorangle at the origin in a vertical plane from theline of site to the line of elevation.

(10) Quadran t e l e va t i on - t h einterior angle at the origin in a vertical planefrom the base of the trajectory to the line ofelevation. It is the algebraic sum of site plusthe angle of elevation.

c. Terminal Elements. Elements thatare characteristic at the point of impact areterminal elements (fig 3-4).

(1) Point of impact- the point atwhich the projectile strikes the target area.

(2) Angle of fall-the vertical angle atthe level point between the line of fall and thebase of the trajectory.

(3) Line of fall-the line tangent to thetrajectory at the level point.

(4) Line of impact-a line tangent tothe trajectory at the point of impact.

(5) Angle of impact-the acute angleat the point of impact between the line ofimpact and a plane tangent to the surface atthe point of impact.

ORIGIN AdFIfoo JIIfl

LEVEL POINT

Figure 3-4. Terminal elements of the trajectory.

3-6



FM 6-40

3-6. ROUND-TO-ROUNDVARIATIONS

a. When several rounds are fired from apiece under conditions as nearly identical as

possible, the pointsof impact of the

projectiles will be scattered both in range andin direction. This scattering is calleddispersion. The area over the points of impactis called the dispersion zone.

b. Dispersion is the result of errors. Thereare three types of errors.

(1) Inherent errors-built-in errorsor inaccuracies in the weapon or ammunition(for example, play in the recoil system of ahowitzer). Inherent errors cannot becorrected for and are the primary cause of

dispersion.(2) Human errors-mistakes made by

any member of the gunnery team (forexample, inaccurate directions sent by thefo rward observer [FO], impropercomputation of data by the FDC, or improperlaying of the howitzer by the gunners).Human errors can be corrected by training.

(3) Constant errors-errors that areknown of and are constant throughout themission. Constant errors (for example, drift,VI, rotation of the earth) can be corrected byuse of the tabular firing table.

c. The center of the dispersion pattern iscalled the mean point of impact (MPI). TheMPI of a small number of rounds will differslightly from that of a larger number ofrounds, since a smaller number of roundscannot be expected to give a representativesample of the dispersion.

3-7. DISPERSIONRECTANGLES

a. If a rectangle is constructed around thedispersion zone (excluding any erraticrounds), it is called the 100-percent rectangle(fig 3-5). If this rectangle is divided into eightequal parts by lines drawn perpendicular tothe line of fire, the percentage of points ofimpact to be expected in each part is indicatedin figure 3-6. This is called a range dispersion

LINE OF FIRE •* • - • • • • . .

0 0

MEAN POINTOF IMPACT

Figure 3-5. The 100-percent rectangle.

3-7

0 0

0 0•0•

0 0 00 • 0 • • •

DA

v

a •



FM 6-40

rectangle. Likewise, if this rectangle isdivided similarly by lines parallel to the lineof fire, the percentages will be as indicated infigure 3-7. This is called a deflectiondispersion rectangle. Each division of thesedispersion rectangles is called 1 probableerror. Probable error is defined as the errorthat is exceeded as many times as not whenconsidering all rounds either over or short orleft or right of the mean point of impact.

b. If the range and deflection dispersionrectangles are superimposed, the result is theassemblage of small rectangles shown infigure 3-8. This result is called the dispersionrectangle. The percentage of points of impactin any particular small rectangle is theproduct of the percentages in two strips,range and deflection, whose intersections

form the small rectangle.

3-8. RANGE PROBABLEERROR

a. In figure 3-6, the line AB through thecenter of impact is perpendicular to the line of

fire. There are as many points of impact in thearea between AB and CD as there are beyondCD; that is, 25 percent of the points of impactare in the area AB-CD and 25 percent arebeyond CD. The depth of the area (AC) iscalled 1 range probable error (PER). Therange probable error for a given charge isdifferent at different ranges. Theapproximate value of the range probableerror is given in the firing tables. This valuecan be taken as an index of the.accuracy ofthe weapon. Firing table values for rangeprobable errors are representative ofcarefully selected ammunition. The actualprobable errors of an ammunition lot canvary from the table values. Probable error isthe value which, when added to or subtractedfrom the expected range, will produce aninterval along the line of fire that shouldcontain 50 percent of the rounds fired.Variations in muzzle velocity, angle ofdeparture, and total drag during flight affectthis value.

b. From studying figure 3-6, you willdetermine that 50 percent of the rounds willfall within 1 range probable error,approximately 82 percent will fall within 2

A CSHORT OVER

2% 7% 16% 25% 25% 16% 7% 2%

* 0

* 0 0

0 0 0 0*

• LINE OF FIRE* 0 0 •* 00.o 0 0

0 0 00

1/2- - - 1/2

B DMEAN POINT OF IMPACT

Figure 3-6. Range dispersion rectangle.

3-8



FM 6-40

probable errors, and 96 percent will fallwithin 3 probable errors of the mean point ofimpact. For practical purposes, it is assumedthat all rounds will fall within 4 probableerrors of the mean point-of impact. Actually, asmall percentage of the rounds (about 7 in

1,000) will fall farther than 4 probable errorsaway from the mean point of impact. Thisprobable distribution of rounds (includingthe fifth probable error) is given moreprecisely in the probability tables in thefiring tables.

3-9. DEFLECTIONPROBABLE ERROR

In the deflection dispersion rectangle (fig

3-7), the points of impact to the right and left

of the long axis of the rectangle follow

principles of distribution similar to those in

paragraph 3-7. For practical purposes, thedeflection probable error (PED) is taken as

one eighth of the width of the dispersionrectangle. This value is listed in the tabularfiring tables (TFT).

Figure 3-7. Deflection dispersion rectangle.

LEFT.02 .07 . 16 .25 .25 . 16 .07 .02

.02 .0004 .0014 .0032 .0050 .0050 .0032 .0014 .0004

1/2 .07 .0014 .0049 .0112 .0175 .0175 .0112 .0049 .0014

.16 .0032 .0112 .0256 .0400 .0400 .0256 .0112 .0032

c .25 .0050 .0175 .0400 .0625 .0625 .0400 .0175 .0050 LINE OF FIRE D

.25 .0050 .0175 .0400 .0625 .0625 .0400 .0175 .0050

.16 .0032 .0112 .0256 .0400 .0400 .0256 .0112 .0032

1/2 .07 .0014 .0049 .0112 .0175 .0175 .0112 .0049 .0014

.02 .0004 .0014 .0032 .0050 1.0050 .0032 .0014 .0004

RIGHT BMEAN POINT OF IMPACT

Figure 3-8. Dispersion rectangle.

3-9



Different units may have different 4-1. BCS/MANUAL FDCtypes and amounts of FDC equip-ment.

a. The battery FDC may be config-ured with one of the following threemixes of equipment:

(1) BCS/manual.(2) FADAC/manual.(3) Manual only.

b. The battalion will have TACFIREor will be a FADAC/manua l firedirection center.

c. Duties and responsibili t ies ofassigned personnel will vary dependingon the type and the amount of equipmentavailable in the fire direction center.

a. Duties of Personnel. The highestlevel of technical fire direction is found in aTACFIRE-controlled/BCS-equipped bat-tery FDC (fig 4-1). By tables of organizationand equipment (TOE), this FDC is authorizedeight people to fill four positions in two shiftsto facilitate 24-hour operations (TOE6-365J). Methods of training FDC personnelare in appendix G.

(1) One fire direction officer (LT)-is responsible for all FDC operations. The firedirection officer (FDO) actively supervises,decides how to attack the target (app H),ensures the required level of training isattained, and ensures a check of all knownand firing data.

Figure 4-1. BCS-equipped fire direction center.

4-2 FOLD

FM 6

LEGEND: DMD DIGITAL MESSAGE DEVICEFIST FIRE SUPPORT TEAMGFT GRAPHICAL FIRING TABLEG/VLLD GROUND/VEHICULARLASER LOCATOR DESIGNATOR

4-1



(2) One chief f i re direct ionspecialist (E6)-is the technical expert inthe fire direction center. He ensures smoothoperation of the FDC in 24-hour operations.He acts as a shift supervisor in the absence ofthe fire direction officer.

(3) Two computer operators (E5)-operate the battery computer unit (BCU) andsend fire commands to the guns.

(4) Two recorders (E4)-maintainrecords of firing data. As a minimum, therecorders should maintain the firing data of

the piece nearest the battery center and thedata required for backup with the hand-heldcalculator.

(5) Two chart operators (E3)-arethe horizontal control operator (HCO) andthe vertical control operator (VCO). Theymaintain a firing chart, follow each mission,and check the BCS grid coordinates withchart-and situation map coordinates. Thesedouble checks ensure that proper data arebeing used in the BCS solution. They also usethe BUCS/graphical firing table (GFT) fan to

provide an additional check of BCS firingdata for the adjusting weapon during theadjusting and fire-for-effect portions of themission.

b. Radio Communicat ions . Seefigure 4-2 for a diagram of the radiocommunications used in a direct support (DS)battalion equipped with TACFIRE and thebattery computer system.

c. System Degradat ion . With theintroduction of new technical equipment,

LEGEND: FSO FIRE SUPPORT OFFICERVFMED VARIABLE FORMAT MESSAGEENTRY DEVICEGDU GUN DISPLAY UNIT

Figure 4-2. Direct support battalion TACFIRE/BCS communications network.

FOLDIN 4-2

6-40

I4-2



FM 6-40

certain situations can cause technical firedirection system degradation. Acceptablegunnery solutions are available, but theynecessitate additional actions by certainpersonnel (table 4-1) and restructuring of

communicationsnets (fig 4-3).

4-2. FADAC/MANUAL FDC

a. Duties of Personnel. The FDO isresponsible for the operation of the FDC.Duties include producing accurate and timelyfiring data. The FDO analyzes the calls forfire and instructs the FDC on how to attack

the target. He is also responsible for checkingand entering known data into FADAC/BCS/BUCS/HHC and on the graphicalequipment. He and the chief fire directionspecialist (E6) actively supervise the rest ofthe personnel as they perform their duties.The chief fire direction specialist is theprimary technical advisor to the FDO, whotrains the section. The senior fire directionspecialist (E5) operates the FADAC andissues fire commands to the guns. The otherpersonnel serve as radiotelephone operator(RATELO), recorder, and chart operator, asdirected. The FADAC/manual FDC isshown in figure 4-4.

Figure 4-3. J-series battery fire direction nets used with the BCS.

4-3



FM 6-40

Table 4-1. Duties of personnel in the degraded FDC.

DEGRADATION 1 TACFIRE not available.

FDO/CHIEF Provides guidance to the computer operator for tactical fire control(BCS input). Normally, voice communications to the battalion FDCwill remain, and the battalion FDC will continue to control tacticalfire direction and issue the fire order. The battery FDO will guidethe BCU operator in filling in the FM:RFAF message format byusing the battalion fire order received by voice.

COMPUTER OPERATOR Enters appropriate FDO instructions and required data ensuringcommunications with appropriate digital subscribers aremaintained.

RECORDER Acts as radiotelephone operator (RATELO) if digitalcommunications are lost.

CHART OPERATOR Duties remain the same as in the nongraded mode.

DEGRADATION 2 BCS down/TACFIRE up.

FDO/CHIEF Issues orders to use BCS manual backup. Ensures the battalionverbal fire orders are received and followed.

COMPUTER OPERATOR Issues fire commands to the guns via vocal gun line. Operateshand-held calculator for a data check. Applies special correctionsto the TACFIRE solutions and records firing data or determinesplatoon's firing data based on individual platoon's chart data.

CHART OPERATOR Determines special corrections to apply to the TACFIREcenter-of-battery to center-of-target solution if the battery is notmassing platoons. Maintains situation map and prepares firingchart for backup.

DEGRADATION 3 BCS down/TACFIRE down.

FDO/CHIEF Issues orders to go to BCS manual backup. Provides guidance fortactical fire direction based on the battalion FDO's fire order.

COMPUTER OPERATOR Issues fire commands to the guns. Operates hand-held calculatorfor a data check. Applies

siteand

special corrections to the chartsolution and records data.

CHART OPERATOR Determines firing data by using the GFT fan (battery or platoons).Determines hasty special corrections, if applicable, and gives allthe information to the computer.

RECORDER Acts as RATELO. Determines site and assists computer as needed.

4-4



FM 6-40

Figure 4-4. FADAC/manual fire direction center.

b. Mission Processing. A call for fireis received in the FDC by the'RATELO. TheFDO analyzes the target' and issuesinstructions to the FDC on how to attack the

target.(1) The computer operator alerts the

firing battery of a mission and operatesFADAC, which masses the individualplatoons. FADAC is the primary source fordetermining firing data.

(2) The chart operator concurrentlydetermines firing data from the chart andfrom the GFT fan. These data provide thedata check on FADAC data. The chartoperator, maintains the situation map and,based on guidance from the FDO, announcesaverage site or determines and announces thesite for that.mission.

(3) The recorder records the mission onthe record of fire and prepares the hand-heldcalculator to follow the mission as backup.

(4) The chart operator double-checksthe FADAC firing data with his GFT-fan-determined firing data. If his center-of-battery to center-of-target solution checkswithin +3 mils deflection and quadrant

elevation and ±0.1 fuze setting increment, heannounces CHECK. Otherwise, heannounces HOLD. Before firing the data, theFDO ensures that data are checked. When

fire for effect is entered, platoons are massedon the target center. If individual platoonlocations are plotted on the firing chart, a setof firing data for each platoon to the targetmay be determined instead of having hastycorrections applied to battery center data.

c. System Degrada t ion . When theFADAC goes down, the FDC becomes amanual fire direction center. The recorderbecomes the second chart operator, and thecomputer acts as backup with the hand-heldcalculator. (The manual FDC'is Shown infigure 4-5.)

4-3. MANUAL FDC

a. Duties of Personnel. A manualbattery FDC is composed of the following:

(1) Fire direct ion off icer- i sresponsible for the training of all FD Cpersonnel, supervises the operation of theFDC, establishes SOP, determines method ofattacking targets, and ensures accuracy offiring data sent to the guns.

4-5



FM 6-40

Figure 4-5. Manual fire direction center.

(2) Chief fire direction specialist-serves as the FDO's technical expert andfunctions as the FDO in the FDO's absence.He ensures that all equipment is on hand andoperational, supervises computation of alldata, ensures that all appropriate records aremaintained, and assists the FDO asnecessary.

(3) Computer/senior fire directionspecial is t -combines data provided byother personnel. He determines andannounces firing data and fire commands.He also records mission-related data andother informat ion, as directed, anddetermines GFT settings.

(4) Horizontal control operator-constructs the primary firing chart,determines and announces chart data, andchecks firing data with the GFT fan.

(5) Ver t ica l cont ro l ope ra to r-constructs the secondary firing chart, checkschart data, determines and announces site,and provides corrections to firing data, byplatoon, from hasty correction tables, asrequired.

(6) RATELO-receives/records callfor fire and maintains communications.

b. Mission Processing.

(1) A call for fire is received in the FDCby the RATELO. The FDO analyzes the

situation and decides how the target will beattacked. The chart operators plot the target,announce chart data, and then determine VIand compute and announce site. Thecomputer determines and announces firingdata (the HCO checks or holds) andannounces fire commands to the guns. In firefor effect, the VCO enters hasty correction

tables and announces corrections tocenter-to-center fire-for-effect data for eachplatoon.

(2) The hand-held calculator (ifavailable) may be used as an alternatemethod of checking chart or firing data.

4-4. BATTALION FDC

a. Duties of Personnel. A TACFIRE-equipped battalion FDC is discussed in FM6-1. A battalion FADAC/manual FDC iscomposed of the following personnel:

(1) Fire direction officer-super-vises the FDC, analyzes targets, and issuesthe fire order.

(2) Chief computer-helps the FDOas required and trains the FDC personnel.

(3) Assistant chief computer-is thealternate for the chief computer.

4-6



FM 6-40

Figure 4-6. Employment of the fire direction nets (FADAC/manual).

Table 4-2. Duties of the battalion (tactical)and battery (technical) firedirection centers.

BATALION BATTERYFIRE DIRECTION FIRE DIRECTION

CENTER CENTER

Tactical fire direction Technical fire directionControl of mass fires Attack of other targets

Technical backup to as assignedbattery FDCs

Control of scheduledf res

Data update

(4) T h r e e c o m p u t e r s - p r o v i d eprimary communications between th ebattery and the battalion fire directioncenter. These people can provide technicalbackup to the battery if its FDC has anoverload or is neutralized.

(5) Horizontal control operator-has the same duties as the HCO in the batteryfire direction center and he operates theFADAC.

(6) Ver t ica l con t ro l o pe ra to r-determines and announces site and providescorrections to firing data, by platoon, from

hasty correction tables as required.(7) RATELO-has the same duties as

those of the RATELO in the battery firedirection center.

b. Rad io Communica t i ons . Figure4-6 shows the radio nets normally employedin a FADAC/manual DS battalion. Table 4-2summarizes duties of the two fire directioncenters.

4-5. 3x8 OPERATIONS

a. FM 6-50 describes the 3x8 concept inthe direct support field artillery battalion. Ifthe battalion is equipped with TACFIRE,each four-gun platoon's FDC has a batterycomputer unit. As in 3x6 operations,TACFIRE provides tactical fire direction,while the BCS provides technical firedirection and control.

4-7



FM 6-40

b. If no battalion FDC is available(autonomous operations), one of the tw oplatoon FDCs is the controlling FDC for theentire battery. All calls for fire are sent to thecontrolling fire direction center. The FDO ofthe controlling FDC reviews the message andperforms tactical fire direction. The fouroptions he may elect are discussed below.

(1) The controlling FDO may elect notto fire the mission, and the BCU operatordeletes the fire request. If the controlling FDOelects to fire the mission, he issues a fire order.The BCU operator makes entries in theFM;RFAF message format and processes themessage in accordance with the fire order.

(2) The target may be engaged by thecontrolling platoon only. In this case, the firerequest is processed as in 3x6 operations.

'(3) The target may be engaged by thesubordinate platoon only, and the mission ishanded off. The controlling platoon's BC Umust have the subordinate platoon entered inits BCS;INIT HOFFADD field. The BCUoperator enters an H in the FM;RFAFhandoff field and executes (EXEC) themessage. The FM;RFAF is transmitted to thesubordinate platoon's BCU, where it isprocessed as received. The observertransmits all subsequent messages to thecontrolling platoon. When executed, themessages are transmitted to the subordinate

platoon.(4) The target may be engaged by bothplatoons. The FM;RFAF and all subsequentmessages are transmitted to the subordinateplatoon from the controlling fire directioncenter. The messages are processed by bothplatoon fire direction centers. For adjust firemissions, one platoon must have DO NOTLOAD control until the fire-for-effect phase.

c. If TACFIRE becomes inoperable,tactical fire control will be provided by themutual support unit (MSU) if available.Otherwise, the battalion FDC

will performmanual tactical fire direction, or the batterywill operate autonomously.

4-6. FIRING DATA CHECKSThere are three separate checks on firing

data that must be done in the fire directioncenter. The FDO is responsible for seeing thatall firing data sent to the weapons aretechnically correct and do not violate any

known restrictive measures or commander'sguidance. The three checks are as follows:

a. K n o w n Dat a Check. In everybattery FDC, there are at least two separatefiring data sources (for example, the BCSwith firing charts or FADAC with firingcharts). The FDO directs that all known datainput 'into the computers be recalled andchecked for accuracy by someone other thanthe operator who entered the data. This checkensures that all operator-applied data(locations, met, muzzle velocities, or projectileinformation) are correct. The ballisticcomputers determine firing data based onthis information. The computationprocedures are correct, and, if known data arecorrect, the firing data determined by theballistic computers will be correct. Chartswill be checked for construction accuracy asdescribed in chapter 5.

b. Gr id L o c a t i o n Check . Gridlocations must be checked between the BC S(or FADAC) and the firing chart. The initialgrid for the FM;FC, FM;RFAF, or FM;SUBSis plotted on the chart, and a target grid isoriented for direction over that point.Subsequent corrections for the mission areplotted on the chart, and the grid location ofthe pin is checked against the grid location inthe CORD: field of the FM;SUBS messageafter the correction has been executed.Acceptable tolerance between

the two sourcesshould be ±30 meters in range. The hand-heldcalculator may also be used to accomplishchart verification. Accuracy depends on thetolerance of the computer to the chartverification done previously. If there areunresolved discrepancies, BCS data shouldbe used.

c. Weapon Firing Data Check. A-nother check may also be made as time andthe situation require. During the mission, theadjusting or centermost piece ballisticcomputer solution can be double-checked by

using graphical equipment. There will bedifferences in firing data solutions betweenthe computer and the manual method. In allcases, the ballistic computers are moreaccurate than the manual solution, becausethey account for more variables. Themagnitude of the difference will depend onthe chart-check tolerance, the validity of theGFT setting being used, and whether or notthe adjusting piece location is actuallyplotted on the firing chart or is displaced fromthe location.

4-8



FM 6-40

C hart data consist of range, deflec-tion from the firing unit to the tar-get, and angle T. These three elementsmay be determined by either electronic(TACFIRE, BCS, HHC, and FADAC) ormanual means. The manual methodrequires the construction and operationof a firing chart.

a. There are two types of firingcharts that may be constructed in theFDC: the surveyed firing chart and theobserved firing chart.

(1) The surveyed firing chart is achart on which the locations of allrequired points (battery or platoon [3x8]

positions, registration points[reg pt],

and observation posts [OP]) are plotted.These locations can be based on surveyor map inspection. All plotted points arein correct relation to one another andref lec t actual map coord ina tes .Addi t ional i n fo rmat ion such asloca t ions of t a rge ts , m a n e u v e r

checkpoints, no-fire areas, and safetydiagrams (training environment) mayalso be recorded.

(2) The observed firing chart is achart on which the relative locationsmust be established by the adjustment offire, hence, the name "observed firingchart." Details on construction and useof the observed firing chart are inchapter 14.

b. In the BCS- or FADAC-equippedfire direction center, a firing chart ism a i n t a i n e d as a backup and issupplemented by a 1:50,000-scale mapused to determine altitude. In th e

manual FDC, two firing charts aremainta ined. The vertical contro loperator maintains the backup chartand the 1:50,000-scale supplementarymap with the overlay(s), and th ehorizontal control operator maintainsthe primary firing chart.

Section I

TYPES OF SURVEYED FIRING CHARTS

5-1. DESCRIPTION

A firing chart is a graphic representation ofa portion of the earth's surface used fordetermination of distance and direction. Itmay be constructed by using a map, a

photomap, a grid sheet, or other material onwhich the relative locations of batteries,registration points, targets, and observerscan be plotted. Additional positions, firesupport coordinating measures, and otherdata needed for the safe and accurate conductof fire may also be recorded.

5-1





FM 6-40

c. Plot t ing Pins. Plotting pins areused to mark indexes and temporarypositions on the firing chart. On a1:25,000-scale chart, the thickness of theplotting pin equals 20 meters.

d. A l u m i n u m P l o t t i n g Scale . Thealuminum plotting scale (fig 5-3) is asquare-shaped scale used to plot or determine

grid coordinates. The scale is graduated inmeters and yards at scales of 1:25,000 and1:50,000. The meters scale is graduated every20 meters, and locations can be visuallyinterpolated to the nearest 1 meter. Care mustbe taken not to confuse the meters and yards

scales on this instrument. Paragraph5-5

details the procedure for plotting points withthe aluminum plotting scale.

TOP

0I SIDESLIDE THE PENCIL

Figure 5-1. The 6H pencil (wedge point).

ROTATE THE PENCIL

Figure 5-2. The 4H pencil (conical point).

I Z L S09 L 8 6 8S9 186000 S7 1 0001 000Z

C SaUVA0 000 0: 1S 0 00S 0001 00S8 000Z 2000

L 0 9

6 00S I

0001 2000 60 5z 0001 101E I oo 4

V 3OHS 2

9 1000 1

L 0000 1000

6 500 90000 8

• i ,r~ .., ... 0 6

2000 1500 1000 5001 :50 00

METERS 32000 1000 25 000 2

900if98765432 1 9 8 7 65 4 3 2 .Fi r.. .............. -.luminu .pl

Figure 5-3. Aluminum plotting scale.

5-3



FM 6-40

Figure 5-4. Range-

e. Range-Deflection Prot rac tor.The range-deflection protractor (fig 5-4) isused to measure angles in mils and distancesin meters. It is used to measure range anddeflection from a firing unit to a target anddirection and distance from an observer to atarget.

(1) The left edge of the instrument is thearm and is used to measure range or distance.It is graduated in 50-meter increments andlabeled every 500 meters on a scale of1:25,000. Ranges and distances are visuallyinterpolated to an accuracy of 10 meters.

(2) The 1,000-mil arc of the RDP isgraduated in 5-mil increments. The 50-milincrements are indicated by longergraduations and are permanently numbered.The arc is visually interpolated to anaccuracy of 1 mil.

(3) There are four different RDPmodels. They differ by maximum range of thearm (12,000, 15,000, 25,000, and 30,000meters).

-deflection protractor.

f. Target Grid.

(1) Description. The target grid is acircular paper or plastic device on which gridlines are printed (DA Form 4176 [TargetPlotting Grid Field Artillery Graduated inMils and Meters Scale 1:25,000]). These linesmatch the scale of the 1:25,000 firing chart,dividing a 1,000-meter grid square into100-meter squares. An azimuth scale isprinted around the outside edge of the targetgrid. It is graduated in 10-mil increments and

is numbered every 100 mils. An arrowextends across the center of the target gridand is used to indicate the observer-target(OT) line (or other line of known direction).The target grid should be labeled as shown infigure 5-5. Tape may be applied to the reverseside of the target grid to prevent the centerhole from becoming enlarged.

(2) Purpose and Use. The targetgrid is used for plotting the positions oftargets located by shift from a known point

5-4

'A,



FM 6-40

(para 5-10c), plott ing subsequent 5-50 POINT PLOTTINGcorrections, and determining angle T(section To plot points that have been located by

III). grid coordinates, proceed as follows:

a. Grid Lines 1,000 Meters Apart.

(1) Place a plotting pin in the upperright-hand corner of the grid square wherethe point is to be plotted (for example, grid60478 32859 [ ( , fig 5-6]). This pin willprevent the inadvertent plotting of the pointin the wrong grid square.

(2) Place the aluminum plotting scalealong the left edge of the grid square with the0 of the scale at the lower left-hand corner ofthe grid square ( ® , fig 5-6).

(3) Slide the scale to the right.Read

easting on the scale by using the north-southgrid line as an index ( © , fig 5-6).

(4) With the bottom edge of the scalealigned precisely on the east-west grid line,plot the northing on the vertical scale with aplotting pin. This is the plotted location

Figure 5-5. Labeling the target grid. ( ) , fig5-6).

Figure 5-6. Plotting with the aluminum plotting scale.

5-5



FM 6-40

b. Grid Lines Other Than 1,000Meters Apart.

(1) When grid squares are smaller thannormal, plot the easting or northing byinclining the aluminum plotting scale so thatthe 0 of the scale is on one grid line and the1000 is on the other (fig 5-7). The four-pointplotting technique (para (3) below) must beused.

(2) When grid squares are larger thannormal, incline the aluminum plotting scaleso that the 0 of the scale is on one grid line and2000 is on the other (fig 5-8). Multiply thedistance to be plotted by 2, and insert a pin atthat distance on the scale. For example, foran easting of 62681, place the pin at (62)1362on the scale.

(3) In both cases, only easting ornorthing can be plotted at one time.Therefore, the following four-point plottingtechnique must be used to plot a critical pointwhen grid lines are less than 1,000 metersapart.

(a) Locate the grid square in whichthe point is to be plotted.

(b) Using plotting pins and thealuminum plotting scale, plot the easting gridin the grid squares above and below the gridsquare in which the point is to be located.Remove the pins and connect the points witha fine line drawn with a 6H pencil through thecenter of the pinholes (fig 5-9).

Figure 5-7. Grid squares smaller than normal.

5-6



FM 6-40

Figure 5-8. Grid squares larger than normal.

Figure 5-9. Plotting the grid easting.

5-7



FM 6-40

(c) Plot the grid northing in the gridsquares to either side of the grid square inwhich the point is to be located (fig 5-10).Connect the pinholes with a line drawn witha 6H pencil.

(d) With a plotting pin, mark thepoint where the two lines meet (fig 5-11).Erase the fine lines and identify the locationwith a tick mark (para 5-6) (fig 5-12).

(e) The four-point plotting techniquemay also be used on a standard 1:25,000-scale firing chart. Easting is plotted along theeast-west grid lines bordering the grid squarewhere the point is located. Northing is plottedon the north-south grid lines bordering thegrid square. Only when accuracy is moreimportant than speed should this techniquebe employed.

Figure 5-10. Plotting the grid northing.

Figure 5-11. Marking the point where thetwo lines meet.

U I

Figure 5-12. Identifying the locationwith a tick mark.

5-6. TICK MARKSThe tick mark is the symbol used to mark

and identify the essential locations on afiring chart.

a. The tick mark is constructed in theform of a cross, with each arm beginning 40meters from the pinhole on the chart andextending 150 meters in length (1:25,000scale) (fig 5-13).

Figure 5-13. Drawing the tick mark.

b. The lines of the tick mark are drawnparallel to the grid lines unless the labelinginterferes with a previously labeled tick mark( ® , fig 5-14) or the plotted point falls on ornear (within 80 meters) a grid line ( © , fig5-14). In these cases, the tick mark is plottedon an 800-mil (450) angle to the grid line. Alltick marks are drawn with a 4H pencil except

5-8

1______________________________________________________________

Iare - i

Ii



FM 6-40

those for targets located by firing, which aredrawn in red, and for maneuver checkpoints,which are drawn in blue.

c. The identification of the point is placedin the upper right quadrant. The installation

or activity is designated in the followingmanner:

(1) Battery. The letter designation isshown in the appropriate color ( (U , fig5-14) (that is, A-red, B-black, C-blue,

•D-orange). If more than four batteries areshown, the color coding starts over againwith red. If the pieces of the battery are widelydispersed, it may be necessary to plot piece orplatoon locations (for example, platoons in3x8 operat ions) . Platoon or piecedesignations should be labeled by using thebattery's color code.

(2) Radar. The military symbol isshown in green ( ( , fig 5-14).

(3) Observation post. The militarysymbol for an observer and the call signnumber which will be used by the observer toidentify himself are shown in black ( S®Ifig 5-14). If the observation post is assigned anumber, that number is shown in black in

01 cs.1977

400

place of the symbol and call sign number (forexample, 01).

(4) Registration point. The numberassigned to the registration point is shown inblack (for example, REG PT 2 [ (" , fig5-14]).

(5) Target. The assigned targetnumber is shown in black (for example,CB2131 [ © , fig 5-14]).

(6) Checkpoint. The checkpoint tickmark is shown in blue, while its number isshown in black and circled (for example, O[ , fig 5-14]).

d. The altitude (alt), in meters, of theplotted point is placed in the lower leftquadrant in black ( B through © , fig5-14).

e. If the plotted point has been fired on,the fuze used in fire for effect may be placed inthe lower right quadrant ( I() , fig 5-14).

f. If the plotted point has been fired onwith high-angle (HA) fire, the letters HA maybe placed in the upper left quadrant. Thecharge that was used in the mission can alsobe indicated (clD , fig 5-14).

C%~ V IB424 1

(SYMBOL INGREEN)

5001

Q(LABELING OF TICKMARKS SHOULDBE KEPT WITHINQUADRANTS AS ICSMUCH AS 12131

POSSIBLE.) 4151

0A068

3001

(TICK MARKIN BLUE)

I0•. 37 6

I REGPT 2

4301

0CHG 51 CS

HA 2131

(ALT) I VT

I (FZ IN FFE)

Note: Identification and altitude of the tick mark must always be given.

Figure 5-14. Tick marks.

5-9



FM 6-40

Figure 5-15. Numbering on the r

5-7. CONSTRUCTION OFAZIMUTH INDEXES

a. Azimuth indexes are constructed forpoints located on the firing chart from whichthe polar plot method (para 5-10) of targetlocation may be expected (for example,observation posts and radar sites). The RDPmust be prepared by numbering the 100-milgraduations in black as shown in figure 5-15.

b. Azimuth (az) is always read as fourdigits. The first digit (thousands of mils) is

read from an index that is drawn on the firingchart. The last three digits are read from thearc of the range-deflection protractor.

c. Azimuth indexes are constructed on thefiring chart at 1,000-mil intervals throughoutthe target area except the 6000 and the 0indexes, which are 400 mils apart (fig 5-16).

(1) Place the vertex of the RDP againstthe pin in the observation post or radarlocation, and align the arm parallel to aconvenient grid line. If you are using anorth-south grid line, plot the easting of the

observer with a plotting pin. If you are usingan east-west grid line, plot the northing of theobserver in a similar manner. When the RDPis aligned with the vertex at the observer andthe arm against the pin, a reference line isestablished at an azimuth of 0 (north), 1600(east), 3200 (south), or 4800 (west). It is notdrawn.

(2) In (1) above, the RDP was orientedin a cardinal direction. To establish the

range-deflection protractor.

azimuth index, place a pin opposite thenumber on the arc corresponding to the lastthree digits of the azimuth in which the armof the RDP is oriented. The location of the pinrepresents an index. Its value is the value ofthe first digit of the azimuth in which the armof the RDP is oriented. If the arm is orientedtoward north, two azimuth indexes will beconstructed, since north corresponds to 6400and 0 mils (fig 5-16). These will be the 6000and 0 indexes. Table 5-1 summarizesindexing procedures for all orientations of therange-deflection protractor.

Figure 5-16. Plotting the 6,400-mil and0-mil temporary azimuthindexes.

5-10



FM 6-40

Table 5-1. Indexing procedures.

If RDP is oriented NORTH (6,400 mils or 0 mils),

(1) Place pin opposite 400 on ARC; INDEX is

6000.

(2) Place pin opposite 0 on ARC; INDEX is 0.

If RDP is oriented EAST (1,600 mils),

place pin opposite 600 on ARC; INDEX is 1000.

If RDP is oriented SOUTH (3,200 mils),


If RDP is oriented WEST (4,800 mils),


(3) To replace the plotting pin with aconstructed index, move the RDP so the left

edge of the arm is against the pin ( ® , fig

5-17). Remove the pin and, with a 6H pencil,

draw the azimuth index through the center of

the pinhole ( © , fig 5-17). The index is afine line extending 1 inch on each side of thepinhole. For example, in @ , figure 5-17,this line can be constructed by drawing a line

from range 8250 to range 9520 along the armof the RDP. Beginning one-eighth inchbeyond the pinhole, label the index with itsidentification and azimuth value (for

example, OlAZO [ , fig 5-17]). Letteringis green for the radar symbol and its azimuthlabels and black for observation posts andtheir azimuth labels.

Figure 5-17. Preparing an index.

5-11





FM 6-40

Figure 5-20. The range-deflection protractor prepared for measurement of deflection.

Figure 5-21. Range-deflection protractor oriented to the east.

5-13

DEFLECTIONDEFLECTION IS LABELED

WITHRED PENCIL

AZIMUTH IS LABELEDWITHBLACK PENCIL

Figure 5-22. Range-deflection protractor oriented on azimuth of lay.





- - -- 4P

1 1 I l l i ll-2-70i

Figure 5-25. Construction of supplementary deflection indexes.

Figure 5-26. The 6,400-mil firing chart.

5-9. 6,400-MIL CHARTS

When firing in a 6,400-mil sector isrequired, the firing units are plotted in thecenter of the firing chart. The indexes areconstructed and numbered as shown in figure5-26. Locally fabricated larger charts may benecessary to achieve the maximum rangethroughout the 6,400 mils.

5-15

FM 6-40



FM 6-40

Figure 5-27. Polar plot the target location.

5-10. METHODS USED IN

PLOTTING TARGETSa. Grid Coordinate. To plot points

located by the grid coordinate method, followthe procedures outlined in paragraph 5-5.

b. Polar Plot. To plot points located bythe polar method, proceed as follows:

(1) Place the vertex of the RDP againstthe pin at the OP, with the arc opposite theproper azimuth index.

(2) Align the RDP in the directionreported by the observer opposite the azimuthindex. In figure 5-27, the observer (01)reported a direction of 6200.

(3) Place a pin along the left edge of thearm of the RDP at the reported distance. Thisis the location of the target. In figure 5-27, theobserver reported a distance of 8,700 meters.

c. Shift From a Known Point. A shiftfrom a known point target is located relativeto a known point by using OT direction, alateral shift, a range shift, and a vertical

shift. The following method is used inplotting a target location:

(1) Place the center of the target gridover the location of the known point on thefiring chart and fix it in position with a pin.To orient the target grid, move the arrowparallel to a north-south grid line, with thearrow pointing north. Place a pin opposite 0on the scale. Then, rotate the target grid untilthe OT direction is opposite the pin. Thetarget grid is now oriented. In figure 5-28, thetarget grid is oriented in the directionreported by the observer, 1,100 mils. If it isanticipated that a location may be used as the

known point for future shift from a knownpoint target location (for example, aregistration point or a point recorded as atarget), a north azimuth index should beconstructed by use of the range-deflectionprotractor. Position and orient the target gridtoward north as before. Instead of placing apin opposite the 0, construct an indexopposite 0. The index extends 1 inch aboveand 1 inch below the target grid (approximaterange 2050 to 3300 on the RDP). Mark theindex N as shown in figure 5-29.

5-16



FM 6-40

Figure 5-28. Locating the target by shiftfrom a known point.

(2) Plot the shift given by the observer(left or right, add or drop) on the target grid.(Be sure to note the labeling of the targetgrid.) The pin will be in the target location.

EXAMPLE:

Observer reported (fig 5-28):SHIFT REGISTRATION POINT 1,DIRECTION 1100, RIGHT 150,DROP 400, OVER.

(3) If the initial shift plots the point offthe target grid, reposition the target grid sothat both points fall on the target grid. Orientthe target grid in the OT direction and plotthe shift (fig 5-30).

(4) Recenter the target grid over thetarget location and orient it to the reportedOT direction. This will permit the plotting ofsubsequent corrections and/or refinement.Once oriented, the target grid should be

secured at all times by at least two pins toavoid unintentional movement.

EXAMPLE:

Observer reports:

SHIFT REGISTRATION POINT 1,DIRECTION 1100, LEFT 500,DROP 2500, OVER.

Figure 5-29. Construction of a north index.

Figure 5-30. Locating the target when the initialshift plots off the target grid.

5-17



Section IIICHART DATA

Figure 5-31. Angle T.

5-11. CHART RANGE AND

CHART DEFLECTIONChart range and deflection are measured

as follows:

a. Place the vertex of the RDP against thepin in the battery position, and place the leftedge of the arm against the pin in the targetlocation.

b. Read the range, in meters, opposite thepin in the target location. Measure andannounce the range to the nearest 10 meters.

c. Read the chart deflection on the arcopposite the appropriate deflection index. Toobtain the deflection, combine the 1,000-mildesignation of the index with the reading onthe arc. Announce the deflection to thenearest 1 mil.

GUN-TARGET LINE

V ANGLET

0 1\

I,

FM 6-40 0

5-12. ANGLE TAngle T (fig 5-31) is the smaller interior

angle formed at the target by the intersection '

of the GT and OT lines. It will therefore neverbe larger than 3,200 mils, After the initialchart range and deflection are announced,the target grid is oriented over the targetlocation along the observer's direction. AngleT is then determined to an accuracy of 10 milsand announced by the chart operator. It ismeasured in the following manner:

a. With the target grid centered on thetarget pin and oriented along the observerdirection, place the vertex of the RDP at thefiring unit location and place the left edge ofthe arm against the target pin. Either the 0(head of the arrow) or 3200 (tail of the arrow)will be visible on the target grid to the left ofthe arm. Measure angle T eitherhead-to-head or tail-to-tail. That is, if the 0or head of the arrow is visible, determine thenumber of mils between the head of the arrowand the intersection of the arm of the RDP,with the target grid azimuth scale fartherfrom the vertex (fig 5-32). If the 3200 or tail ofthe arrow is visible, determine the number ofigure 5-32. Determine angle T (head to head).

5-18



FM 6-40

mils between the tail of the arrow and theintersection of the arm of the RDP, with thetarget grid azimuth scale closer to the vertex(fig 5-33).

b. When the pin is not centered on thetarget grid and the FDO directs you tomeasure angle T, move the target grid so thatthe pin is centered and reorient the OTdirection. Read angle T as described above.

direction, and thus causes angle T to becomeexcessive (greater than 500 mils).

b. If the observer is not stationary, heshould report a new OT direction if it changesmore than 100 mils. To plot the new direction

(and subsequent correction), center the targetgrid over the last pin location beforereorienting for direction.

Figure 5-33 Determine angle T(tail to-tail).

5-13. SUBSEQUENTCORRECTIONS

a. After the chart operator ha sdetermined chart range and deflection, hepositions and orients the target grid asdescribed in paragraph 5-11a. He thendetermines angle T. Subsequent observercorrections are plotted in the same manner asthe shift from a known point. Corrections arevisually interpolated to an accuracy of 10meters on the target grid. After the observer'scorrection is plotted, a new chart range anddeflection are determined. Angle T is notdetermined for subsequent corrections unlessthe observer requests it or changes his

5-14. MANUAL-TO-COMPUTER OR

CHART-TO-CHARTCHECKS

a. One chart will differ slightly from anyother because of small differences inconstruction caused by human limitations inreading the graphical equipment. Because ofthese differences, the following tolerancesbetween charts are permissible:

Range/distance: ±30 meters

Azimuth/deflection: ±3 mils

b. To check the accuracy of two or morecharts, plot the same grid intersection on allof the charts. Determine range and deflectionto that point from the same firing unitlocation on all charts. All firing unit locationsmust be checked for accuracy. If all rangesagree within 30 meters and all deflections forthe firing unit location agree within 3 mils,the checks are accurate for that firing unitlocation. If not, all charts must be checked forerrors.

c. To ensure accuracy, sufficient pointsshould be checked in the firing unit s zone ofoperations. For example, an error in plottingthe unit location on one chart couldcompensate for an error in construction of thedeflection index on the other chart. Checking

at least two points will reveal the error. Thisshould be done as a matter of unit standingoperating procedure.

d. To perform chart verification withBCS, use center of battery (the average of allpiece locations as displayed in the CORDfield of the AFU;UPDATE) and store as animaginary gun in BCS;PIECES. Center ofbattery corresponds to the battery location onthe chart. Individual weapon locations arenot plotted on the chart.

5-19



FM 6-40

EXAMPLE:

Enter center of battery coordinates and altitude as gun 12 in BCS;PIECES ormatin an ON (Y) status.FM;RFAF Enter grid intersection coordinates

and altitude of target.CORD: 68000/38000/361PTF (adjusting piece to fire): 12

EXECUTE Gun orders displayed (DO NOT XMIT)

FM;SUBS Enter target numberReplot (rep)Altitude

EXECUTE Displayed will be:

Replot rangeReplot azimuth

Use the GTRG and GTAZ to verify chartconstruction. When finished, change thestatus of the imaginary gun 12 to OFF (N) inBCS;PIECES. Accuracy tolerances are ±30meters range/distance and ±3 milsdeflection/direction.

e. To perform chart verification with thehand-held calculator, use the following

TG T: ABO021REP: XALT: 361

GTRG:GTAZ:

procedure: After battery setup in the HHC,enter the grid to the chart check location as atarget. Use the battery altitude as the targetaltitude. Determine deflection/direction andrange/distance from the HHC, and comparethese data to the chart data to the samelocation. Accuracy tolerances are ±30 metersrange/distance and ±3 mils deflection/direction.

5-20



FM 6-40

T here are three critical information-al messages in the processing of afire mission. The messages are the fire

order, the fire commands, and themessage to observer. In the fire order,the FDO tells the FDC how he has

decided to attack the target. The firecommands give all required informationto the guns to begin, continue, and cease

firing. The message to observer informsthe observer of the FDO's decision onhow to attack the target.

Section IFIRE ORDER

6-1. DEFINITIONWhen a request for fire is received at the

FDC, the FDO must determine how the targetwill be attacked if the unit is operating in anautonomous mode. When operating withTACFIRE, the battalion FDO checks the ploton the digital plotter map and inspects theTACFIRE solution. If he concurs with theTACFIRE solution, he directs it to betransmitted to the appropriate fire units. If hedisagrees with the TACFIRE solution, hemakes modifications and then transmits themodified message to the units. The TACFIREmessage is the fire order. In the autonomousmode or when the unit is equipped with theFADAC/manual system, the battery FDOmust inspect the target plot on the situationmap and conduct a brief analysis todetermine how the target will be attacked.The result of his analysis is announced in thefire order. A fire order is the fire directionofficer's decision on how the target will beattacked.

6-2. CONSIDERATIONS INATTACKING A TARGET

The FDO must consider several factors indetermining how, if at all, to attack thetarget. At the battalion FDC, the TACFIREwill analyze the target based on th ecommander's criteria and then present afiring solution to the FDO. The TACFIREtechnical firing solution will be for batterycenter to target center only. At the batteryFDC working in an autonomous mode or in abattalion FDC without TACFIRE, the FDOmust initially consider the following factors:

a. Locat ion of Target . Check thelocation relative to friendly forces, firecoordination measures, zones of fire, andtransfer limits. Range will affect the choice offire unit(s) and the charge. Terrain mayinfluence ammunition selection or the type oftrajectory. High intermediate crests mayrequire selection of a lower charge or use ofhigh-angle fire.

6-1



FM 6-40

b. Nature of Target. The size and typeof target will affect the type and number ofrounds to fire, any corrections for sheaf, andwhether surprise is possible.

c. Ammunition Available. Considerthe ammunition available and the controlledsupply rate (CSR).

d. Fire Units Available. Consider thenumber of fire units available at the time offiring.

e. Commander's Guidance/StandingOpera t ing Procedures . Operationorders, restrictions on ammunition, andSOPs may govern units and ammunitionselected, target attack priority, method ofattack, tactical mission, and desired

percentage of casualties.

f. Request for Fire. Consider theobserver's request, since he is observing thetarget and talking directly to the maneuvercommander.

g. Munitions Effects. Consider theeffects of munitions combinations as a guideto selecting the best munition to use in anattack.

h. Tactical Situation. Consider the

counterfire threat.

6-3. FIRE ORDER ELEMENTSIn autonomous operations, the battery

FDO must issue a fire order. This fire orderwill address any information needed toconduct the mission. If not covered by unitSOP, the following elements will beaddressed (table 6-1):

a. Unit to Fire, Unit(s) to Follow theMission, and Unit to Fire for Effect.Normally, BATTERY is announced as theunit to fire. If the fire order originates in theFADAC/manual battalion FDC and theFDO decides to fire the entire battalion, theelement is announced as BATTALION. Todesignate less than the entire battalion tofire, ALFA AND CHARLIE, for example,may be announced. Unit call signs should beused when units to fire are being discussedoutside the fire direction center.

b. Adjusting Element/Method of Fireof Adjusting Element (if Applicable).Normally, this will be the BCS-selected piecefiring one round. In manual operation, thecomputer will select the adjusting piece.

c. Basis for Correct ions. Thiselement specifies how data will bedetermined. Normally, BCU is specified.Those units not equipped with it maydesignate FADAC, the graphical firing table,the hand-held calculator, the graphicalfiring table fan, or the fastest method.

d. Distribution. This is the pattern ofbursts in the target area. The BCS willcompute individual aiming points for eachweapon on the basis of target description andlayout in the battery area. If the FDO desiresa different sheaf, he will announce it here. Ina manual/FADAC fire direction center, thedistribution will be accomplished accordingto BCU manual backup procedures or bymassing platoons with platoon center totarget center solutions.

e. Projectile. This is the projectile to befired in fire for effect.

f. Ammunition Lot and Charge. Theseare the ammunition lots and charges used inadjustment and fire for effect.

g. Fuze. This is the fuze to be used infire for effect.

h. Number of Rounds. This is thenumber of rounds to be fired in fire for effectby each howitzer.

i. Range Spread, Lateral Spread,Sweep and Zone, and High Angle. Theseare methods of attack used in specialsituations.

j. Time of Opening Fire. This is thetime when the guns may commence firing.They may fire when ready, at my command(AMC), or time on target.

k. Target Number. Each mission willbe assigned a target number, normally byTACFIRE, by BCS, or by the FDO if manualoperations are being conducted.

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FM 6-40

Table 6-1. BCS defaults as fire order elements.

ELEMENTS ADJUST FIRE, FIRE FOR EFFECTTHEN FIRE FOR EFFECT (NO ADJUSTMENT)

UNITTO FIRE BATTERY BATTERY

ADJUSTING ELEMENT/ BCU SELECTS/(Q FIRE FOR EFFECTMETHOD OF FIRE OFADJUSTING ELEMENT

BASIS FOR CORRECTIONS BCU BCU

DISTRIBUTION BCU SHEAF/DEFAULT BCU SHEAF/DEFAULTCIRCULAR 100-METER CIRCULAR 100-METERTARGET RADIUS TARGET RADIUS

PROJECTILE HE DPICM

AMMUNITIONLOT BCU SELECTS LOT AND BCU SELECTS LOT AN DAND CHARGE CHARGE CHARGE

FUZE POINT DETONATING TIME

NUMBER OF ROUNDS 1 , SHELL DPICM, BCUSELECTS LOT ANDCHARGE, FUZE TIME

RANGE SPREAD,LATERAL SPREAD,ZONE OR SWEEP

HIGH ANGLETIME OF OPENING FIRE WHEN READY WHEN READY

TARGET NUMBER NEXT AVAILABLE NUMBER NEXT AVAILABLE NUMBER

6-4. ISSUING THE FIREORDER

a. TACFIRE. In TACFIRE opera-tions, the battery FDO will execute thebattalion-directed fire mission that isdisplayed on the BCS or announced by voice.The FDO should note the location and natureof the target on the situation map to ensurethat the mission will not endanger friendlymaneuver operations and to serve as one ofthe firing data double checks.

b. Battery Computer System. Whenoperating with BCS in an autonomous mode,the battery FDO must compare the FM;RFAFdisplayed on the BCS with the known BCSdefaults. The target must be plotted on the

situation map as a double check. The FDOwill address any elements not covered bySOP that will change the BCS defaults. Forexample, the BCS will default to DPICM inthe fire-for-effect phase of the mission. TheFDO may not wish to expend DPICM andinstead might announce high explosive (HE)as the fire-for-effect ammunition.

c. FADAC/Manual. In the FADAC/manual FDC, the FDO has the followingadditional considerations in issuing fireorders:

(1) Level of training of FDC personnelwill affect the FDO's ability to establish SOP.

(2) Sequence of the fire order elementsmay facilitate timely processing of themission.

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FM 6-40

d. The FDO must ensure that the fireorder is clear and concise. The key to the fireorder is that it is understood by all personnelin the fire direction center.

(3) Normally, the FFE phase of anadjust fire mission is controlled byannouncing WHEN READY. It can be anAMC mission. Normally, time-on-targetmissions are not used, because the element ofsurprise is lost through adjustment.

6-5. BATTALION FIREORDERS

a. Battalion Fire Order Format. Innormal TACFIRE operations, the battalionfire order is transmitted to the fire unitsthrough TACFIRE message formats. Thebattalion FDO can agree with the TACFIREsolution or make appropriate changes. Theapproved message is sent to the fire units. Innon-TACFIRE operations, the battalion

sends voice fire orders. If a voice battalion fireorder is required, the fire order elementspreviously discussed will be announced withthe following modifications:

(1) A warning order is issued to indicatethe type of mission (adjust fire [AF], FFE).

(2) In the unit to fire, the adjustingbattery and batteries to fire in effect will begiven. In adjust fire missions, the adjustingbattery will follow the unit to fire (forexample, BATTALION, A).

(3) The target location and altitude areannounced.

b. Contro l of Bat ta l ion MassMissions.

(1) Fire-for-effect mass missions onstationary targets can best be controlled byusing time-on-target (TOT) techniques. Thetime on target may be announced as a specifictime (for example, TIME ON TARGET0915) or as a specific amount of time before itis to occur (for example, TIME ON TARGET5 MINUTES FROM...NOW). The preferredmethod of use by BCS/TACFIRE is thespecific time method.

(2) Fire-for-effect mass missions onmoving targets or targets of a fleeting natureare best controlled by using AT MYCOMMAND or WHEN READY (WR). Timeconsumed in coordinating a TOT may resultin rounds missing the target. Missionsoriginated by use of the G/VLLD can becoordinated by using the target predictionmethod.

6-6. BATTERY-LEVEL FIREORDERS

a. The driving force behind the fire ordershould be the fire order SOP established bythe fire direction officer. An example of a fireorder SOP is shown in table 6-2. This is theSOP used throughout the following

discussion.b. As discussed in paragraph 6-3, all

elements of the fire order must be addressedeither verbally or by the SOP.

(1) Unit to fire. Unless verballychanged, the unit to fire for effect will be thebattery.

(2) Adjusting element/method offire of adjusting element. The BCS willconduct an automatic selection routine todetermine the adjusting piece for each

mission. In any FDC that is a degradation ofthe TACFIRE/BCS fire direction center (noBCS or BCS down), the FDO may elect to usea similar process manually. For example, gunnumber 1 will adjust in mission 1 and gunnumber 2 will adjust in mission 2. Theadjusting piece will normally fire one round,shell HE, fuze quick (Q) in adjustment.

(3) Basis for corrections. Normal-ly, data are computed by use of the fastest.method available in the fire direction center.

(4) Distr ibution. The FDO an-

nounces the sheaf to be used based on the callfor fire (CFF) and target description. If theFDO agrees with the sheaf requested by theobserver, no announcement by the FDO isnecessary.

(5) Projectile. If the FDO decides touse the projectile that the observer requests,he does not have to verbally address thiselement. If the FDO decides to useIa projectileother than the one requested, he mustannounce this in his fire order.

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FM 6-40

(6) Ammunition lot and charge.The computer selects the projectile lot on thebasis of the projectile specified by the FDO'sfire order. The propellant lot and charge aredetermined based on the chart range andother tactical considerations.

(7) Fuze. If the FDO decides to use afuze other than that requested by theobserver, he must announce it in his fireorder.

(8) Number of rounds. The FDOannounces the number of rounds to be used inthe fire-for-effect phase.

(9) Range spread, lateral spread,zone and sweep fire, high angle. Theseelements will be addressed if applicable.

(10) Time of opening fire. If otherthan when ready, the time of opening firemust be addressed by the FDO.

(11) Targe t number. The nextavailable target number of the target block

will be used unless a number has previouslybeen assigned to the target.

Note. The EDO will use the sameprocedure as the observer in specifying theshell/fuze combination to be used for the

mission. For example, when the FDOannounces VT IN EFFECT, shell HE, fuzeVT will be used.

Table 6-2. Example of fire order standing operating procedures.

6-5

ELEMENT CURRENT STANDARD

UNIT TO FIRE BATTERY

ADJUSTING ELEMENT/METHODOFFIRE OFADJUSTING ELEMENT NEXTPIECE/Q

BASIS FOR CORRECTIONS FASTEST METHOD

DISTRIBUTION OBSERVER OR FDO WILLSELECT

PROJECTILE OBSERVER OR FDO WILL SELECT

AMMUNITIONLOT AND CHARGE COMPUTER WILLSELECT

FUZE OBSERVER OR FDOWILLSELECT

NUMBER OF ROUNDS FDO WILLANNOUNCE

RANGE SPREAD, LATERAL SPREAD, NOT UNLESS SPECIFIEDZONE FIRE,OR SWEEP FIRE,HIGH ANGLE

TIME OF OPENING FIRE WHEN READY

TARGET NUMBER NEXT AVAILABLE NUMBER



FM 6-40

Section IIFIRE COMMANDS

6-7. DEFINITIONFire commands are used by the FDC to give

the cannon sections all information needed tostart, conduct, and cease firing. They are sentto the section over the gun display units(GDU) in a battery operating with BCS or byvoice in a battery without BCS. The initialfire commands include all elements

necessary for orienting, loading, and firing.Subsequent fire commands include onlyelements that are changed except quadrantelevation, which is always announcedbecause it gives the howitzer sectionpermission to fire. Fire commands areannounced in sequence (table 6-3). Whetherthe battalion has GDUs or has voice only, thesequence of the fire commands is the same.

Table 6-3. Fire command elements.

6-6

WHEN ANNOUNCEDSEQUENCE OF ELEMENTS

INITIALFIRE SUBSEQUENT FIRECOMMAND COMMAND

1. WARNING ORDER ALWAYS NEVER

2. PIECES TO FOLLOW/ WHEN APPLICABLE WHEN CHANGED

PIECES TO FIRE'/ WHEN OTHERTHAN WHEN CHANGEDMETHOD OF FIRE STANDARD

3. SPECIAL INSTRUCTIONS

DO NOT LOADAT MY COMMANDHIGH ANGLEUSE GUNNER'S QUADRANTAZIMUTHSPECIAL CORRECTIONSSWEEP/ZONE FIRE

4. PROJECTILE' WHEN NOT STANDARD WHEN CHANGED

5. AMMUNITIONLOT' WHEN NOT STANDARD WHEN CHANGED

6. CHARGE ALWAYS WHEN CHANGED

7. FUZE'/FUZE SETTING' WHEN NOT STANDARD WHEN CHANGED

8. DEFLECTION ALWAYS WHEN CHANGED

9. QUADRANT ELEVATION ALWAYS ALWAYS

10. METHOD OF FIRE FOR EFFECT WHEN APPLICABLE WHEN CHANGED

'These elements may be designated as standard only if in the manual mode. Elements so designated will beannounced only when something other than standard is to be fired.



FM 6-40

6-8. FIRE COMMANDELEMENTS

a. Warning Order. A warning order isalways announced to alert the firing batteryto the mission. In a BCS battery, the warningorder is a steady alarm signal from the caseassembly of the GDU. The alarm indicatesthe start of the fire mission. When a firingbattery is using voice commands, a warningorder of FIRE MISSION will be announced.

b. Pieces to Follow/Pieces to FireMethod of Fire. Pieces to follow indicatesthose elements that will follow the missionand fire when called upon. In a GDU-equipped battery, the do not load (DNL)indicator bars will be lit on the section chief

assembly (SCA). This signifies that aparticular piece is to follow the mission andprepare to fire when commanded. Whenusing voice commands, the order BATTERYADJUST is given. This indicates that allweapons will copy the commands, follow themission, and eventually participate in the firefor effect. Pieces to fire/method of fireindicates the weapon(s) that will fire theinitial data and how many rounds (rd) to fire.On the SCA of the piece to fire, the displaywill read 1 RD ADJ and the double indicatorlights will be under the word FIRE. Voice

commands will be NUMBER 3, 1 ROUND.This indicates that only that piece will fireone round. If more than one weapon or theentire battery is selected to fire, eachweapon's SCA will have the FIRE indicatorbars lit, and the display will indicate thenumber of rounds (for example, 02RD FFE).A voice command of BATTERY, 2ROUNDS indicates that the entire batterywill fire two rounds.

c. Special Instructions. Specialinstructions are used when actions are

required that are different from normal.Within the BCS-equipped battery, restrictivecommands (DO NOT LOAD or AT MYCOMMAND) are signified by the doubleindicator bars under the DNL or AMC on thesection chief assembly. Other specialinstructions of HIGH ANGLE, GUNNER'SQUADRANT, AZIMUTH, or SWEEP/ZONE FIRE will be specified as a digitalreadout in the display window of the SCAafter the weapon's section chief presses thespecial instruction key. When using voice

commands, the FDC must announce theparticular special instruction(s) to be used.

(1) DO NOT LOAD is a restrictivecommand that prohibits loading and firing.It is used within the BCS/GDU battery or in

both the BCS/GDU and voice-commandedbatteries when it is anticipated thatsignificant time will elapse between loadingand firing. Cancellation of this command isindicated by the double indicator bars beinglit under the command FIRE in the displaywindow of the section chief assembly. Thevoice command is CANCEL DO NOTLOAD, QUADRANT (so much).

(2) AT MY COMMAND is a restrictivecommand that prohibits the battery fromfiring until directed to do so by the firedirection center. It is used during TOTmissions to ensure that all rounds impactsimultaneously. The guns fire when thealarm is heard and the double indicator barsare lit under the command FIRE. The voicecommand FIRE may also be used. Within thevoice-commanded battery, AT MY COM-MAND remains in effect until the commandCANCEL AT MY COMMAND is given.

(3) HIGH ANGLE is displayed orannounced to alert the crew that the missionis high angle.

(4) USE GUNNER'S QUADRANTis displayed or announced when the FDCdesires that the gunner's quadrant (GQ) beused.

(5) AZIMUTH is displayed or an-nounced to alert the guns to a large shift indirection of fire.

(6) SWEEP/ZONE FIRE is displayedor announced to alert the crew that themission is a sweep/zone mission.

(7) SPECIAL CORRECTION isdisplayed automatically as an individual firecommand to each firing piece in the BC Stechnical solution. It must be announced aspart of the voice fire commands when aseparate time, deflection, and/or quadrant ssent to one or more gun sections.

d. Projectile. The type of projectilethat is to be prepared and loaded is alwaysdisplayed in the section chief assembly.When voice fire commands are being used,

6-7



FM 6-40

the projectile must be announced when itdiffers from standard.

e. Ammunition Lot. Ammunition lotnumbers should be coded for simplicity.Separate-loading ammunition has two

designators-the first letter for the projectileand the second letter for the propellant.Semifixed ammunition has only a one-letterdesignation. The lot designators areautomatically displayed in the section chiefassembly. When voice fire commands arebeing used, the lot designators must beannounced when they differ from standard.

f. Charge. The amount of propellant tobe used is displayed automatically in thesection chief assembly. Charge must alwaysbe announced in initial voice fire commands.It is not standardized.

g. F u z e / F u z e Se t t ing . When aprojectile with a mechanical time (MT) orproximity fuze is fired, the computerdetermines a fuze setting that will cause thefuze to function at the desired point along thetrajectory. The fuze/fuze setting is displayedautomatically on the section chief assembly.Voice commands are announced as FUZETIME, TIME 17.6 or FUZE VT, TIME17.0.

h. Deflect ion. Deflection to fire isalways displayed in the SCA as a four-digitdeflection. In voice commands, deflection isalways announced as four digits; forexample, DEFLECTION 3245.

i. Quadrant Elevation. The quadrantelevation is displayed/announced in theinitial and all subsequent fire commands.The displayed/announced command (forexample, QUADRANT 309) is permissionfor the chief of section to load and fire theround unless otherwise restricted by specialinstructions.

j. Method of Fire For Effect. Themethod of fire for effect indicates the numberof rounds and types of ammunition to be usedin effect. This is displayed automatically inthe SCA. The method of fire for effect will beannounced by voice command after quadrantelevation (for example, 2 ROUNDS, FUZEVT IN EFFECT). This command allows thenonadjusting elements to prepare th eammunition for the fire-for-effect phase ofthe mission.

k. Special Methods of Fire. Specialmethods of fire include CONTINUOUSFIRE and FIRE AT WILL. These are voicecommands only and cannot be displayed onthe section chief assembly. However, sweepand/or zone fires, which are special methodsof fire, can be displayed on the SCA and canbe announced in voice commands.

6-9, STANDINGOPERATINGPROCEDURES

If no restriction has been imposed, unitSOP may allow loading when deflection isannounced. This is discouraged for self-propelled weapons, because the noise of therammer may keep the voice-announcedquadrant from being heard. Fire commandsfor special missions such as coordinatedillumination should be addressed by unitSOP according to the unit's level of training.

6-10, OTHER FIRECOMMANDS

a. Check Firing. The command

CHECK FIRING can be given by anyoneand will cause firing to cease immediately.This command will be used when all datahave been sent to the guns and an item mustbe changed. The SCA displays CHECKFIRE.

b. Cease Loading. The commandCEASE LOADING allows the firingbattery to fire rounds that are loaded, but noadditional rounds may be loaded. It is a voicecommand only, except in final protective fire(FPF) missions with the BCS.

c. End of Mission. The commandEND OF MISSION (EOM) means that thefire mission is terminated. The guns shouldreturn to the azimuth of lay (or priority targetdata). The SCA displays EOM.

d. Planned Targets. The battery maybe assigned planned targets for whichcurrent firing data must be maintained. TheFDC may designate targets as prioritytargets for the battery or for each platoon.

6-8

S



FM 6-40

Each target is assigned a number, and eachweapon is laid on its assigned priority target.In such cases, unit SOP usually designates acommand or prearranged signal to fire on thepriority target, bypassing the usual sequenceof fire commands. Assume target AC7343 hasbeen planned. On the command RIGHT,SUPPRESS AC7343, the right platoonengages target AC7343 with the previouslyarranged method of fire. In defensiveoperations, the command FIRE THEFINAL PROTECTIVE FIRES causes thefiring battery to fire the final protective fireson which it is laid.

6-11. REPORTSThe section chief reports to the FDC all

actions that affect the firing of his weapons

in support of the battery mission. Duringfiring, the following specific reports are madein a voice operation:

a. SHOT NUMBER (so-and-so) aftereach round has been fired.

b. ROUNDS COMPLETE NUMBER(so-and-so) when the final round has beenfired in effect.

c. MISFIRE NUMBER (so-and-so)when there has been a misfire.

d. Number of rounds expended by typeand lot number when requested by the FD C(voice only or per SOP).

e. Errors if any round has been fired withimproper data. The section chief reports tothe FDC the actual data fired in error; forexample, NUMBER 2 FIRED DEFLEC-TION (so much).

6-12. REPETITION ANDCORRECTION OF FIRECOMMANDS

a. One section of the firing battery shouldbe designated to read back all voice firecommands to ensure that the howitzersections have received the fire commandscorrectly. When a command has not beenheard or is misunderstood, the request forrepetition is stated as a question; for example,DEFLECTION NUMBER 3? When the

FDC replies, the repetition of commands isalways preceded by NUMBER (so-and-so),THE COMMAND WAS (for example,NUMBER 3, THE COMMAND WAS DE-FLECTION 2768).

b. If an incorrect command has beengiven but the command QUADRANT hasnot been announced, the FDC commandsCORRECTION followed by the correctcommand and all subsequent elements. IfQUADRANT has been announced, the FDCcommands CHECK FIRING. CANCELCHECK FIRING is announced followed bythe corrected element and all subsequentelements.

Section IIIMESSAGE TO OBSERVER

6-13. DEFINITIONAfter the manually equipped battery FDC

receives the call for fire, the FDO analyzes thetarget. If he decides to fire the target withartillery assets, he issues the fire order as hisdecision. That decision is announced to theobserver in the form of a message to observer.The message to observer consists of fouritems and is composed by the radiotelephoneoperator or is sent automatically by thebattery computer system.

a. Units to Fire-the battery or batteriesthat will fire the mission. The units areidentified by their radio call signs to theextent that they can be identified by theobserver. If a battalion is firing in effect withone battery adjusting, the message toobserver designates the fire-for-effect unit(battalion) and the adjusting unit (battery).

b. Changes to the Call for Fire-changes the observer needs to be informed ofthat have been made to his request for fire by

6-9



FM 6-40

the fire direction officer. That information ispassed to the observer in the second elementof the message to observer. For example, theobserver requests VT in effect, and the FDOdecides to fire DPICM in effect.The RATELOannounces T6H32, DPICM IN EFFECT.

c. Number of Rounds-the number ofvolleys in fire for effect. For example, theFDO decides to fire five rounds in effect. Heannounces T6H32, DPICM IN EFFECT, 5ROUNDS.

d. Target Number- the numberassigned to the mission for refer-ence purposes. For example, the nexttarget number is AD3476. The FDOannounces T6H32, DPICM IN EFFECT, 5ROUNDS, TARGET NUMBER AD3476.

6-14. ADDITIONALINFORMATION

a. Additional information may betransmitted with or following the message toobserver.

(1) If the probable error in range for anarea mission is greater than or equal to 38meters, the FDC will inform the observer. Ifthe probable error in range for a registrationis greater than 25 meters, the FDC will informthe observer.

(2) Angle T is sent to the observer whenit is greater than or equal to 500 mils or whenit is requested by the observer. Angle T isannounced to the observer to the nearest 100mils. For example, angle T is 580 mils. It isannounced as ANGLE T 600.

(3) The pulse repetition frequency for aCopperhead mission is sent when applicable;for example, PRF CODE 241.

(4) Time of flight is announced to thenearest second. It is announced to observerswhen targets are being engaged with shellCopperhead, when moving targets are beingengaged, or when time of flight is requested;for example, TIME OF FLIGHT 47. Time offlight is always announced to an air observer.

(5) If high angle is used, it is included inthe message to observer if the observer didnot request it.

(6) SPLASH may be sent at observer'srequest (mandatory for air observers andhigh-angle missions).

b. The BCU automatically generates astandard format message to observer. Thismessage to observer contains many itemsthat allow the receiving digital messagedevice (DMD) to establish a mission file. Seethe operator's manual or the job aids for adiscussion.

c. The messages to observer forregistrations are in the following format:

(1) The precision registration messageto observer is initiated in the FDC. It tells theobserver to register at a specific point (knownpoint or encoded coordinates) and gives fuzes

(point detonating [PD] and/or time) and theprobable error in range if it is greater than 25meters; for example, C8T16, THIS ISD2B23, REGISTER ON REGISTRA-TION POINT 1, QUICK AND TIME,OVER. The observer will report his directionto the FDC when he is ready to observe.

(2) The high-burst (HB)/MPIregistration message to observer is sent to theobserver(s) who will participate. It iscomposed in the following format:

(a) A warning order alerts theobservers to prepare to observe a certain typeof registration; for example, T2H13, T2H37,THIS IS B6H16, OBSERVE HIGH-BURST REGISTRATION.

(b) Orienting data to the orientingpoint (direction and vertical angle) forobserver 01 are sent; for example, 01DIRECTION 0510, VERTICAL ANGLE+16.

(c) 01 (or the single G/VLLD-equipped observer) is directed to measure the

vertical angle; for example, MEASURETHE VERTICAL ANGLE.

(d) Observer 02 (when applicable) isoriented to the orienting point; for example,0 2 DIRECTION 6130, VERTICALANGLE +6.

(e) The observers are directed toreport when they are ready to observe; forexample, REPORT WHEN READY TOOBSERVE.

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FM 6-40

Field artillery firing data are deter-mined by use of firing tables. These

firing tables contain the fire controlin format ion (FCI) for f i r ing unders t anda rd condi t ions and da t a fo r

correcting for nonstandardconditions.

The three types of firing tables are th et abu la r f i r ing tables , the graphicalf i r ing t ab les /graphica l f i r ing tablefans, and the graphical site tables. TheTFT is the base document. It containsfire control information in a tabularformat. The FCI is based on test firingsa n d c o m p u t e r s imu la t i ons o f th eammunition listed. The data listed arecorrected to standard conditions. TheGFT/GFT fan and the GST are graphical

representations of tabular firing tables.They expedite the computation of firingdata.

The Armies of the United States ,United Kingdom, and Australia and th e

Canadian Forces (ABCA) agree to usestandard tabular firing tables for th emanual preparation of firing data. Thisagreement is known as QSTAG 220.

The Armies of the United States an dher NATO allies agree to adopt th estandard firing tables format for NATOartillery cannons for the m a n u a lp r e p a r a t i o n o f f i r i ng data . Thisagreement is known as STANAG 4119.

Section IGRAPHICAL FIRING TABLES

7-1. MEANS OFDETERMINING FIRINGDATA

The GFT is developed from data in thetabular firing tables. It is used as anexpedient method of interpolating data fromthe tabular firing tables. Graphical firingtables are prepared for each weapon for mostshell families.

7-2. DESCRIPTION ANDUSE OF THE LOW-ANGLEGFT

Each GFT is printed on a rule that has acursor with an engraved fine hairline. The

cursor serves as the index for reading data.The hairline is perpendicular to the scales. Itis known as the manufacturer's hairline(MHL). The rule described in this section isthe HOW 155mm 155AM2HEM107CHARGE 4GB (fig 7-1).

a. Scales on the Low-Angle GFT. Thescales on each rule are drawn at a slant to thebase, angling from upper left to lower right.The scales appearing on the rule, from top tobottom, are as follows:

(1) Improved conventional muni-t ions scale. An improved conventionalmunitions (ICM) scale is on some graphicalfiring tables. It is located above the DEFLCORR/DRIFT scale. It consists of a QE scale

7-1



FM 6-40

Figure 7-1. Low-angle graphical firing table.

and a fuze setting (FS) scale. The QE scale isgraduated in mils, and the fuze setting scaleis graduated in fuze setting increments. TheICM scale applies to a specific type of ICM. Ithas the model number at the left end of thescale.

(2) Drift scale. The drift scale givesthe projectile drift correction (corr) in mils.This correction is always made to the left,since the projectile drifts to the right. EachHE elevation (el) at which drift changes(becomes 0.5 mil between the values) isprinted in red. Artillery expression is appliedto determine the value of drift at thatelevation. For example, at elevation 362, thedrift is actually 7.5, so it is applied as L8.

(3) 100/R scale. The 100/R scalegives the number of mils necessary to movethe burst laterally or vertically 100 meters atthe given range. These numbers are printedin red. The scale is based on the mil relationformula (;A = W/R).

(4) Range scale. The range scale isthe base scale, and all other scales are basedon it. Range is expressed logarithmically inmeters. The scale varies for each charge. Therange scale is developed to give as large a

range spread as possible and still permitgraduations large enough to be readaccurately. Range is read to the nearest 10meters.

(5) Elevation scale. The elevationscale is graduated in mils and is read to thenearest 1 mil. The numbers on this scale areprinted in red and black. The red numbersdenote the elevations that are within rangetransfer limits for a one-plot GFT setting.

(6) Fuze set t ing scale. The fuzesetting scale gives the fuze settings for timefuze M564 and is used for the time fuze M582without modification. The values are read tothe nearest 0.1 fuze setting increment. Thefuze setting scale is also used to determinetime of flight and VT fuze settings.

(7) A FS/ A 10M height-of-burstscale. The change to fuze setting that isnecessary for a 10-meter change in the heightof burst (HOB) is found on the AFS/ A10MHOB scale. This scale is read to the nearest0.01 fuze setting increment. It indicates theamount of correction that must be applied tothe M564 or M582 time fuze setting to raise orlower the height of burst 10 meters along thetrajectory.

7-2



FM 6-40

INote.n GFTs produced before 1983, afork scale is drawn. The fork scale is notused.

(8) Met check gage points. Abovethe fuze setting line, there are red triangulargage points. The apex of each triangle pointsto the quadrant elevation that, understandard conditions, results in the maximumordinate of the trajectory passing through awhole line number of a met message. Therange and quadrant elevation at the metcheck gage point are preferred forregistration aiming points, for met + VEcomputations, and for determination of GFTsettings.

(9) Height-of-burst probable errorgage points. Height-of-burst probableerror gage points are found on some GFTsabove the fork scale or on the FS scale. Theyare red right triangles. These gage pointsindicate the range and fuze settings at whichthe probable error in height of burst is 15meters. Larger height-of-burst dispersionmust be expected when a time fuze is usedwith a particular charge at a range exceedingthe gage point. Some charges have two suchgage points. The one on the left indicates the

range at which theprobable error in height of

burst for the next lower charge is 15 meters.

(10) Range probable er ror gagepoint. Above the A FS/ A 10M HOB scale,there is a black equilateral triangle. Thisgage point indicates the range at which therange probable error equals 25 meters. For allranges to the right of the gage point, rangeprobable error exceeds 25 meters.

(11) Range K line. The range K lineis a broken black line near the right edge ofthe rule. The angle that the range K line

makes with the scales geometrically portraysthe predicted rate at which range K varieswith range. An elevation gage line drawnparallel to the range K line for a one-plot GFTsetting provides elevation settings that varyat the same rate as does range K. The range Kline is ignored for multiplot GFT settings.

(12) Fuze K line. The fuze K line is abroken black line near the left edge of the rule.The angle that the fuze K line makes with thescales geometrically portrays the predicted

rate at which fuze K varies with range. A timegage line drawn parallel to the fuze K line fora one-plot GFT setting provides few settingsthat vary at the same rate as does fuze K. Thefuze K line is ignored for multiplot GFTsettings.

b. Fi r ing D a t a (No GFT Sett ing) .The procedure for determining the ele-vation and fuze setting with the conven-tional GFT when no corrections (no GFTsetting) are known is as follows:

(1) Place the MHL over the announcedchart range.

(2) Read the elevation under the MHLfrom the elevation scale.

(3) Read the fuze setting (M564 orM582) under the MHL from the fuze settingscale.

(4) Determine the VT fuze setting byreading the time on the fuze setting scalecorresponding to the elevation to be fired.Always express variable time as a wholevalue. Consequently, if the value read fromthe time scale is not a whole value, drop thetenths and express the value to the next lowerwhole value (for example, express 17.8 as17.0).

7-3. CONSTRUCTION OFGFT SETTINGS

a. The GFT setting is used to applycorrections for nonstandard conditions. Thecorrections are determined by firing,determined by met +VE, or inferred from thecomputer. The preferred GFT setting is themultiplot (the one with three or more sets ofcorrections) (fig 7-2). The alternate one-plotGFT setting should be used only if the unitdoes not have access to a computer or has notfired several registrations with the samecharge. The elements of each GFT setting are

always expressed and recorded in thefollowing sequence:(1) Unit for which the GFT setting is

prepared (for example, GFT A).(2) Charge (for example, Chg 5).

(3) Ammunition lot (for example, LotXY).

S(4) GFT setting range (chart range orachieved range used in computing the GFTsetting) (for example, Rg 4860).

7-3



FM 6-40

Figure 7-2. Multiplot graphical firing table setting.

(5) Adjusted elevation (for example, El222).

(6) Adjusted time (for example, Ti 14.6).(7) Deflection correction (for example,

Total [Tot] Df Corr: L8; GFT Df Corr: L3).b. There are no range limits for a

multiplot GFT setting. To apply a multiplotGFT setting (preferred), use the followingprocedures (fig 7-2):

(1) Slide the cursor until the MHL isexactly over the GFT range on the rangescale.

(2) Using a soft-lead pencil, place a do ton the cursor at the adjusted elevation alongthe elevation scale.

(3) Place a second dot on the cursor atthe adjusted time along the M564 fuze settingscale.

(4) Repeat these steps for all sets ofcorrections until all the data have beenrecorded.

(5) Using a straightedge and asoft-lead pencil, connect all the elevationdots, and label the line segment EL. Connectthe time dots, and label the line segment TI.

(6) Check the GFT setting by slidingthe cursor back to the ranges for the sets of

corrections, and read the data plotted for eachrange.

(7) Take the average of the totaldeflection corrections, and record it on theupper left portion of the cursor and draw acircle around it. Take the average of the GFTdeflection corrections, and record it on theupper right portion of the cursor.

c. To apply a one-plot GFT setting (fig7-3), use procedures in b(1) through (3) aboveand slide the elevation dot over the RG K line.Trace the line and label it EL. Also, slide thecursor until the time dot is over the FZ K line.Trace the fuze K line and label it TI. Slide thecursor back over the GFT range, and read theoriginal set of data. Apply the total deflectioncorrection on the upper left portion of thecursor and draw a circle around it. Record thevalue of the GFT deflection correction on the

upper right portion of the cursor.

7-4. DETERMINATION OFFIRING DATA BY USE OFTHE GFT SETTING

a. Reading the GFT Scales.

(1) Improved conventional muni-tions scale. Slide the cursor until the MHL

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FM 6-40

Figure 7-3. One-plot graphical firing table setting.

is over the HE (or base projectile) quadrantelevation on the elevation scale. Read theICM QE under the MHL on the ICM scale. Todetermine the ICM fuze setting, place theMHL over the M564/M582 fuze setting andread the ICM time under the MHL on the ICMfuze setting scale. See chapter 9, section I, forinstructions on the use of this scale.

(2) Drift scale. Move the cursor untilthe MHL is over the range. Read drift underan imaginary line that is parallel to the MHLand crosses the elevation gage line at theelevation scale. Drift can also be read byplacing the MHL over the elevationdetermined and reading the value of driftunder the MHL. Drift is a function ofelevation but cannot be read directly underthe elevation gage line.

(3) 100/R scale. 100/R is a functionof range and is read under the manufacturer'shairline. Since it is based on the mil relation,100/R is unaffected by corrections fornonstandard conditions, charge, projectile,or caliber.

(4) Range scale. Slide the cursoruntil the MHL is over the range on the rangescale. The range scale is the base scale of thegraphical firing table.

(5) Elevation scale. Slide the cursoruntil the MHL is over the range on the rangescale. Read the elevation under the elevationgage line where it crosses the elevation scale.

(6) Fuze setting scale. Read the

time to be set on the M564/M582 fuze underthe TI gage line where it crosses the fuzesetting scale.

(7) Fork scale. Not used.

(8) A FS/ A10M HOB scale. A FS isa function of fuze setting but cannot be readunder the time gage line. It is read on theA FS/ A lOM HOB scale under an imaginaryline that is parallel to the MHL and crossesthe fuze setting scale at the same point as thetime gage line. It can also be determined byplacing the MHL over the fuze settingdetermined and reading A FS/ A 10M HOBunder the manufacturer's hairline.

(9) Variable time fuze setting or timeof flight. Variable time fuze setting or timeof flight is a function of elevation but cannotbe read under the elevation gage line. Read iton the M564/M582 fuze setting scale underan imaginary line that is parallel to the MHLand crosses the elevation scale at the samepoint as the elevation gage line. After reading

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FM 6-40

a value from the M564/M582 fuze settingscale, determine the VT fuze setting bydropping the tenths of a fuze settingincrement. Also determine the VT fuzesetting by moving the MHL to the elevationdetermined, reading the fuze setting from the

FS scale, and dropping the tenths of a fuze,setting increment.

b. Reading the GFT Settings. Figure7-4 graphically displays the correctprocedure for reading firing data from thegraphical firing table.

Figure 7-4. Reading graphical firing table.

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FM 6-40

Section IIGRAPHICAL FIRING TABLE FAN

7-5. DESCRIPTIONThe GFT fan is a range-deflection

protractor modified to hold a ballistictemplate over the arm (fig 7-5). The ballistictemplate has a series of scales for eachcharge. Only the best ranges for each chargeare listed on the GFT fan. Once a target isplotted on the firing chart, the chart operatorcan determine and announce firing data tothe target for a center-of-battery tocenter-oftarget solution.

a. Range Scale. The range scale is the

base scale of the GFT fan. It runs along theleft edge of the ballistic template andcorresponds to the ranges etched on therange-deflection protractor. It is graduatedin the same manner as the range-deflectionprotractor. Range can be read to an accuracyof 10 meters under the MHL on the cursor.

b. Charge. The GFT fan may listseveral charges that could be fired at thechart range. The charge selected to fireshould have at least 500 meters over andshort in range to allow for observer

adjustment.c. Elevation Scale. Along the right

edge of each charge ballistic scale is theelevation scale. It is graduated every 5 milsand labeled every 50 mils. Elevation isvisually interpolated to the nearest 1 mil.

d. Fuze Setting Scale (M564). Alongthe left edge of each charge ballistic scale isthe M564 time fuze setting scale. This scale isgraduated every whole fuze setting incrementand labeled every 5 whole fuze settingincrements. Fuze setting is visually

interpolated to the nearest 0.1 fuze settingincrement.

e. Drift Scale. The drift scale is to theright of the charge elevation scale. It is readin the same manner as the drift scale on thegraphical firing table.

f. 1 OO/R Scale. The 100/R scale isalong the right edge of the ballistic template.It is read in the same manner as the 100/Rscale on the graphical firing table.

Figure 7-5. Graphical firing table fan.

g. A FS/ A 1 OM HOB Scale. Thisscale is not found on the GFT fan. Use theTFT or GFT to determine this value.

7-6. CONSTRUCTION OFA GFT SETTINGON A GFT FAN

Use a multiplot GFT setting if available.The procedure for applying a multiplot GFTsetting is the same as that described inparagraph 7-3b. If only one plot is available,construct the GFT setting on the GFT fan byuse of the following procedure:

GFT A: Chg 4, Lot XY, Rg 5000, El 316, Ti19.3; GFT Df Corr: L2, Tot Df Corr: L8.

a. Construct the GFT setting on thegraphical firing table.

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FM 6-40

Lote. If several cursors are available(NSN 5355-01-076-5554), place only oneGFT setting per charge on each cursor.

b. Slide the cursor of the GFT fan untilthe MHL is over the range of 5,000 meters onthe range scale.

c. Using a soft-lead pencil, place a doton the cursor of the GFT over elevation 316 ofthe charge 4 elevation scale.

d. Place a second dot on the cursor atthe GFT time of 19.3 along the charge 4 M564fuze setting scale.

e. On the charge 4 GFT, slide the cursoruntil the MHL is over met check gage point

range 3730 (a met check gage pointrepresenting the same line number used inthe registration). Read the correspondingelevation (221) under the elevation gage lineand the fuze setting (13.7) under the time gageline.

f. Slide the cursor of the GFT fan untilthe met check gage point range 3730 is underthe manufacturer's hairline. Place dotscorresponding to the met check gage point ELand TI as above.

g. The GFT fan cursor now has fourdots on it. It has two elevation dots and twofuze setting dots. With a straightedge, draw aline through the elevation dots. Do the samewith the fuze setting dots. These linesrepresent the elevation and time gage linesand are parallel to the RG K and FZ K lines ofthe graphical firing table. Label these linesEL and TI respectively.

h. Place the GFT deflection correctionon the upper right-hand corner of the cursor.

Place the total deflection correction on theupper left-hand corner of the cursor.

7-7. DETERMINATIONOF FIRING DATAWITH THE GFT FAN

The GFT fan can be used by the chartoperator to determine all manual firing data.

a. Charge. Once the target is plottedand the fan aligned with it, the operator canannounce the optimum charge for themission.

b. Fuze Setting. If a time or proximity

fuze is designated in the fire order, the fuzesetting is determined and announced.

c. Deflection. Two brief mentalcomputations are required of the operator todetermine deflection.

(1) First, the operator must determinethe deflection correction by applying the GFTdeflection correction (average) to drift.

(2) Then, the operator must apply thiscorrection to the chart deflection to get thedeflection to fire.

d. Site. The VCO determines site.e. Quadrant Elevation. The operator

reads elevation from the GFT fan and appliessite. He then announces quadrant elevation.The site used may be an average site or on ecomputed with the graphical site table.

f. 20/R. If an airburst is required, 20/Rmust be determined and applied to thequadrant elevation. When M728 fuzes arefired, 20/R is not applied.

Section IIITABULAR FIRING TABLES

7-8. STANDARDSTabular firing tables are based on the test

firing and computer simulations of a weapon

and its ammunition correlated to a set ofconditions that is defined and accepted asstandard. These standards are points Ofdeparture. Corrections are used to

7-8

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FM 6-40

compensate for variables in the weather/weapon/ammunition combination that areknown to exist at a given instant andlocation. The atmospheric standardsaccepted in US firing tables reflect the meanannual condition in the North TemperateZone.

7-9. ELEMENTS ANDPURPOSE OF THE TFT

a. The principal elements measured inexperimental firings include angle ofelevation, angle of departure, muzzlevelocity, achieved range, drift, and currentatmospheric conditions.

b. The main purpose of a TFT is toprovide the data to bring effective fire on atarget under any set of conditions. Data forfiring tables are obtained from firingsconducted with a weapon at variousquadrant elevations. Computed trajectories

based on the equation of motion arecompared with the data obtained in thefirings. The computed trajectories are thenadjusted to the measured results and data aretabulated. Data for elevations not fired aredetermined by interpolation. Firing tabledata define the performance of a projectile ofknown properties under conditions ofstandard muzzle velocity, standard weather,and a motionless earth. The introduction ofeach TFT describes its contents and use.

Section IVGRAPHICAL SITE TABLES

7-10. DESCRIPTIONa. Advantages of the GST. The GST

was developed to provide a quick, accuratecomputation of vertical angle, angle of site,and site. The GST can also be used to computeVI when the site, charge, and range areknown; when the angle of site and range areknown; or when the vertical angle anddistance are known. The GST includes ameans for converting yards to meters ormeters to yards without any additional

movement of the slide or cursor. Each GST isdesigned for a particular weapon, and sitecomputations are valid only for the weaponspecified on the graphical site table. Whenangle of site is greater than ±100 mils, theGST cannot be used to compute site.

b. Components of the GST. The GSTdescribed in this section is GST HOW 155mm, FT 155-AM-2, PROJ HEM107. The GSTconsists of a base, a slide, and a cursor (fig7-6).

Figure 7-6. Graphical site table.

7-9

0

MOW155mmS036W0do 6200TAG 4FT 155-AM-2 4GB TA801 f ' 4PROJ HEMIOT Tb55_'--_, , ".- ,. b_AG e6o3,,0 0....9o& TAG

14'fou

FT77WB -ow3GBWB - 14

o Imo.



FM 6-40

(1) Base. The base is marked with theD-scale (site and VI). The marking of theD-scale is identical to that of the logarithmicD-scale of the military slide rule. This scalerepresents the values of VI, vertical angle,angle of site, and site.

(2) Slide. The slide is marked with aC-scale, gage points, and site-range scales.

(a) C-scale. The C-scale (range) isused with the D-scale to performmultiplication and division. The C- andD-scales and the M-gage point are used forcomputing VI, vertical angle, and angle ofsite.

(b) Gage points. The C-scale is alsomarked with meter (M) and yard (YD) gagepoints. The M gage point is used to multiplythe value opposite the C-index by 1.0186.This procedure gives an immediate andprecise solution to the mil relation (A - 1.0186W/R). Use of the M gage point is requiredwhen the VI and range are in the same unit ofmeasure. The YD gage point is used tomultiply the value opposite the M-gage pointby 0.9144. This procedure gives an immediatesolution to the formula YARDS x 0.9144-METERS.

(c) Site-range scales. The site-range scales are used to compute site whenthe VI and range are known or to compute theVI when the site and range are known. Foreach charge indicated, there are two site-range scales-one is black, marked TAG(target above gun), and the other is red,marked TBG (target below gun). Each scale isplaced in relation to the M-gage point so thatsite is read on the D-scale opposite the M-gagepoint when VI on the D-scale is divided byrange on the site-range scale. The TAG andTBG scales are constructed to include compsite. They differ from each other just as thecomp site factor for a plus angle of site differsfrom the comp site factor for a minus angle ofsite. The TAG scale is used when the VI or siteis plus, and the TBG scale is used when the VIor site is minus. The value of site is read orplaced opposite the M-gage point.

(3) Cursor. The cursor has a verticalhairline and serves the same purpose as theindicator of a military slide rule; that is, itenables the user to place or read a value on theslide opposite another value on the base.

c. Range Changeover Point. On allGSTs for all charges there is a point on allTAG and TBG scales where the scales beginto "double back"; that is, the cursor is movedto the left rather than to the right for anincrease in range for a given vertical interval.The range at which each scale reversesdirection is called the range changeoverpoint. The location of the changeover pointcan be shown by plotting site as a function ofsite in mils and range in meters. Remember,site equals the angle of site plus comp site. Infigure 7-7 at the lower ranges (5,000 to 7,000meters), the angle of site is decreasing morethan comp site is increasing; thus, sitedecreases. At the longer ranges (8,000 to 9,000meters), the angle of site is decreasing lessthan the comp site is increasing; thus, siteincreases. The site curve shows decreasingvalues up to a range of approximately 7,600meters and then shows increasing valuesbeyond. The range at which site is anabsolute minimum value is 7,600 meters andis thus the range changeover point.

12

10

8MILS ANGLE OF SITE

6 q

4

2=COMP ANGLE OF SITE

5000 6000 7000 8000 9000

RANGE (METERS)

Figure 7-7. Range changeover point,charge 4 GB .

7-11. DETERMINATIONOF VERTICALINTERVAL

When the altitude of the target isdetermined and the altitude of the battery is

7-10



FM 6-40

known, the next step is to compute the VI(difference in altitude between the batteryand the target). The altitude of the battery isalways subtracted algebraically from thealtitude of the target. The VI is computed to1-meter accuracy and must be expressed asplus or minus. For example, if the batteryaltitude is 376 meters and the target altitudeis 354 meters, the VI is -22 meters (354 - 376).A VI can also be computed in reference to anobservation post by algebraicallysubtracting the altitude of the observationpost from the altitude of the target. If thedesired point of burst is to be at an altitudeother than the target altitude, the VI iscomputed to the burst altitude instead of thetarget altitude.

Note. The above computation is notperformed on the GST.

7-12. COMPUTATIONS WITHTHE GST

a. Multiplication and Division. Thescales are read and multiplication, division,

and rough computation for the decimal pointlocation are performed on the GST in thesame manner as they are on the military sliderule.

b. Computation of Angle of Site. Forcomputation of angle of site, the range to thenearest 10 meters and the VI to the nearestmeter are used. The answer is read oppositethe M gage point to the nearest 1 mil.

(1) Move the hairline over the VI valueon the vertical interval (D) scale.

(2) By moving the slide, set the range tothe nearest 10 meters on the range (C) scaleunder the hairline.

(3) Read the value opposite the M gagepoint on the D-scale. Determine the decimalpoint location by making the value of theangle as large as possible without exceedingthe value of the vertical interval. Express theresult to the nearest mil for the angle of site,which must have the same sign as that of thevertical interval.

EXAMPLE:The VI is +37 meters and the range is 5,460meters. To compute the angle of site, movethe hairline over 37 on the D-scale. Move theslide until 5460 on the C-scale is under thehairline. Read 691 opposite the Mgage point.The largest value that does not exceed 37 is6.91. The VI is plus; therefore, the angle ofsite is +6.91 expressed as +7 mils (fig 7-8).

RANGE 5460

C-SCALED-SCALE

VERTICALINTERVAL +3 7

ANGLE OF SITE+6.91 +7 MILS

Figure 7-8. Graphical site table position forangle of site for a verticalinterval of +37 at a range of5,460 meters.

c. Computation of VerticalAngle. Avertical angle is computed in the same

manner as an angle of site.d. Computation of Site. To compute

site, use the appropriate site-range scaleinstead of the range (C) scale so that compsite is automatically added to angle of site.

(1) Move the hairline over the VI valueon the vertical interval (D) scale.

(2) By moving the slide, set the range tothe nearest 10 meters on the appropriatesite-range scale under the hairline.

7-11



FM 6-40

(3) Read the value opposite the M-gagepoint. Determine the decimal point location,express the result to the nearest 1 mil, and usethe same sign as that of the vertical interval.

EXAMPLE:The VI is +37 meters and the range is 5,480meters. Charge 4GB GST 155-AM-2 is used.To compute the site, move the hairline over37 on the D-scale. Move the slide until range5480 on the site-range scale (chg 4, TAG) isunder the hairline. Read 788 opposite the Mgage point. Site is +8 mils (+37 1 5 roughdivision). See figure 7-9.

RANGE 5480, CHARGE 4, TARGET ABOVE GUN

Figure 7-9. Graphical site table position forcomputing site for a verticalinterval of =37 at a range of5,480 meters.

e. Computation of Comp Site. Compsite can be computed to the nearest one tenth

mil by use of the graphical site table.(1) Compute the angle of site to the

nearest 0.1 mil.

(2) Compute the site to the nearest 0.1mil.

(3) Algebraically subtract the angle ofsite from site.

(4) The remainder, with its sign, iscomp site to the nearest 0.1 mil.

EXAMPLE:VI is +37 meters and range is 5,480 meters.Charge 4GB GST155-AM-2 is used. Angle ofsite is +6.9 mils. Site is +7.9 mils. Therefore,comp site is (+7.9) - (+6.9) = 1.0 mil.

f. Computation of Vertical In terval .The VI can be computed with the GST by areverse procedure (multiplication by use ofthe formula VI = #iR) when the angle of site,site, range or distance, charge, and weaponare known.

(1) Move the slide until the M-gagepoint is opposite the value of the angle (angleof site, vertical angle, or site) on the D-scale.

(2) Move the hairline over the range (tothe nearest 10 meters) on the C-scale whenangle of site or vertical angle is known and onthe appropriate site-range scale when site isknown.

(3) Read the value under the hairline onthe D-scale. Determine the decimal pointlocation, express the result to the nearest 1meter, and affix the same sign as that of theangle.

EXAMPLE:Site, range, and charge are known. The site is+5 mils and the range is 4,650 meters. Charge4GB GST 155-AM-2 is used. Compute thevertical interval. Move the slide until the Mgage point is opposite Son the D-scale. Movethe hairline over range 4650 on the charge 4TAG site-range scale. Read 211 under thehairline on the D-scale. The VI is therefore+21 meters ([+5] x [4.65).

g. Limitations of the GST. The angleof site limitation for use of the GST is ±100mils, because at this point, the mil relationbegins to break down, and an error exceeding1 mil is introduced. When the angle of siteexceeds ±100 mils, use the following formulaTan ,4 site = VI/R.

EXAMPLE:Vertical interval = 600 metersChart range = 5,000 metersTan 2 site = 600 - 5000 = 0.120004f site tan 0.12 (TM 6-230, table IV) = 122mils

7-12

VERTICAL INTERVAL+37



FM 6-40

Then compute site as described in paragraph7-15. If the limitations are not exceeded, themaximum error in computations obtainedwith the GST will not exceed 1 mil.

7-13. DETERMINATION OFANGLE OF SITE ANDVERTICAL ANGLEWITHOUT A GST

a. Angle o f Site and Vertical AngleLess Than ±100 Mils.

(1) Angle of site. When the VI andchart range are known, the angle of site isdetermined by mil relation ('A = W/R) where1-As the angle of site, W is the VI, in meters,between the piece and the target or point of

burst, and R is the range to the nearest 100meters, expressed in thousands. For example,range 4,060 is expressed as 4.1. Angle of site iscomputed to the nearest one tenth mil. Theangle of site is a signed value and has thesame sign as the VI. The angle of site is pluswhen the target is above the piece. It is minuswhen the target is below the piece.

EXAMPLE:FT 155-AM-2, charge 4GB, is used. Batteryaltitude is 431 meters. The following call forfire is received:

ADJUST FIRE, SHIFT AF7821, OVER.DIRECTION 5710, RIGHT 200, ADD700, DOWN 30.

The chart range to the plotted target location

is 4,790 meters. Compute the angle of site.

Computation of target altitude:

Target AF7821Subtract 30 (observer'sDOWN 30)

Target altitude

451 meters

-30 meters

421 meters

Computation of VI and angle of site:

Target altitude 421 metersSubtract battery altitude -431 meters

Vertical interval -10 meters

Angle of site = VI/R = 10/4.8 = -2.08, or -2.1mils.

The angle of site is minus, because thetarget altitude is lower than the batteryaltitude.

(2) Vertical angle. Vertical angle iscomputed in the same manner as angle ofsite, except the observer altitude and distanceto the target are used instead of the batteryaltitude and gun-target range.

b. Angle of Site and Vertical AngleGreater Than ±100 Mils.

(1) Angle of site. An angle of sitegreater than +100 mils must be computed byuse of the formula Tan 4 site = VI/R.

(2) Vertical angle. A vertical anglegreater than ±100 mils is computed in thesame manner as angle of site greater than±100 mils.

7-14. DETERMINATIONOF VERTICALINTERVALWITHOUT A GST

The VI can be computed (VI =OR) when theangle of site and range or the vertical angleand distance are known.

EXAMPLE:An observer desires to determine the altitudeof a target. The altitude of the OP is 263

meters. The vertical angle from the OP to thetarget is -4 mils. The estimated distancefrom the OP to the target is 1,600 meters.Compute the target altitude. Computation ofVI and target altitude is as follows:

Distance to target,in thousands 1.6Multiplied by thevertical angle x (-4) mils

VIOP altitudeAdd VI

Target altitude

-6.4, = -6 meters

263 meters

+ (-6) meters

257 meters

7-15. DETERMINATION OFCOMPLEMENTARYANGLE OF SITEWITHOUT A GST

a. The complementary angle of site iscomputed by multiplying a plus (minus)

7-13



FM 6-40

angle of site times the value of thecomplementary angle of site for a plus(minus) 1-mil angle of site. This value isfound in column 12 (or 13) of thesupplementary data table (table G) of thetabular firing table and is commonly calledthe comp site factor. The comp site factormust be determined by interpolation of thechart range to the nearest 100 meters. Compsite, which is computed to 0.1 mil, is a signedquantity taking the sign of the comp sitefactor.

b. A study of listed values for the compsite factor reveals that for short ranges, thecomp site factor is negligible. As the rangeincreases, the factor increases for any givencharge. Thus, at greater ranges, the comp sitefactor is significant, even for small angles of

site. The comp site factor also varies with thecharge for any given range.

EXAMPLE 1:FT 155-AM-2, charge 4GB, is used. Chartrange is 5,000 meters and angle of site is +7.1mils (target above battery position).Compute the comp site.

Computation of site:

Comp site factor for a +1 mil angle of site,range 5000 (table G, column 12, TFT155-AM-2)

+0.103 milMultiplied byangle of site

Comp site

x 7.1 mils

+0.7313, +0.7 mil

EXAMPLE:FT 155-AM-2, charge 4GB, is used. Batteryaltitude is 270 meters, target altitude is 301meters, and chart range is 4,710 meters.Compute the site.

Computation of VI:

Target altitudeSubtract batteryaltitude

301 meters-270 meters

VI + 31 meters

Computation of angle of site = (+31)+ (4.710)=+6.6Computation of comp site = (0.086) x (6.6)=+0.5676 z+0.6Computation of site = +0.6) + +6.6)= +7.22.+7

7-17. AVERAGE SITEa. A considerable amount of time can be

saved in mission processing if average sitecan be precomputed for the area ofoperations.

b. As time permits, the VCO develops acolor-coded average altitude map (fig 7-10).He then determines average site to eachcolor-coded band.

c. This technique may not be practical incer ta in si tuat ions; for example, inmountainous terrain or in fast-movingsituations where the VCO could use thealtitude of the nearest replotted target. Ifspeed is essential, the FDO can announceIGNORE SITE in the fire order.

EXAMPLE 2:FT 155-AM-2, charge 4GB, is used. Chartrange is 6,500 meters and angle of site is -1.2mils (target below battery position).Compute the comp site. Computation of thecomp site factor for a -1 mil angle of site(table G, column 13, TFT 155-AM-2) is-0.238. Comp site is -0.3 mil.

7-16. DETERMINATION OFSITE WITHOUT A GST

Site is the algebraic sum of angle of site andcomp site. Site is a signed value and isexpressed to the nearest 1 mil.

S + TSITE +3 ALTITUDE 390

111,1,10,1 SITE +4 ALTITUDE 420

Figure 7-10. The average altitudemap (color coded and markedwith average site).

7-14



FM 6-40

n many instances, fire-for-effectdata may not reflect the actual loca-

tion of the target as defined by its chartcoordinates and altitude. This inac-

curacy results from errors in initialtarget location and errors in deter-mining the initial site fired in an adjustf i re miss ion . For the observer toaccurately shift from a known pointlocated by replot or for other units tomass fires on the same point, the actualtarget location and altitude must bedetermined as accurately as possible. Todo this, the replot process is used.

a. Replot gives a deflect ion andrange with which the actual target

location can be polar plotted from th elocat ion of the f i r ing ba t te ry. Themanual replot procedures for pointdetonating (PD) and VT fuzes are th e

same.The procedures for a time fuze are

s o m e w h a t d i ff e r en t . Targe t s a rereplotted on request of the observer orthe fire support officer or when directedby the fire direction officer.

b. At times, an observer is unable tolocate a target accurately. Inaccuratet a rg e t l o c a t i o n m a y r e su l t in aninaccurate altitude and an inaccuratesi te be ing d e t e r m i n e d by the firedirection center. For example (fig 8-1), ifthe observer locates a target at a higher

Figure 8-1. Second target location.

8-1



FM 6-40

altitude than that of the actual target,site is determined on the basis of anincorrect altitude. The observer sends acorrection of DROP 400. The data arecomputed to cause the round to impact atpoint A, because no adjustment has beenm a d e to altitude T h e p r o j e c t i l econtinues and impacts over the target.In figure 8-2, it can be seen that with th eobserver 's next correction (DROP 50),accurate fire for effect is obtained. It canalso be seen that there is a differencebetween the final pin location on th ef i r ing cha r t and the ac tua l t a rge tlocation. Target replot is required tocorrect for this error. Replot proceduresuse successive approximation for fuzes

quick and variable time to determine th etrue site and the actual (replot) rangeand deflection to the target.

c. To replot a target accurately, amap, accurate refinement data from th eobserver, and a valid GFT setting arerequired by the fire direction center. Avalid GFT setting is one that accuratelyportrays the corrections for nonstand-ard conditions at the time the missionwas fired. The GFT settings may proveto be inval id because of w e a t h e rchanges or survey errors. If a valid GFTse t t i ng fo r the t ime o f f i r i ng isdetermined, it is used to replot th etarget.

Figure 8-2. Observer's final correction.

Section IMANUAL PROCEDURES

8-1. POINT-DETONATINGAND VARIABLE TIMEFUZE (M728) REPLOT

a. Replot Deflection. The replot (true)deflection to the target may or may not be the

final piece deflection. Because drift may havechanged dur ing the conduct of th eadjustment , the true total deflectioncorrection is determined as follows:

(1) After determining final piece datafrom the observer's refinement, determine thefirst apparent elevation.

8-2



(2) Determine drift corresponding tothe first apparent elevation.

(3) Add the drift, determined in thesame manner as in (2) above, to the GFTdeflection correction. The resulting data arethe true total deflection correction. Thendetermine the replot deflection bysubtracting the true total deflectioncorrection from the final piece deflection.

b. Replot Grid and Altitude. Thereplot grid and altitude are determined bysuccessive approximation. The proceduresare described below.

(1) To determine the first apparentelevation, the battery computer subtracts sitefrom the final quadrant. The computerdetermines the replot deflection as outlined inparagraph a above and announces it to thehorizontal control operator. The computerthen determines the range corresponding tothe first apparent elevation. He reads therange under the MHL where the elevationgage line is placed on the first apparentelevation and announces this range to thehorizontal control operator.

(2) The HCO polar plots the target fromthe battery center at the deflection and rangeannounced by the computer and announcesthe plotted grid to the vertical controloperator.

(3) The VCO plots the grid anddetermines the map altitude at the replottedlocation. Using the new altitude and therange last announced by the computer, theVCO computes the first apparent site andannounces it to the computer.

(4) The computer determines if the firstapparent site is within ±1 mil of the lastcomputed site fired.

(a) If the first apparent site is within±1 mil of the last computed site fired, the siteis considered true site. To determine trueelevation, the computer subtracts the true sitefrom the final quadrant. Using the proceduredescribed in (1) above, the computerdetermines the replot range. The replotdeflection remains the same throughout theprocess of successive approximation. Thecomputer announces the final replotdeflection and range to the horizontal controloperator. The HCO announces the replot gridto the computer. The VCO announces the

RECORD OF FIRE

CALL OR FIRE TGT 380 GFT R 5 A FSObserver G H - 3 AF(SIS/S Tgt 37-R Y 35 5 DFT L5 I01- 26

Grid: Vl 2IPolar:Dir Dis U/D VA

Shift A,7O 5 0 Dir 0 54-O L5 0 2 0 0 U/D 0/ 5.4 Si-io J si NOBCorr

FIRE RDER A MOC DfCorr 0 S + 7INITIALFIRE OMMANDS MF.... : . Rg.360Ch...30 El 2~

Sp Ins r SPEC CORR AMC, .h .LotChg FzVT Ti f GEMTO J(

0)4TITF in Eff Ammo xI

Tgt Location riority Firing SUBSEQUENTIRE OMMANDSnit L.T

Dir, MF DeM Rg NOB MF, Sh, FS Chart Df Corr Df Chart NOB Si Typ

Sh, Fz Corr Chg, z Corr Ti Df ( ) Fired Rg Corr ( El QE Exp Type

_________ F5 3209 L30 i - I 250 0

____ ,,,, ,ir __ O 3 20o9 R 8 32. , _ o ,o.. . . ...................... :v :ii:i:i: :i:ii :ii::i:l:::i__L PT _ 209 R38 017?

R3 1REC B,I7 3 ) 5 * 0 5 o t7 249 i

A5ToT, E O M ' EST 1t . . . . . . . . . . . . . . . . . . . . . . . . .

, ...... ... ....... . . . . . . . . . . . . . . . . . . . . . . . .........: : :

,: : - . . . ..... . ... ........... ::.. .:.:. :... ::::.. :::::.- -. . . . . . . ........ .... .... .......:..:..'::.-.::..................... i~~~~ii ii..iii F .....................

CM PrT -j HCO .............. 1-A:X::MCO __VCQ

Wg~-~DVCQ Cr ..............CMPI OA_1_51 S -fCO

RC .......-..........

HC0 CM TR REpLOTR &NCO 41A

Btry DTG, 5/ ;*-3 TtAA7O60 ReplotGrid 61 163660 IR, otA'tZ56O

REPLACES A FORM 504, I MAY76 , WHICN SOBSOLETE FOR SE F HIS ORM, EE 6-40;THE ROPONENTGENCYSTRADOC

altitude used to determine true site. Thisaltitude is replot altitude.

(b) If the site is not within ±1 mil of thelast computed site, the steps in (1) through (3)above are repeated until a true site isdetermined that agrees within ±1 mil of thelast computed site. A completed record of fireis in figure 8-3. Table 8-1 is an example of areplot mission (proximity fuze [M728]).

EXAMPLE:Given: M109A3 (FT 155-AM-2)GFT B: Chg 4, Lot XY, Rg 5270, El 350, Ti19.9Tot Df Corr: L2; GFT Df Corr: R5

8-

FORM 4504DA 1OCT 7 8 4 5

Figure 8-3. Completed record of fire-proximity fuze (M728).

8-3



-40

Table 8-1. Example of replot mission-proximity fuze (M728).

HORIZONTAL VERTICALCONTROL CONTROL

STEP COMPUTER OPERATOR OPERATOR

Determines first apparent elevation:Final QE (256) - site fired (+7) = 249

Determines total replot deflection correction:GFT deflection correction (R5) + drift correspond-ing to the first apparent elevation (L5) = 0

Determines replot deflection:Total replot deflection correction (0) - final piece

deflection (3187) = 3187

Determines range:Range corresponding to first apparentelevation 249 = 4050

2

3

4

5

6

7

31874130

Determines that the site determined is not within+1 mil of previous site fired; it is not the true site.Determines second apparent elevation:Final QE (256) - first apparent site (0)- 256Determines and announces replot range:Range corresponding to elevation 256 = 4140Announces:REPLOTDEFLECTION 3187RANGE 4140

Polar plots grid.

Measures andannouncesgrid to VCO:GRID 61163651

Polar plots rangeand deflection;measures andannouncesREPLOT GRID:

Plots grid.

Determines altitude:Altitude 355Determines verticalinterval:VI = 355 - 355 = 0

Computes first apparensite:GST 4050(TAG)First apparent site = 0Announces to computSITE ALFA 0

Plots grid.

Determines altitude: 3

Determines verticalinterval: +5

DOUT 8-3

Announces:REPLOTDEFLECTIONRANGE

8-4



FM 6-40

Table 8-1. Example of replot mission-proximity fuze (M728) (continued)

COMPUTER I

Determines that the-site determined is within+1 mil of previous site computed; it is the true site.Determines true elevation:Final QE (256) - true site (+1) = 255

Determines and announces replot (true) rangecorresponding to elevation 255 = 4130Announces:REPLOTDEFLECTION 3187RANGE 4130

Records replot grid and altitude on record of fire.

HORIZONTALCONTROL

OPERATOR

REPLOT GRID:61173659

Polar plots finalreplot range anddeflection;measures andannounces:REPLOT GRID61163660. Hethen tick marksin black andlabels the finalpin location.

- I h m

VERTICALCONTROL

OPERATOR

Computes second:apparent site:GST +5/4140Second apparent site = +1Announces: SITE ALFA +1

Announces:REPLOTALTITUDE 36 0

8-2. VARIABLE TIME FUZE(M513/M514) REPLOT

When a target is attacked with VT fuzeM513/M514, a height-of-burst correction(20/R initially determined) is added to raisethe trajectory. To replot with the VT fuze, thatheight-of-burst correction must besubtracted from the final quadrant. Thisprovides the final ground quadrant. The siteis subtracted from the final ground quadrantto determine the first apparent elevation. Theprocedures are then the same as those usedfor the PD fuze.

EXAMPLE:

STEPCOMPUTER

1 Determines final ground QE:Final QE (374) - 20/R (x4) = 370

2 Determines first apparentelevation:

Ground QE (370) - site fired(-11) = 381

3 Supervises FDC team insuccessive approximationprocedures

STEP

10

8-5



FM 6-40

Figure 8-4. Time replot.

8-3. MECHANICAL TIMEFUZE REPLOT

a. When a target is attacked with amechanical time fuze, the height of burst isadjusted by the observer to 20 meters abovethe target. The final fuze setting provides anaccurate representation of the target locationand the altitude of a point 20 meters above thetarget (fig 8-4). Consequently, when the timegage line is placed over the final time, therange and 100/R (read under the MHL) andthe elevation and drift correction (read underthe elevation gage line) are true. The replotgrid and altitude can then be determined.

b. The replot procedures are as follows:

(1) Place the time gage line over thefinal time.

(2) Read replot range and 100/R underthe manufacturer's hairline.

(3) Read drift under a line parallel to themanufacturer's hairline passing through theelevation gage line.

c. To determine the true total deflectioncorrection, determine the replot deflection byadding the drift determined in (3) above to theGFT deflection correction. Then subtract thistrue total deflection correction from the finalpiece deflection.

d. Replot grid and altitude are determinedas follows:

(1) The computer determines replotrange and deflection as in b and c above andannounces them to the horizontal controloperator.

(2) The HCO polar plots the target byusing the replot range and deflection anddetermines the replot grid.

(3) The computer subtracts the trueelevation from the final quadrant andobtains true total site.

(4) To obtain true ground site, thecomputer determines the value of 20/R andsubtracts the value from the total site fired.

(5) The VCO determines the VI bymultiplying the true ground site by the replotrange with the M gage point of the GST. Hethen algebraically adds the VI to the batteryaltitude and announces the sum to thecomputer as the target altitude. A completedrecord of fire is in figure 8-5. Table 8-2 is anexample of a replot mission (time fuze).

EXAMPLE:Given: M109A3 (FT 155-AM-2)GFT A: Chg 4, Lot XY, Rg 5140, El 335, Ti18.9GFT Df Corr: R5, Tot Df Corr: L2

8-6



FM 6-40

RECORD OF FIRE

""mnG H5PH3 CALLIFORiRE Tg G T 6. FTRS Am .13. 11G.36 ® / s Tot-rR Y 35-5 G Lb., C2113 & q D F T Lr5 2 -5"

WIDr:Die U/B VA VI t 10Shi - ir + p'u/c 2o/B 5

9 ZREN J E_ "1 i--10 lOmSi NOB orr

FiREORE T 'i /c O Corr 0 Si

INITIAL IRECOMMANDS KFM: M F. S T R ... A S 4 t Rgf93j0 Cht Of 3 196 i..............

. , ,,,, Lot Cho , i : 4 ,E....................

Tgt Locetion Priorityliring SUBSEQUENTIRECOMMANDS unit fMF ee Rg HOD MF Sb FS Ti Chart Df Corr DI Chart NOB Si El G Exp Type

F, Forr C Ft Corr Df (0) Fired tg Corr (tZ)

i: i.........: :16ii~iiii':i:i' .. ~iiii:iiiii:: l700 L440Q/00 t 3 / 9 0 0 1(t5I0 -tn1 fl _22

r-i ___ -so . 3197 0 J# f510+5 -5 -7 284 'U I

X:..T;] : ::X: ::..... .: .: . : :::::.. . . .. ... iiii~ i i i ...... :-....... ......... ............

---iiii 9 7 Z2 2 1-13291 ... 21..T..- -........ I. ...... /97 R60 291 itL

4,.72"'s/= / olt, ... ......... T~~oOk6. 37., . tpo S i

R44IZON/TAL -ERT

EOM P/s7f'ME 1 '5 2JAtwi ao"Z~( %(2I

MLR.001/aoaZR

1S~TE COMUTNEOERPRROPOENTAGESTORAC

.... .. ........ ........ .

Figur 8 ompleed rcord.f.fir. timefuze

Table8-2.ampl of rplot issio-timefuze1 HORIZONTA...VERTICA

I IO N T R O L . C O N T R OSTEP C O M U T E R

J.ERATOR OPERATO

Places the time gage line over the final time anddetermines replot information:

Reads information from MHL:10/R 22Replot Range 4560

Reads information from elevation gage line:True elevation 28 8Drift L6

Determines total replot deflection correction:GFT deflection correction (R5) + drift (L6) = Li

Determines replot deflection:Final piece deflection (3188)- total replotDeflection correction (Li) - 3187

8-7



FM 6-40

Table 8-2. Example of replot mission-time fuze (continued),.

COMPUTER

Announces:REPLOTDEFLECTIONRANGE

31874560

Determines true ground site:Final QE-True elevationTrue total site

-20/RTrue ground site

Announces:SITE ALFA

291288

+3

+4-1

-

4

5

6

7 Records replot grid and altitude on recordof fire.

HORIZONTALCONTROL

OPERATOR

Polar plots dataand announces:REPLOT GRID61153720.

Determinestarget altitude.

VERTICALCONTROL

OPERATOR

True ground site -1X range (GST) x4560VI -4+battery altitude 355Announces:REPLOT ALTITUDE 35 1

Section IICO MPUTER PROCEDUWES

g=4. FADAC REPLOT

FADAC provides a quick means forreplotting targets. It determines the replotlocation by recomputing the ballistictrajectory and displaying the grid andaltitude of the point of impact. The replotprocedures are the same for all fuzes and arefound in the FADAC job aids.

g-5. BATTERY COMPUTERSYSTEM REPLOT

The BCS performs replot functions similarto those for manual procedures. Two operatormethods are used depending on whether theobserver requested the target be recorded ornot. These procedures are explained in theBCS job aids.

8-8

STEP

-1

IL ------ J LA

11 It IL -



T his chapter describes character-istics of and firing data procedures

for various munitions. Manual firingdata solution procedures are also listedwith corresponding examples based onmultiplot GFT settings, SOPs, andknown data from appendix I. Theexamples include special corrections(chap 13). Data in these examples arecomputed for three 2-gun platoons. Thisprovides a means for manual computa-tion for units that must occupy largefrontages without a battery computersystem. Each family of ammunition hasa base projectile that is normally used todetermine registration corrections forthe family. It serves as the foundationfor determining firing data for all othermembers of that ammunition family.Normally, an ammunition family for aparticular weapon system includes allthe projectiles listed on the cover of theTFT for the family's base round. Thecharacteristics of different types ofprojectiles and certain types of missions

require special consideration by the firedirection center.

a. The entry range for computingunit firing data factors from the firingtables or from the ballistic computerswill be chart range. This is determinedto the point at which the observerdesires the ammunition fired. Normally,in manual procedures, it is no tnecessary or practical to determinecomplementary range, because th epossible increased accuracy does notjustify the additional time required forcomputing complementary range.

CALL FOR FIRE BLOCKUSED TO RECORD CALL FOR FIRE. THECOMPUTER CIRCLES OR FILLS IN THEAPPROPRIATE DATA DEPENDING ONWHETHER THE MISSION IS ADJUST FIRE,FIRE FOR EFFECT, IMMEDIATE SUPPRES-SION, OR SUPPRESS.

FIRE ORDER BLOCKUSED BY THE COMPUTER TO RECORD THEFIRE ORDER./ /

Osre146CALL FOR EA ep.9,8 tr AF

Poiw:Ofr oil Uo _ _ _ _ _ _ VA tSmft J a M. 21a A0uqw fVCP

is loss i Ne Cor

INITIALFill COMUANOSU U gCbD. 2Sp mt b Lot Chg f:T I O

UTAC (3T L~Pi)7- in MffA Lxp

COMPUTATION SPACEUSED BY THE COMPUTER TO RECORD ANDDETERMINE PERTINENT DATA.

NOTE: I v GFT SaTT /fi Wq)L\L

MTO BLOCK INITIAL FIRE COMMANDSUSED BY THE COMPUTER TO RECORD THE USED BY THE COMPUTER TO RECORD ANDMESSAGE TO OBSERVER (MTO), ANGLE T, TRANSMIT FIRE COMMANDS. THOSEAND PROBABLE ERROR IN RANGE. TIME SHADED PORTIONS INDICATE WHAT MUSTOF FLIGHT IS RECORDED WHEN SENT TO THE BE SENT TO THE GUNS.OBSERVER, OR IT MAY BE RECORDED INPARENTHESES IF DETERMINED AND NOTSENT TO THE OBSERVER.

Figure 9-1. Record of fire-call for fire and initial computation.

FO

I

RECORD OF Fill

I

9-1



40

SUS]RE(COF

b. Firing data consist of the charge,fuze se t t ing (when app l i cab le ) ,deflection, and quadrant elevation to befired. DA Form 4504 (Record of Fire) (fig9-1 and 9-2) is a multipurpose form thatis organized to allow a smoothflow in

LBSEQUENT CORRECTIONS BLOCKED BY THE RATELO/COMPUTER TOORD OBSERVER'S SUBSEQUENT

tRECTIONS. MAY ALSO BE USED TOORD TARGET LIST.

/

AMMUNITION EXPENDITURE BLOCKUSED BY THE COMPUTER TO KEEP ACUMULATIVE COUNT OF AMMUNITION BYTYPE. CHECK MARKS INDICATE THAT THECOUNT WAS TRANSFERRED TO OTHERRECORDS/CHARTS.

COMPUTATIONSPACEUSED TO RECORD SURVEILLANCE AND FOR

ANYINECESSARY COMPUTATIONS.

ADMINISTRATIVE AND REPLOT DATAUSED TO RECORD ADMINISTRATIVE DATA.DATE-TIME GROUP IS WHEN FIRE FOR.EFFECT WAS FIRED. REPLOT DATA ARERECdRDED AS APPROPRIATE.

FOR SE FTHISFORM, EE M 6-4THEPROPONENTGENCYS TRADO

SUBSEQUENT FIRE COMMANDSUSED TO DETERMINE AND RECORDSUBSEQUENT FIRE COMMANDS. SHADEDAREAS INDICATE DATA THAT MUST BE SENT.PARENTHESES INDICATE DATA WEREDETERMINED BUT NOT SENT, BECAUSE THEDATA DID NOT CHANGE. DEFLECTIONCORRECTIONS AND SITE ARE RECORDED INPARENTHESES AS SHOWN. PLATOONCORRECTIONS FROM THE HASTY CORREC-TIONS TABLES ARE RECORDED IN THISSECTION.

Figure 9-2. Record of fire-subsequent corrections and fire commands.9-2

9-2



FM 6-40

the processing and determination ofdata. It is used for the following:

(1) Recording the call for fire.

(2) Computing firing data for all

types of m issions.(3) Keeping a permanent record of

fire missions.

Note. Major sections are shown withheavy black lines. Shaded portions showitems that must be sent to the cannonsections.

Section IHIGH-EXPLOSIVE MUNITIONS

9-1. CHARACTERISTICSThe HE family of projectiles uses

conventional HE rounds as its base rounds.

These rounds are the 105-mm M1, the155-mm M107, and the 203-mm (8-inch)M106 projectiles. Included in this ballisticfamily are the antipersonnel improvedconventional munitions (APICM) (ICM:105-mm M444, 155-mm M449 series, 203-mmM404), illumination (illum) projectiles(105-mm and 155-mm only), chemical(including white phosphorus, VX, and GB)rounds, and smoke (HC-type) rounds. Theintroduction to the appropriate weapon TFThas a description of the delivery techniquesfor the HE base round.

9-2. COMPUTATIONS FORHIGH-EXPLOSIVEPROJECTILES

a. Description. The HE projectiles arehollow steel cases filled with explosive,normally composition B. They can be fuzedfor air, graze, or subsurface burst.

b. High-Explosive GFTs. The high-explosive GFTs are described in chapter 7.

c. Selection of Charge. Selection ofthe charge to fire is the responsibility of thefire direction officer. He may use the chargeselection table in the introduction of the TFT

to aid in his selection of the optimum chargefor each range. A standard charge can bedesignated manually for the primary zone ofaction.

d. Determination of Firing Data. Inthe manual FDC, the FDO issues a fire orderafter he receives the call for fire and after heconducts his analysis of the target. If noballistic computers or hand-held calculatorsare available, the HCO determines-the chartdata to the target. The VCO in the manualFDC determines the vertical interval between

the battery and the target. He determines andannounces site to the computer, whodetermines the fuze setting (for MT or VTfuzes), deflection, and quadrant elevation tofire. Normally, the manually equipped FDCuses a GFT fan with a GFT setting andgraphical site tables to determine firing data.In the fire-for-effect phase, the VCOdetermines corrections to the battery centerto target center firing data from the hastycorrection tables and announces thesecorrections to the computer.

9-3



FM 6-40

9-3. SAMPLE MISSEONS

a. Adjust Fire, HE/Quich in Effect.Figure 9-3 shows a record of fire for an adjustfire mission with HE/quick in effect.

b. Adjust Fire, HE/VT in Effect.Figure 9-4 shows a record of fire for an adjustfire mission with HE/VT in effect.

Note. In determining corrections for fuzeVT, corrected deflection and quadrant arefirst extracted from the hasty correctiontables. Site is then subtracted from thecorrected quadrant, and the resultingelevation is used to determine the VT fuzesetting.

c. Adjust Fire, HE/Time in Effect.Figure 9-5 shows a record of fire foran adjustfire mission with HE/time in effect.

Notes. 1. In firing fuze time, 20/R must

be added to ground site, and the resultingtotal site must be applied to the elevation.

2. The fuze setting is determined from theinitial time fuze setting.3. The corrected fuze setting is determinedby placing the elevation gage line over thecorrected elevation and reading he correctedfuze setting under the time gage line.

4. If the request for fire for effect includes aheight-of-burst correction, the fuze settingcorrection is applied to the corrected fuzesetting.

LCOL7D OF FILIECALLOO1121 A LT 6 r 3 6$5 Srr RN4Z-iF

Observer. 422 6 jORSis Tgt T rRR 3 5 5 1RFT Lq 2Polor:Dir Ois U _ _VAD 20;:

S :ir L/R +1- U/D .2/R

FlaEOROtRAI;ZOf Corr'i t

INITIAL liECOMMAI4DS t AF g ChtDf 11 El 2SpIsrSb Let Cbg F Ti OfE 2 4

IFOJ 6 j in EU Ammo't£4

tgt LOC iority FiringSUBSEQUENT FIKE OMANDST~ Lctin Unit I____

(eeiAg HOD MIF, b, FlS i Chart Of r, Of Chart og S .i

iF z Dow a Corr C F,F: Conr i Of [W Fired g Corr t2) El QE xp Type

-------- -- t--- - . . . ?...2.'..t.

S9URD AELW E S J 7 M t E CS s9SJ4TESoLrrr ~r LL

::::::::::: :: .i::::::... :.:... :.:.::. :... .. .:. . . ......... ......... . : ...

U, 2 d 2 ~~- --0.........

D.r .. . . OTO iiii :iii :t 8 4 1iii~ Qo;:ot d231 Aepl:tK F::::EPLCE:C2FO2645:T 0 K:I0 ' :: :FOR :USE . S .1 OCT 70 45O THE ROPOLAGEFICTS...T.AD.CFigu9-Lwag adjust fire:..:......E/quic.......... i~i:[ : : ~ ~ : i i i i i ~ ~ ~ ~ ~ i i i i i ~ ~ ~ i i i i i i ~ ~ i:_ii~

.v.-41IT/,6S o+45oy

RKIMcali7 O/ PIACES A FOaM 5W, 1 MAY 6, VOICU $ OIElTt FO iOpoUSEFTH S |cFOUM,|SE oF

Figure 9-3. Low-angle adjust fire HE/quick mission.

9-4



FM 6-40

Observer O FIIS STot BraY *r 3C5 C 07ti1-0"0/1

Pola: Di Di DisU/0VAD v20/3I

sueg PR4=iif Si-+-10 10mnSi NOl1Corr

f i l ODE O f C o r il /

~~~~~::... . . . IS 0 _ i l r iiO I C t

INITIALfillCOMMANDS MFirTng $ g C3.ChiZ

0eA OB MF,SMb, FS li Chart l em iredO Chart N B ~ ~ 1 l p T p

_M Carr Cbg F:z Cei Cprr f C ) 1 p T. . .g.Cor..ar.

Ih Lo C=-rTi,

t I G / . l~ ~ Tlll.... p.Iotrid A.ot i

Figure 9-4. Low-ange adjust fire HE/VT (M728) mission.

Observer FF SSI C C71

r f NCa 5 5 - VB L - yp e

Gri:

lu/rnV

TiDieie ~ y. U / r i g u n i _ $ U _ _ _ U T FE OVAAD/3i3OB T t M Sh, F1 'hurtTf(tIFfeO Li

......... . . . . . .

INIIA F il COMMANDSf MC.tr y :Ij# f : ( Ag 1j9 6 0 II C bs D_| 3 5 3 Q 3 19TyI

MTCTIlO(S AA79150 i 4T (34) P13IF 4 Tiii miff Ammailp

...........

. .......

i~ii, i~i,,,, i:,, .............-_

_ .................... ...............

_ _ _ _ _ t__ '- nit __-______

0___-_____

,b .FI_ l l _ Co 5ft t... Con Of (L2 F~red Ag Cart...........

-- e 9---a

P S I . ~ ~~f~a*.21 -7z4J........... ........ a....

Figure9 5 Lwnge adjst fie.HE/ime.mssion

9-5



FM 6-40

B614P3CALLFCItTPYT 3 75 GFT R4 FnOboorvor B6h423AF@sT POLA K BTRY ALT 355 DFT L7 8 /aGMd: 5vI tao L-Poo 0 3 5 0 - 3 9 8 0 U/0 VA ' I

Stt:________ aU/D20/U0 L4,F ANtr P ._ V0 Uc ..,, o/10

1.I 10M51+10Io0110Corr -*5112100110 T I ,g AMC DfCorr L 3' Si (-tOf)t Z

7Emn Xl.,OA-X:I a ~l~ h.INA la OMADF a C ChtDOf32.00 El 335Spo.tr C -c. .C...ZSbot.CT Fz i .5Z03...0..

I,,, 0 0. .. ... ,..-.L ....

l, GT) . A 7051 1-4 T.'l ....... Pi 1Ammo0

Tg Lootloo Prioity Fii::a SU0SIOUEC lCOMANDS__ ___- Uoft .. ,__ _ SU____t_' I_ O / A I

D, oI Dov 1100 FSb .... C . DfCorr Of CE c.1100 SinXfb, F oz Cor Ch,Ft Corr Of ( i Pod Ug Cowrr_. , _ _ -.... 3203 2 _,_ 4t3433 3, -.. ....... ..... X.X

..... . B 3203 Rb - o 373 2"i W'~i+5320O30i+- 3150" - S 343 Wa T0-i

. ........... --------------............................ ' " : Iiii' ii'iiiiii- - - - . . . . . - . . . . . . . . . . - - - - - - -

.............. .,

.................... 2,2 ::::'+' ' :~~~~~::ii ~~~l

-- , . .R .V. . . .T. . . . . . .L .P.c . . . . . .X.,

, : . : . . :+ . . . .. ...... . ... .. . .. ....

. . . . . . . . . . . .

"PLyT 7I)SP TO THIE SOUTH I PT CPT L'Lt.ST CAS/17 PRC -- I+- 0 -, 5

MVC C) 0) 0.-..- o -- IS

............ ' .. .......... ...... 0 I o

rca 450 QEPLACISAt Oat) 4504, 1 ItIAT 6 , L1lC11 S OUSOLETE FOQi SEOF 11lS O~). SEU 6-40;

Figure 9-6. Low-angle fire-for-effect HE/time mission.

d. Fi re For Effect, HE/Time. Figure9-6 shows a record of fire for a fire-for-effectHE/time mission.

Note. 20/R is computed and recorded inthe HOB Corr block as shown.

9-49 APCM PIROJECTILESThe APICM projectiles are available for the

105-mm, 155-mm, and 203-mm howitzers.The projectile cases are ballistically similarto the HE cases. Therefore, the firing data for

these ICMs can be based on HE firing data.The APICM round is a base-ejectionprojectile containing grenades that areexpelled at a predetermined height of burst(table 9-1).

Table 9-1. Antipersonnel improved conventionalmunitions.

NUMBER OF

CALIBER PROJECTILE GRENADES

105 mm M444 f 18155 mm M449series 60

203 mm M404 104

9-6



a. GFT Firing Data Computation.

(1) GFT APICM scales. Graphicalfiring tables for the base HE projectiles haveAPICM scales. There are ballistic differencesbetween the 155-mm M449 and the M449/E1APICM projectiles. Therefore, different GF Tscales are required for each of these types ofrounds. Their firing data cannot be in-terchanged. HOW 155 mm 155AM2HEM107scales have both the M449 and theM449A1/E1 scales printed on the face of thegraphical firing table. All other 155-mmseries GFTs have only the M449 scales. For155-mm systems not using the HOW 155 mm155AM2HEM107 data, the TFT solutionmust be used to determine firing data forM449A1/E1 projectiles (para c below).

(2) GFT 1CM scale. An ICM scalehas two parts. One part is for quadrantelevation, labeled QE, and the other part isfor fuze setting, labeled FS (fig 9-7). The scaleis constructed to compensate for ballisticdifferences between the base HE projectileand the APICM.

b. TFT Computation. Tabular firingtable addendums are published for APICMprojectiles to supplement the base HE tabularfifing tables. An addendum is divided intosections. Each section contains ballisticcorrection data for a given propelling charge.Figure 9-8 shows an example section. Eachsection contains tables as described below:

(1) Table A. Table A containscorrections to convert the HE quadrantelevation to the APICM quadrant elevation.It contains range to impact for anonfunctioning APICM round and correctionfactors for height-of-burst and rangechanges.

(2) Table B. Table B containscorrections to convert the M564/M582 fuzesetting (HE data) to the APICM fuze setting.It also lists antipersonnel fuze settingcorrections for height-of-burst and rangechanges.

(3) Ta b l e C. Table C containscorrections to convert the M520A1 fuzesetting (HE data) to the APJCM fuze setting.O(4) Tables D, E, and F. These tables

S a r e designed for unit self-defense firing ofantipersonnel improved conventionalmunitions.

Figure 9-7. M449 scale.

FT 155 ADD-I-1

PROJ. HE, M449 MODSFUZE, MT. M565

TABLE A

QUADRANT ELEVATION

CHARGE4G

II il PIL 78CORRECTIONS TO CORR

QUADRANT CORRECTIONS TO QUAD ELEV FOR LOWELEVATION QUADRANT ELEVATION FOR AN INC OF LEVEL RANGE

FOR FOR PROJECTILE, 50 M 100 M WINO OF TOPROJ, M107 M449AI1 M449 M449E1 IN HGT IN RG 1 KNOT IMPACT

NILS ItS .1LS MILS MILS MILS METERS METERS

325 42 38 39 11.2 7.1 3.7 5833

330 41 37 39 11.1 7.2 3.6 5883335 41 36 35 11.0 7.3 3.6 5933340 40 36 37 10.9 7.5 3.6 5982345 40 35 37 10.8 7.6 3.5 6032

350 39 34 36 10.7 7.7 3.5 6080

355360365370

375

380385390395

39383838

34333232

36353534

10.710.610.610.5

r $ + 4 +37 31 33 10.5

7.981O8.18.3

8.4F I 7 1 1 1

37373636

31303029

33333232

10.410.410.310.3

400 36 29 31 10.3 9.1

405410415420

36353535

2828-2727

31303030

10.310.210.210.2

8.58.78.89.0

9.39.49.69.8

3.53.43.43.4

3-.3

3.33.33.23.2

3.2

3.13.13.13.1

6129617862266273

6321

636864146461650?

6552

6597664266866730

CHARGE46G

1

N564FUZE SETTlING

FORPROJ, M107

9.6-10.610.7-14.214.3-17.8

2

M449AI

-1.3

17.9-20.8 -1.0

20.9-23.32 3 . 4 - 2 5 . 4

25.5-27.127.2-28.5

26.6-29.7

-0.9-0.8

-0.?-0.6

-0.5

TABLE S

FUZE SETTING

3 4

ORRECTIONS TOFUZE SETTINGOR PROJECTILE,

M449 449E1

-1.2 -1.3-1.1 -1.2-1.1 -1.2

-1.1 -.1.1

-1.1 -1.1

-1.1 -1.1

-1.1 -li O-1.1 -1.0

-1.1 -1.0F U. I ________ I

FT 155 ADO

PROJo HE, M449 MOOFUZE, MT,

5 6

CORRECTIONS TO FSFOR AN INCREASE OF

50 METERS 100 METEIN HEIGHT IN RANG

0.40.0 0.40.1 0.4

0.1 0.5

0.1 0.50.1 0.60.1 0.60.2 0.7

0.2 0.7

29.8-30.8 -0.4 -1.1 -1.0 0.2 0.830.9-31.6 -0.3 -1.1" -0.9 0.2 0.931o7-32.4 -0.2 I1.1 -0.9 1 0.3 0.932.5-33.0 -0.1 -1.1 - 0 . 9 j 0.3 1.0

t,= 1.... .. • '33. L-3.

33.6-34.034.1-34.434.5-34.834.9-35.1

35. 2-35.4

35.5-35.635.7-35.835.9-36.036.1-36.2

0.0

0.10.20.30.4

0.5

S -1.1

S -1.1-1.1-1.1-I°1

-1.1

-0.9

-0.8-0.8-0.8-0.8

-0.?

0.3

0.40.40.50.50°6"

1 1 7 4-0.40.70.80.9

Figure 9-8. Example of tabular firing table section.t

-1.1-1.1-1.1-1.1

-0.7-0.7-0.7-0.7

0.60.70.70.8

1.1

1.21.31.51.6

1.8

2.0

9-7 FO

HOW155 mm1S5AM2HEMI07

CHARGE 5GB

zooo

t . . .... - ...vI

i i





FM 6-40

d. Subsequent Fi r ing D a t a Computa-tion. Height-of-burst corrections cannotbe made by use of the GFT for antipersonnelimproved conventional munit ions.Therefore, the APICM tabular firing table

addendum must be used to compute all HOBcorrections. The correction values in tables Aand B, column 5, for an increase of 50 metersin height of burst are applied as positivevalues. To compute corrections for a decreasein height of burst, change the sign of thecorrection factor to a negative value.Compute subsequent firing data for APICMby using the graphical firing table and thetabular firing table.

(1) Determine HE firing data for thesubsequent correction.

(2) Determine APICM data asdescribed in steps c(2) and c(4) above. If anHOB correction is given, go to steps (3) and(4) below.

(3) Correct the ICM fuze setting byusing table B of the appropriate ICM tabularfiring table addendum.

(a) Enter column 1 with theM564/M582 HE fuze setting.

(b) From column 5, extract thecorrection for a 50-meter increase in height ofburst.

(c) Multiply the factor by the numberof 50-meter increments needed.

(d) Apply the HOB correction to theICM fuze setting that was determined fromthe ICM fuze setting scale on the GFTcorresponding to the HE data for thesubsequent correction.

iff 1

Note. The ICM piece deflection is the HEpiece deflection determined for thesubsequent correction.

(4) Determine the APICM quadrantelevation to fire by using table A of theappropriate ICM tabular firing tableaddendum.

(a) Enter column 1 with the HEquadrant elevation to the nearest listedvalue.

(b) From column 5, determine thecorrection factor for a 50-meter increase inthe height of burst.

(c) Multiply the correction factor bythe number of 50-meter increments needed.Express the answer to the nearest mil.

(d) Apply the HOB correction to theAPICM quadrant elevation corresponding to

the subsequent correction.

Note. Low-level wind corrections are notused when computing datafor antipersonnelimproved conventional munitions.

9-5. SMOKE PROJECTILESa. Types.

(1) Hydrochloroethane. Hydrochlo-roethane (HC) smoke projectiles are availablefor 105-mm and 155-mm howitzers. They areused for screening, spotting, and signalingpurposes. The projectile has no casualty-producing effects. This base-ejectionprojectile is ballistically similar to the HEprojectile. It is fitted with a mechanical timefuze M565 or M577. The round expels smokecanisters that emit smoke for 40 to 90 seconds(sec).

(2) Burster-type white phosphorus.White phosphorus projectiles are availablefor 105-mm and 155-mm howitzers. They areburster-type projectiles that can be fired withPD or MT fuzes. The WP projectile has anincendiary effect and is ballistically similarto the HE projectile. Normally, shell WP isemployed for this incendiary effect. Theprojectile can be used also for screening,spotting, and signaling purposes.

(3) Enhanced smoke-producingwhite phosphorus . The M825 WPprojectile is an enhanced smoke-producingDPICM round. Employment of the M825projectile is discussed in paragraph 9-19.

b. Employment . Smoke is employedby use of quick smoke and immediatetechniques.

(1) Quick smoke.

(a) A quick smoke mission is fired tobuild a deliberate smoke screen. The FDCprocesses the quick smoke mission as shown

9-9

if



FM 6-40

in figure 9-10. One, two, or three platoonsmay fire in effect to screen an area of up to 600meters. For planning purposes, obscurationtime could be maintained from 4 to 15minutes. The following is a list of quicksmoke mission characteristics:

Delivery technique: Quick smoke(small-area suppression).

o Type of target: Small area of 100 to 600meters.

o Number of guns: One, two, or threeplatoons. (Responsiveness dictatesthat quick smoke missions be fired byplatoon.)

o Type of ammunition: HC or WP.

o Sheaf: Parallel.o Obscuration time: 4 to 15 minutes.

o Command and control: Approval ofmaneuver battalion commander.

(b) Upon receipt of the call for firerequesting quick smoke, the FDO takes thefollowing actions:

0o Uses table 9-2 to determine the number

of platoons required to fire the mission.He enters the table with caliber, winddirection, and width of target to be ob-scured and determines the number of

platoons to fire as two.o Determines the rate of fire and total

number of rounds to fire per tube. Heenters the appropriate quick smoketable (table 9-3, 9-4, 9-5, or 9-6) withweather conditions (including windspeed determined from the met messageor observation), and duration of smokescreen requested by the observer.Weather conditions are explained intable 9-7.

o Issues his fire order.

EXAMPLE:Weather conditions are observed asfavorable with 10-knot winds. The totalnumber of rounds to fire per tube is five, witha rate of fire of one round per minute (min).

3CALL FO FI [r 3-7 3 GFT R /A.FS

Observer 3 TF/S/1 R 16 mT)F _ - t L 7 a10 aoo, 6'. 265LPolar:Dir Dis U/D ,VA -.

Sbift Dfr L/a U/D 20/0SCREaM mREELJNE 500 CfRoSwniM 7 -457IE Si 10 lom Si HOD orr

FlatODER A -. c "Df Corei L - +1I11TIAL IRECOMMANDS M MFIPJGHTECW4 d 2I g5/30 ______

7g Ti;+, IDp etir Sb Lot Chg. Fe.i....GMOG ,T9PSA , A C 7 6 4 iEFS SM

7? 6L-sST n F z i1n"Eff Ammo spyyTg ~inPr io r i ty+ iring

T$t Locotion - iSUBSEQUENT FIRE OMMANDS

D MF IDe fig HOD MF. S,FS

Chort Of Corr Of Chort HOB Siz-. 9 Corr Cfg, F . Corr D ( Fired lIg Corr ( El E lip Type....... .............: i i'~ :~~iii' +'::,:l ..... i i~i iiiiii'i',i?- )i ( i] ............. (2, .-: o 'i',iii',iiii:i,14 ... ii ii < ........... .....::::::::::::::::::::::, , .,:. ... , ,,

... tQ.......... '......

-, - -,w U S ;a9 3 J,:, + i~'' ?.......... ......... ... ...............................................

.. ......... ....- -----~:::E:ii:::: i:iiii:- :ii: :::i:::::l

.... t.D..G.S./.. ..................

Figur.....e Quc smoke ison e p...le..F ig re 91 . ....................... e

9-10



FM

Controls the firing of the rounds in ac- (d) The HCO determines an dcordance with the rate of fire extracted announces chart range and deflection. Thefrom the quick smoke tables once the VCO determines and announces site.unit is in fire-for-effect phase. (e) The computer determines and

announces the fire commands for the HEadjustment.

(c) The computer determines and (f) The observer sends his subsequentannounces initial fire commands. corrections.

Table 9-2. Quick smoke planning data.

WIDTH OF TARGET TO BE OBSCURED (METERS)WEAPON/ WIND DIRECTIONAMMUNITION CROSS HEAD/TAIL

HC 400 500 600 100 200 300155 mm

WP 200 300 400 100 200 300

HC 300 400 500 100 200 300105 mm -

WP 100 200 300 100 200 300

Platoons to fire 1 2 3 1 2 3

Table 9-3. Quick smoke data-155 mm, shell smoke, fire for effect.

DURATION REQUESTED BYFORWARD OBSERVER (MINUTES)

WEATHER WIND SPEED RATE OF1 1 1 1CONDITION (KNOTS) FIRE 4 5 6 7 8 9 0 11 2 14 15

ROUNDS PER TUBE

IDEAL 5 1RD/2 MIN 223313414 51 5 6677FAVORABLE 5 1 RD/2MIN 22 3-3-4 4 5 5 6 6 7 7

10 1 RD/1 MIN 2 3 4 5 6 7 8 9 1 0 h 11 2 h 315 1 RD/40SEC 3 4 6 7 9 012 31516..[8b9

MARGINAL 5 1 RD/40 SEC 3 4 6 7 9 1012 3T5168

Table 9-4. Quick smoke data-1 55 mm, shell WP, fire for effect.

DURATION REQUESTED BYFORWARD OBSERVER (MINUTES)

WEATHER WIND SPEED RATE OF1 1 1 1CONDITION (KNOTS) FIRE 2 3 4 5 1 1112131415

ROUNDS PER TUBE-IDEAL 5 1 RD/2 MIN 23 3 4 1 4 514 61617178 819

FAVORABLE 5 1 RD/1MIN 4 5 6 7 1 1210 1RD/3SEC 4 6 8101214161802 24 2630

_ __15 1 RD/20 SEC 6 9 12151821 27 0 33 3639 2 5MARGINAL 5 EXCEEDSRATE

I I OF FIREL

Table 9-5. Quick smoke data-105 mm, shell smoke, fire for effect.

DURATION REQUESTED BFORWARD OBSERVER (MINUT

WEATHER WIND SPEED RATE OF-T TI TCONDITIONS (KNOTS) FIRE 3 ± 5 11

" _ROUNDS PER TUBE

IDEAL 5 . 1RD/1MIN 213 4 5167 18 11(d1112131

FAVORABLE 5 1RD/iMIN f43 4 5 678 91dl1112131410 1 0RD/3EC 7 91 3 51 91212

MM _(31_15 1 RD/24 SEC 4 6 9 11 64 9 2124P629MARGINAL- 5 1 RD/20 SEC 4 7 0 3 6 1922 25 28t 137$0

Table 9-6. Quick smoke data-105 mm, shell WP, fire for effect.

DURATION REQUESTED BFORWARD OBSERVER (MINUT

WEATHER WIND SPEED RATE OFCONDITIONS (KNOTS) FIRE 3 5 6 7 8 91011 213141

ROUNDS PER TUBEIDEAL 5 1 RD/40SEC 5 E141113141611 2212FAVORABLE 5 1 RD/31SEC 6 8 1 1 3

10 1RD/11SEC 1 1 2 7 1 3 3 9 51 515 1iRD/10SEC 1622 28344 628 4 76

MARGINAL 5 EXCEEDS RATE OF IR "

Table 9-7. General atmospheric conditions and the effects on smoke.

SMOKE CONDITION TIME OF DAY EXPECTED SMOKE BEHAVIOR A(TEMPERATURE WEATHER CONDITIONS THE SMOKE DRIFTS DOWNWIND.

GRADIENT) WIND DIRECTION

IDEAL 1. Night-until 1 hour after sunrise.(Inversion) 2. Wind speed less than 5 knots.. Sky cover less than 30 percent.ALL THREE CONDITIONS MUST BE MET. Stable condition-ideal for smok

employment.

FAVORABLE This condition occurs most often 1-2 .hours before and after sunrise and ,when the wind speed is 5 knots or more vand/or the sky cover is 30 percent or Neutral condition-favorable formore. smoke employment.

MARGINAL 1. Day- beginning 2 hours after sunrise.(Lapse) 2. Wind speed less than 5 knots. Vk."t $3. Sky cover less than 30 percent. Unstable cor'*:tion-marginal forALLTHREE CONDITIONS MUST BE MET. smoke employment.

FOLDIN-11



FM 6-40

INoteIn the exa-mple shell HE did notrequire adjustment. O

(g) The computer a n n o u n c e ssubsequent fire commands to the adjustingpiece. He then determines shell smoke fuzesetting by reading the M564 fuze settingunder the time gage line and subtracting 2.0seconds.

(h) The observer spots the round andsends the correction.

(i) The FDO supplements his fireorder by saying BY ROUND AT MYCOMMAND, SPECIAL CORRECTIONS

BY PLATOON.Wi) The computer announces the

subsequent fire commands: RIGHT AND

Figure 9-11. Example of an immediate smoke mission.

9-12

CENTER 5 ROUNDS, BY ROUND ATMY COMMAND, SPECIAL CORREC-TIONS. (See chapter 13 for computation ofspecial corrections.)

(2) Immediate smoke.

(a) An immediate smoke mission maybe fired as a separate mission or as a followupto immediate suppression. The FDCprocesses the immediate smoke mission asshown in figure 9-11. Immediate smokemissions normally are fired by a two-gunplatoon. One gun fires shell WP, fuze quick,and the other gun fires shell HC smoke, fuzetime, on the first volley. If additional volleysare fired, both guns will fire shell HC smoke,

fuze time. When firing the M825 smoke round,both guns will fire the M825 projectile for theinitial and any subsequent volleys. Unit SOPshould detail the number of volleys and

OLDOUT 9-11



FM 6-40

dictate which gun will fire the WP and whichwill fire smoke, if applicable, for thesemissions. The following is a list of immediatesmoke mission characteristics:

o Delivery technique: Immediate smoke(point suppression). The immediatesmoke technique can be used in animmediate suppression mission on atarget of opportunity by unit SOP. Amix of WP and HC normally will followthe initial suppression rounds whenimmediate smoke is requested.

o Type of target: Point or small area of150 meters or less.

o Number of guns: One platoon (twoguns). Responsiveness dictates thatimmediate smoke missions be fired by

platoon.o Type of ammunition: First rounds, WP

or HC; second rounds, HC; or all rounds,M825 smoke.

o Sheaf: Platoon center to target center.

o Obscuration time: Thirty seconds to fiveminutes.

o Command and control: By SOP and/orapproval of maneuver companycommander.

Note. Because speed is of the utmostimportance in an immediate type mission,the hasty correction tables, while valid, maybe time consuming. Therefore, th eimmediate smoke procedures call for use ofthe alternate special correction method ofdetermining chart data from a plottedplatoon location on the firing chart. Thismethod negates the need for any platooncorrections.

(b) Upon receipt of the call for fire, the

FDO determines and issues the fire order.(c) The computer sends initial fire

commands.(d) The HCO determines and

announces chart range and deflection fromthe platoon location on the firing chart. TheVCO determines and announces average site.

(e)- The computer sets the announcedrange under the MHL for the appropriatecharge on the GET. He determines the shell

HC fuze setting by reading the M564 fuzesetting under the time gage line andsubtracting 2.0 seconds. He does notdetermine a fuze setting for the WP round,because it is fired with a PD fuze.

(f) The computer determinesdeflection to fire for both rounds by addingthe total deflection correction to theannounced chart deflection.

(g) The computer determinesquadrant elevation for both rounds byreading elevation under the appropriate gageline and applies the announced average site.He ignores any corrections for projectileweight differences.

(h) Fire commands are continued inthe normal manner.

(i) In anticipation of subsequentcorrections, the HCO/VCO places the gridover the initial target location and orients thetarget grid in the appropriate direction. Afterreceiving the correction, he plots thecorrection and announces new chart data.The computer then computes data andannounces fire commands as describedabove.

(3) Computer procedures fo rimmediate smoke. Data are computed foran immediate smoke mission by determiningshell HE/fuze Q data. The same deflectionand quadrant are fired for both WP andsmoke. The time settings for the smokerounds are determined by subtracting 2.0from the displayed time of flight.

9-6. ILLUMINATINGPROJECTILES

a. Illuminating projectiles are availablefor the 105-mm and the 155-mm howitzers.They are used for illuminating a designatedarea for observing enemy night operations,for adjusting artillery fires at night, formarking locations, or in G/VLLD missions.

b. I l l umina t ing pro jec t i l es arebase-ejection projectiles fired with MT fuzes.The filler consists of an illuminating canisterand a parachute assembly. The two models ofilluminating projectiles for the 105-mmhowitzer are the M314A2 and the newerM314A3 that has a slightly longer burningtime. The 155-mm system also has two

9-13



~RFM-40

illuminating models. These models are theM118 and the newer M485A2 that has asignificant increase in illumination time.

C. Illumination is conducted by use of thefollowing techniques:

(1) The one-gun illumination pattern isused when effective illumination can beaccomplished by firing one round at a time.

(2) The two-gun illumination pattern isused when an area requires moreillumination than can be furnished by onegun.

(a) The two-gun illumination rangespread pattern is used when the area to beilluminated has greater depth than width(fired parallel to the line of fire).

(b) The two-gun illumination lateralspread pattern is used when the area to beilluminated has greater width than depth(fired perpendicular to the line of fire).

(3) The four-gun illumination patternis used to illuminate a large area. Four roundsare fired-simultaneously by using both thelateral and the range spread patterns.

9-7. ELLUMINATINGPROJECTILE MANUALPROCEDURES

There are two manual methods that may be

used for computing data for the illuminatinground. One method uses a specialilluminating projectile GFT, and the othermethod uses part 2 of the base HE tabular-firing table.

a. I l l umina t ing GFT. Graphicalfiring tables have been developed for use withall 155-mm M485 illuminating projectilesand with the 105-mm M314 and M314A2E1projectiles. Figure 9-12 shows anilluminating graphical firing table. Thescales on the illuminating GFT, from top tobottom, are as follows:

(1) 100/R scale. The 100/R scaledenotes the number of mils necessary to shiftthe burst 100 meters laterally for a givenrange. 100/R is read to the nearest 1 mil.

(2) Range scale. The range scale isthe base scale on the graphical firing table.All other scales are plotted with reference.toit. Range is read to the 'nearest 10 meters.

Figure 9-12. Illuminating graphical firing table.

9-14



FM 6-40

(3) Elevation-to-impact scale. Theelevation-to-impact scale is graduated inmils. Low-angle elevation increases from leftto right and is read to the nearest 1 mil.High-angle elevation increases from right toleft and is printed in red. The elevation-to-impact scale is used to determine the range(on the range scale) to which a nonfunction-ing projectile will travel.

(4) Height-of-burst scale. Theheight-of-burst scale is labeled at the left andright of the main body of each set of scales.These scales are graduated in 50-meterincrements. They extend from 350 meters to850 meters.

(5) Quadrant elevation scale. TheQE scale indicated for each listed height ofburst gives the quadrant elevation to achievethe height of burst and the desired range. TheQE scale is graduated in mils and is visuallyinterpolated to the nearest 1 mil.

(6) Fuze setting scale. The FS scaleconsists of a red line for each whole fuzesetting increment for the MT fuze. The valueof each line is printed in red at the bottom ofthe scale. The fuze setting is read for thedesired range and height of burst to anaccuracy of 0.1 fuze setting increment byvisual interpolation.

b. Charge Selection. The FDO selectsthe charge to fire. He should select the lowestpractical charge to prevent a malfunctioncaused by the parachute ripping when theflare is ejected from the projectile.

c. One-Gun Illumination Mission. Anexample of a one-gun illumination mission isshown in figure 9-13. The manual FDCprocesses the mission by use of the GFT in thefollowing manner:

(1) Upon receipt of the observer's callfor fire, the FDO analyzes the target andissues his fire order. The RATELO composesand transmits the message to observer.

(2) The computer determines and sendsinitial fire commands to the firing battery.

(3) The HCO plots the target andannounces chart data to the computer.

(4) The VCO determines and, an-nounces the vertical interval between thebattery and the target area to be illuminated.The computer lists the information on therecord of, fire. The vertical interval isexpressed to the nearest 50 meters.

(5) The computer records the chartdeflection on the record of fire as thedeflection to fire. No deflection correction isapplied.

Figure 9-13. Example, of a one-gun illumination mission.

9-15



FM 6-40

(6) The computer determines andrecords the fuze setting and quadrantelevation to fire. He places the MHL over theannounced chart range and determines thedata from the appropriate height-of-burstscale.

(7) The computer completes andannounces the fire commands.

(8) When direction is announced by theforward observer, the chart operators preparefor subsequent corrections by orienting thetarget grid in the normal manner.

d. Illumination Range Spread FiringData. When the observer requests a rangespread, the platoon closest to the batterycenter should fire the mission. A value of 500meters (400 meters for 105-mm weapons) isadded to chart range, and fuze setting andquadrant are determined for one gun. A valueof 500 meters is then subtracted front thechart range to determine fuze setting andquadrant for the other gun. Both guns firechart deflection (fig 9-14).

e. I l l umina t ion L a t e r a l Spr e adFir ing Data. If weapons in the battery arespread far enough apart laterally, firing databased on chart data from battery center can

be used without modification to achieve alateral spread. The optimum spread for155-mm illuminating rounds is 1,000 meters.The optimum spread for 105-mm illumi-nating rounds is 800 meters. If modificationto deflection is necessary, 100/R may beapplied to achieve the desired spread (fig9-15).

f. Range and Lateral Spread FiringData. To produce a range and lateralspread, a combination of the aboveprocedures may be used to determine firingdata for four guns (fig 9-16).

(1) When the vertical interval is 0meters, the 155-mm M485 illuminating roundhas a 600-meter optimum height of burst. Allother illuminating rounds have a 750-meteroptimum height of burst. The computermodifies the optimum height of burst byadding the value of the vertical interval,expressed to the nearest 50 meters. The resultis the appropriate height-of-burst scalevalue.

(2) Using the 600-meter height-of-burst scale on the GFT and the announcedchart range of 4,030 meters, the computerdetermines the fuze setting (12.8) and thequadrant elevation (438) to fire.

Figure 9-14. Record of fire-range spread illumination mission.

S

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Observer FFE/IS/$5Tgt S T-.T 3 5 ISs

Grid: 1--1b SI--- +Polar:Oir Dis UID VA C.

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9-16

S



FM 6-40

CALLOR IRE rcr6 37.5 ... oO /Observe-AF/-/I s/ g ... r Y 35 + ) 1Wft ..

Polor~le Dki U/D ,.. _ VA v0O'. k., Ul uI20/ft

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Fill ORDER oflCorr l o e l L 0 5 S iINITIALFIRECOMMANDS FM MFt.;:M it4I4.. hiDE 246$ nSp nstr ft5tf4COS S L.Lo t LYChu"* F T 0'./* a S.*,1 oSI", l4, lM,"

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,,, . _ ...., ' .... :::i ,,, ..........-_...,....

Figure 915. Record of fire-lateral spread illumination mission.

............ ..,.,'...., .. x ,,x.,.. .A. ......,,. ' .. € +. .........

,,,,.,., ,,.,o....,,, ~.l.............. , ,,,... v ,.,o , ;s ,......,.......,..--...

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Polar:D irD.../0...... .. 4..................................... ds -r 20/R,

Oir /It /D Mr SAVAPAfa

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9-17

Figure 9-1 6. Record of fire-range and lateral spread illumination mission.



FM 6-40

Section IIDUAL-PUIRPOSE DRPMOV/ED-OR9EV WA7ORAL ML 9IIDTDOOII

Table 9-8. DPICM/FASCAM projectiles.

IDPOCpv

WEAPON PROJECTILE NUMBER OF SUBMUNITIONS

155 mm M483A1 88 (64 M42s, 24 M46s)

203 mm M509E1 195 M42s

FASCA

ADAM

WEAPON PROJECTILE NUMBER OF MINES

155 mm M692/M731 36

AL

WEAPON, PROJECTILE NUMBER OF MINES

155 mm M718/M741 9

9-8. CHARACTERESTECSDual-purpose improved-conventional

munitions and the family of scatterable'mines (FASCAM) are base-ejection,payload-carrying rounds. They are fired withMT fuzes (M577. or M724) and are filled with anumber of submunitions. During flight, thebase of the projectile is blown off, and thesubmunitions are scattered about the targetarea. Table 9-8 shows the number and type ofsubmunitions in the DPICM/FASCAM

rounds. The M825 enhanced smoke round isanother DPICM projectile.

9-9. DPI[CM PROJECTI[LES

The DPICM projectiles contain two types ofdual-purpose grenades. Both types arecapable of penetrating more than 2.5 inchesof rolled homogeneous armor. They are also

capable of fragmentation for incapacitatingpersonnel. The M577 MT fuze is preset tofunction over the target area and initiate theexpulsion charge. The expulsion chargepushes the grenades out of the container andonto the target area. The projectile can bemodified for the self-registration mode. The.self-registration mode causes the round topoint detonate so as to be visible to theobserver and destroy the submunitions. Italso may produce an airburst for conductinghigh-burst registrations.

9-10. DPCI4 COMPUTATIONSBY USE OF THE GIFTAND TIFT

Dual-purpose improved conventionalmunitions procedures for using of the GFTand TFT are as follows:

9-18



FM 6-40

a. Upon receipt of a call for fire, the FDOanalyzes the target and announces his fireorder. Figure 9-17 shows a record of fire for aDPICM mission.

Note.. The GFT setting in effect is GFT A:Chg 4, Lot IY, Rg 6080, El 460, Ti 25.5; GFTDf Corr: R2, Tot Df Corr: L9. A GFT setting

_for the M483A1 projectile can be determinedby firing any method of registration(precision, high burst, abbreviated) or byderiving a GFT setting by use of the met + VEtechnique. The met + VE technique, using FT155-AN-I, is the preferred method because ofthe high cost of firing a DPICM registration.

RECORD OF FIRE

cURFa ... TGT Z.4 (,FT R2-o£63515H ' A l 13$ %TRY cj5 IWT L 5 ,3,, a

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INITIA FiRE OMMANDS #F,,MF..R...:Chi ofCI 3 1 / z.... .. . ...... ....

Sp mtr P CAL CORRECTiONSAt ' .Lot.Iy, a,, , Ti u. (y Xi.- -2------- .7........Tot t " "P r i unkitSUBSIvNT FIRE COMMANDS

bk, MF Dcv Kg NOR MF,SII, FS Ti Chrt DfCorr Of Cher NOR Si El U Ep TpSFt, . Corr O R F i t C orr of () Fired Re Cerr ()

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Figure.917. Rcroi

) iue9-7 e o r ffre-PC msin

9-19



FM 6-40

b. The RATELO announces the messageto observer.

c. The HCO determines and announceschart data.

d. The computer announces initial firecommands; places the MHL over theannounced range; and determines andrecords elevation, drift, and the M577 fuzesetting from the appropriate gage line on thebase scale. The elevation and fuze settingdetermined are for 0 meters height of burst(graze-burst data).

e. The computer then determines thegraze-burst quadrant by algebraicallyadding the announced site to elevation.

f. The computer now applies ballistic

corrections to graze-burst data. Ballisticcorrections can be applied by use of FT155-ADD-J-1 or the graphical firing table.

(1) Tabular firing table addendummethod. The computer enters the J-1addendum with the appropriate charge andextracts the ballistic corrections to apply toquadrant. He enters column 1 of table A withthe nearest listed value to the graze-burstquadrant determined in paragraph d above.He extracts the ballistic correction fromcolumn 2 and algebraically adds the ballisticcorrection to the graze-burst quadrantelevation. He then enters table B to determinethe ballistic correction to the fuze setting. Heenters column 1 with the graze-burst timedetermined in paragraph d above. Heextracts the correction to the fuze settingfrom column 2 and algebraically adds thecorrection to the self-registering time.

(2) Graphical firing table method.The computer determines dual-purpose timeby placing the MHL over the M577graze-burst time, determined in paragraph dabove, on the M577 graze-burst time scale.

Without moving the MHL, read up to the fuzescale labeled ICM M483A1, and read thedual-purpose fuze setting from themanufacturer's hairline.

Note. Minor differences (±0.2 fuze settingincrement) between TFT and OFT data areacceptable.

g. The computer now determines thedual-purpose quadrant by placing the MHL

over the graze-burst quadrant, determined inparagraph e above, on the graze-burstelevation scale. Without moving the MHL,read up to the elevation scale labeled ICMM483A1, and read the dual-purposequadrant from the manufacturer's hairline.

Note . The dual-purpose ICM andFASCAM quadran t scales on th e155ANIM483A1 are mislabeled EL ratherthan QE.

h. The computer determines thedeflection to fire.

i. Next, the computer may apply platoon

special corrections (procedures are shown inchapter 13), and he announces firing data toeach platoon.

j. When all gun sections announceREADY, the FDO gives the command to fire.

k. If the observer sends the subsequentcorrection that includes a height-of-burstcorrection, the HCO orients the target grid,plots the deviation and range correction, andannounces chart data.

1. The computer determines graze-burstdata as described in paragraph d above.

m. To derive dual-purpose data, thecomputer then applies ballistic corrections tothe graze-burst data. Ballistic correctionsmay be applied by use of the TFT addendumor the graphical firing table.

n. To compensate for the 100-meterheight-of-burst correction, the computer nowdetermines ballistic corrections. Thesecorrections must be found in the TFTaddendum, because the GFT does not listheight-of-burst corrections. Corrections aredetermined for both quadrant and fuzesetting.

o. The computer determines quadrantcorrections by entering table A with thegraze-burs t quadrant , determined inparagraph e above, and extracting th ecorrection factor from column 3. The valueextracted from column 3 is for a 50-meterincrease in height of burst. In this example,the correction required by the observer calls

9-20



FM 6-40

for a 100-meter increase in height of burst.Therefore, the value in column 3 must bemultiplied by 2. The resulting value will thenbe algebraically added to the dual-purposequadrant determined in paragraph m above.

p. The computer determines fuzecorrections by entering table B with thegraze-burst fuze setting, determined inparagraph e above, and extracting thecorrection factor from column 3. The valueextracted from column 3 is for a 50-meterincrease in height of burst. The correctionrequired by the observer was for a 100-meterincrease in height of burst. Therefore, thevalue in column 3 must be multiplied by 2.The resulting value will be algebraicallyadded to the dual-purpose time determined inparagraph m above.

q. The fire-for-effect data represent acenter-of-battery to center-of-targetsolution. Special corrections for each platoonmay be applied on the basis of the proceduresin chapter 13.

r. The corrected FFE data are announced.

s. When all sections report READY, theFDO commands FIRE.

t. The observer sends END OFMISSION, PLATOON DISPLACING,

ESTIMATE 25 CASUALTIES, OVER.u. END OF MISSION is reported to the

gun sections.

9-11. COMPUTERPROCEDURES FORDHICM

See the appropriate job aids for computer

procedures for dual-purpose improvedconventional munitions.

9-12. FASCAMPROQJTECTIWLES

a. The purpose of FASCAM projectiles isto delay, disrupt, destroy, and disorganizeenemy forces by emplacing the artillery-delivered minefield.

b. The two types of FASCAM projectilesare area denial artillery munitions (ADAM)and remote antiarmor mine system(RAAMS).

(1) ADAM. The ADAM projectile is

used to deny the enemy the use of certainterrain areas. Each mine arms itself after itcomes to rest on the ground. Individual tripwires are extended from each mine. The tripwire activates the explosive when disturbedby movement. The minefield willself-destruct after a preset period of time. Thepreset time is determined by the modelnumber of the round.

(2) RAAMS. The RAAMS projectileis effective against armored vehicles. Themines become armed within a few seconds

after landing. Any metallic object passingnear the mines will cause them to activateand damage or destroy the object. Some of themines have an antidisturbance firingmechanism. It will activate the mine ifdisturbed by minefield clearance operations.If, after a certain period of time (shortself-destruct [SD] for less than 24 hours; longSD for more than 24 hours), the mines havenot been activated, they are destroyed by aself-contained destruction mechanism.

c. Normally, 155-mm field artillery units

carry short SD ADAM/RAAMS as part oftheir basic load. Long SD ADAM/RAAMSare used primarily for planned minefields insupport of barrier/obstacle plans. Such useallows for advance logistical coordination tostockpile long SD ADAM/RAAMSprojectiles.

d. The field artillery has three roles in theuse of scatterable mines.

(1) It is a delivery system for plannedminefields to support the barrier/obstacle

plan.(2) It may use scatterable mines to

establish a minefield in front of or on top oftargets of opportunity.

(3) It may deliver scatterable mines as aharassing agent in conjunction with othermunitions, such as DPICM, HE, and smoke,during the attack of any target. Use ofFA-delivered mines in any capacity requiresdetailed coordination among the G3/53, the

9-21



FM 6-40

engineer officer, and the fire supportcoordinator.

9-13. FASCAM9 EMPLOYMENT

Upon receipt of a planned FA-deliveredminefield mission, the FDC determines dataon the basis of registration correctionsdetermined from the M483A1 (DPICM)registration. Then, ballistic corrections areapplied for either shell M718/M741 (RAAMS)or shell M692/M731 (ADAM). Normally, theemplacement of a tactical minefield is afire-for-effect mission. When verification of alocation is needed, a forward observer mayadjust a tactical minefield.

9-14. FASCAMCOMPUTATEfONS

The following are procedures to emplace aplanned minefield by use of the GFT andTFT. Upon receipt of DA Form 5032-R (FieldArtillery Delivered Minefield PlanningSheet) (fig 9-18), the FDO inspects sections A,B, and C.

a. Section A has been completed by thefire support coordinator at the requestingunit. It identifies basic information about themission necessary for issuing a fire order andcomputing data for a mission.

b. Section B has been completed by theG3/S3/engineer. It includes remarks relativeto the mission.

c. Section C has been completed by thefire support element (FSE)/FSO. It includesremarks relative to the mission.

d. Section D will be completed by the

FDO. It will help him emplace the minefield.(1) For planned minefields, the target

number is the same as that in section A, block1. Unplanned minefields are given a targetnumber by the field artillery firing unit. If thetarget is preplanned, the FDO fills in sectionD, block 22, with the target number fromsection A, block I (fig 9-18).

(2) The unit emplacing the minefield isentered in section D, block 23 (fig 9-18).

(3) The HCO plots the minefield endpoints, determines the minefield center, anddetermines the range and deflection from thebattery to the minefield center. The rangefrom the firing unit to the minefield center isentered in section D, block 24 (fig 9-18).Range is necessary when computing thesafety zone and when determining thenumber of aimpoints needed to emplace theminefields.

(4) Use of high- or low-angle fire toemplace the minefield is indicated by an X inthe appropriate box (section D, block 25)corresponding to mines emplaced(ADAM/RAAMS). The angle of fire isnecessary for computing the safety zone andthe number of aimpoints necessary toemplace the minefield. The ADAM/RAAMSminefield is based on a 400- by 400-meterplanning module except when RAAMS isdelivered by low-angle fire. In that case, a200- by 200-meter module is used. Therefore,the FDO considers this when determining thedelivery technique to provide the minefielddepth required (fig 9-18). Referring toinformation in section A, block 5, and cross-referencing that information with the size ofthe minefield planning modules, the FDOdetermines the type of trajectory he will firein the mission.

(5) The delivery technique used is'indicated in the appropriate locationin block26 (fig 9-18). Determination of the deliverytechnique is necessary for computing thesafety zone and for selecting the number ofaimpoints necessary to emplace theminefield. The FDO selects the deliverytechnique on the basis of the location of thetarget. Transfer is used if the minefield iswithin the current GFT ransfer limits. If the.minefield is outside the current GFT transferlimits, the met + VE delivery method is used.

(6) Aimpoints are placed in section D,block 27 (fig 9-18). If there is just oneaimpoint, the coordinates are entered in theFROM space and NA is entered in the TOspace. The determination of individualaimpoints is discussed in paragraph 9-15.

(7) Section D;-block 28;:is used for thedate-time group, of the mission. This is thetime that emplacement of the minefield iscompleted (time of impact of last mines fired).

9-22



FM 6-40

FIELD ARTILLERY DELIVERED MINEFIELD PLANNING SHEETFor u e o ihs form Se -C 6 20 5 The prooonen aqency is TRADOC

SECTION A MINEFIELD DATA

1 TARGET NUMBER 2 PRIORITY 3 REQUESTER

4 MINEFIELD END POINTS (COORDINATES)

F R O R MLONG-_13___I____ ____24_4DM

5 MINEFIELD DEPTH 6 MINFFI[LD WIDTH

7 ADAM tAPERSi DENSITV 8 RAAMS tA1)P E NSITY

9 SELF DESTRUCT TIME 10 SCHE DUL ED MINFE11LD

11 CAUTION NLT EMPLACEMENT TIME 12 APPROVAL AUTHORITY 13 DATI TIME (NkOUP (DTGi

14 REMARKS

SECTION B-G3/S3/ENGR

15 DTG RECEIlVED i16 {TG SAF TY j(.)NF ISSI MINAT[ D

1 REMARKS

SECTIO)N C FSE 'FSO

18 DTG TO UNIT D 19 DIG FROM UNIT I20 DT(; 70(3 . S3 f N(;R

21 REMARKS

SECTION D FDC DATA

22 TARGET NUMBFR 23 lINING UNII 24 RANGI t() MINEIELD (INTFR

A -A-t425 TRAJECTORY 276 DILIVERY TI 'HNI()LJI

ADAM. HIGH LOW RAAMSj HI(GH j) I ()A MI ) •VI IANSI ( )51 Nye 4 145 [Ii27 AIMPOINT COORDlNATf)S tFTI AND RIGHT OR SINGLE,

28 DTG MISSION C"OMPLETE)

29 REMARKS.

I)A Form 50132-R, ,Jan 82

Figure 9-18. Field artillery delivered minefield planning sheet.

9-23





FM 6-40

angle. For example, the FDO enters thematrix with met + VE, M692/731 ADAMlow/high angle, and a BMA greater than 800mils and extracts table 4.

c. Enter table 4 with the range to the

minefield center (expressed to the nearest2,000 meters [if exactly halfway between,express to lower range]) and the desired widthof the minefield. Extract from the table thenumber of aimpoints required to emplace theminefield.

Table 9-11. Mine employment table 2.

Delivery Technique: Transfer or met + VEShell: M718/741 (RAAMS)Trajectory: Low angleBMA: Greater than 800 mils

DESIRED MINEFIELD WIDTH (METERS)

100 200 300 400 500 600 700 800 900 1,00041246

4,000.1 2 2 3 3 4 4 5 5 6

6,000 1 2 2 3 3 4 4 5 5 68 00 0.. 1 2 2 3 3 4 4 5 15 6

RANGE 10,000 2 2 ,3 4 .7 5 6(METERS) 12,000 2 3 -3 4 4 5 5 6 -7F- -

141000 2 3 3 4 4 5 5 6 6 7

16,000 3 3 4 4 5 5 6 7 717,500 3 3 4 4 H, 5 6 6 7 7


Delivery Technique: Transfer or met + VEShell: M692/731 (ADAM)

M718/741 (RAAMS)Trajectory: Low angle or high angle (ADAM)

High angle (RAAMS)BMA: Equal to or less than 800 mils


100 200 300 400 500 600 700 800 900 1,000

4,000 1 2 2 2 2 3 3 3 3 46,000 1 2 2 2 2 3 3 3 3 4

8,000 1 2 2 2 2 3 3 3 3 4RANGE 10,000 2 2 2 2 3 3 3 3 4 4

(METERS) 12,000 2 2 2 3 3 3 3 4 . 4 414,000 2 2 3 3 3 3 -4 4 4 416,000 2 2 3 3 3 3 4 4 4 4

17,500 2 3 3 3 3 4. 4 4 4 5

9-25



FM 6-40


Delivery Technique: Transfer or met + VEShell: M692/731 (ADAM)

M718/741 (RAAMS)Trajectory: Low angle or high

angle (ADAM)High angle (RAAMS)BMA: Greater than 800 mils


RANGE(METERS)

100 200 300 400 500 600 700

4,000 1 1 1 2 2 2. 26,000 1 1 1 2 2 2 28,000 1 1 1 2 2 2 2

10,000 1 1 2 2 2 2 312,000 1 2 2 2 2 314,000 1 2 2 2 2 3 316,000 2 2 2 2 3 3 317,500 2 2 2 2 3 3 3

800 900 1,000

3 3 33 3 33 3 33 3 .33 3 43 3 43 4 43 4 4

- a I I I vI I I


Delivery Technique: Observer adjustShell: M718/741 (RAAMS)Trajectory: Low angleBMA: Equal to or less than 800 mils


100 200 300 400 500 600 700 800 900 1,000

4,000 2 2 3 3 4 4 5 5 6 66,000 2 2 3 3 4 4 5 5 6 68,000 2 4 4 5 5 6 6 r7

10,000 2 3 3 4 4 5 5 6 6 712,000 2 3 3 4 4 5 5 .6 6 714,000 2 3 3 4 4 5 5 6 6 716,000 3 3 4 4 .5 5 6 6 7 717,500 3 3 4 4 5 5 6 6 7 7

RANGE(METERS)

9-26



FM 6-40


Delivery Technique: Observer adjustShell: M718/741 (RAAMS)

Trajectory: Low angle

BMA: Equal to or less than 800 mils


100. 200 300 400 500 600 700 800 900 1,00

RANGE 4,000 1 2 2 3 3 4 4 5 5 6(METERS) 17,500


Delivery Technique: Observer adjustShell: M692/731 (ADAM)

M718/741 (RAAMS)Trajectory: Low angle or high angle (ADAM)

High angle (RAAMS)BMA: Equal to or less than 800 mils


100 200 "300 400 500 600 700 800 900 1,00

RANGE 4,000 1 1 1 2 2 2 2 3 3 3(METERS). 1.7,500


Delivery Technique: Observer adjustShell: M692/731 (ADAM)

M718/741 (RAAMS) .... .Trajectory: Low angle or high. angle (ADAM)

*High angle (RAAMS)BMA: Greater than 800 mils

DESIRED MINEFIELD WIDTH (METERS)100 200 300 400 500 600 700 800 900 1,00

4,000 1 1 2 '2 2 2 3 3 3 36,000 1 1 2 2 2 2 3 3 3 3

, * 8,000 1 "' 2 2 2 3-" 3 3 3 4RANGE 10,000 1 2 2 2 2' 3 3 3 3 4

(METERS) 12,000 1 2 2 2 2 3 3 3 3 414,000 1 2 2 2 2 3 3 3 3 L4

.1,00 2 2 2 2 3 3 3 3 4 4S17,500 2 2 2 2 3 3 3 3 4 4

9-27



FM 6-40

9-16. LOCATION OFAIMPOINTS

a. Module Size 400 x 400 Meters, EvenNumber of Aimpoints. Place aimpoints200 meters left and right of the center pointalong the centerline. Place the others atintervals of 400 meters (fig 9-19).

b. Module Size 400 x 400 Meters, OddNumber of Aimpoints. Place the firstaimpoint at the center point of the minefield.Place the others at intervals of 400 meters leftand right of the center point along thecenterline (fig 9-20).

c. Module Size 200 x200 Meters, EvenNumber of Aimpoints . Place theaimpoints 100 meters left and right of thecenter point along the centerline. Place theothers at intervals of 200 meters.

d. Module Size 200 x 200 Meters, OddNumber of Aimpoints. Place the firstaimpoint at the center point of the minefield.Place the others at intervals of 200 meters leftand right of the center point along thecenterline.

9-17. NUMBER OFPROJECTILES PERAIMPOINT

The number of projectiles required toachieve the desired density within, eachmodule (as defined by each aimpoint) isdetermined by entering table 9-18. Entryarguments are the projectile

type, trajectory,and desired density.

Figure 9-19. Module size 400 x 400 meters, even number of aimpoints.

Figure 9-20. Module size 400 x 400 meters, odd number of aimpoints.

Table 9-18. M718/M741 RAAMS and M731 ADAM rounds per aimpoint.

HIGH ANGLE RAAMSDesired density 0.001 0.002 0.004Rounds per aimpoint 24 48 96

LOW ANGLE RAAMSDesired density 0.001 0.002 0.004Rounds per aimpoint 6 12 24

LOW ANGLE/HIGH ANGLE ADAMDesired density 0.0005 0.001 0.002Rounds per aimpoint 3 6 12

9-28



FM 6-40

EXAMPLEOn the basis of the minefield densityinformation from section A, block 7, of thefield artillery delivered minefield planningsheet, the FDO determines that six rounds

should be fired at each aimpoint.

9-18. MANUAL DATADETERMINATION

a. The FDO can now issue the fire order.See figures 9-21 and 9-22 for an exampleADAM mission. The GFT setting in effect isGFT A: Chg 4, Lot IY, Rg 5340, E1378, Ti 21.9;GFT Df Corr: L2, Tot Df Corr: L9.

b. After the fire order has been issued,mission processing can begin. The computer

issues initial fire commands.

c. The HCO determines and announceschart data to the minefield center, and theVCO determines site.

d. The computer, with the datadetermined in paragraph c above, recordsdrift and determines a graze-burst quadrant.This quadrant is used as an entry quadrant toenter FT 155-ADD-L-1 to extract correctionfactors for low-level wind corrections.

Note. Low-level winds will cause ADAMmines to be blown away from the intendedaimpoint. Consequently, a modification, indmeters, to the location of the aimpoint mustbe made. so that the mines land at theintended location.

RECORD OF FIRE

CALLFilFRE rFTFIObserver AF/FFEIISIS TIt 13,TR 555 7)F L too01

Gri:A M P o 'T: G 3/3 OQ--0-TPoler:Dir Dis U/C VA LShift Dir U/ID ) N L 2011

SC)W9.-T ? E S T B C][C4 1 9Si -+10 Om i NOB orr

flIllORDER a_aFFEISPEC 9\E A'P2A rs A\ W LT cI DDCoryr5 - 9INITIAL IRECOMMANDS FM ,M F t :, 2. .6 Rg ChtDf II 4 ,.

, ... .. . ..:::.......... .. '..,.. . .SP ns?; DpJL. 5hAT).,m cLot -BY Chg FiT' Ti Of

MTO 14 T Pit iF in FEU Ammo 1op

Igt Location FPriorityir SUBSEQUENTIRECOMMANDS6 0' Unit U UI i O M

Dir, MF Des I ig NOB MF, Sh, FS Ti Chart Df Corr Of Chort NO@ Si 01Type-,t Cor Chg, Fz Corr Df ) Fired Rg Corr ( I

- W7717777777777771_ ;..2 +0 jib 4 S4 sq/a t5... 9 4

..........--- -- -- --... ...... _... :1 6 :10 4:+:::::

__ Z3 __ .273 ~ _

,,,-,,, a,,,_,--,-,_ _ _ _

._ , + i:iiii~i, i::ii i :iiii~ii~i~:: :+ ,,........................17 """"1............................................ i ~i~~i........"..... T

-------- --w- ----------.-

D s r M S R - N O D E Q E To ) iTAL AIM PT. ./T.5 L A , A $ ) L-. w I M s .

I ty A IG / - / Tgt. ....... . Ac 7 'e.po, Grid Roo At....

AFORM450 RPLACES CA FORM 504, 1 MAT 76 WHICH IS OBSOLETE FORUSEOFTHISFORM, EE M6-40;DAlOCT 78 45 4'THE PROPONENTGENCYS IADOC

Figure 9-21. Record of fire-ADAM mission.

9-29





FM 6-40

GUN1Ti (25.1) + (-0.1) = 25.0Df (2856) + (R7) = 2849QE (443).+ (+2) = 445

GUN 2Ti (25.1)'+ (-1.5) =23.6Df.(2856) + (L17) = 2873QE (443)-+ (-28) = 415

j. The computer now applies the ballisticcorrection to the graze-burst data that havebeen modified by the special corrections. Theballistic corrections can be applied by usingthe GFT or FT 155-ADD-L-1.

1 (1) Ballistic corrections detevmined byuse of the TFT for gun 1 are as follows:

(a) The computer enters FT155-ADD-L-1, table A, column 1, with thegraze-burst quadrant determined inparagraph i above(for gun 1)and extracts theballistic correction from column 2.

(b) The computer algebraically addsthe ballistic correction to the graze-burstquadrant.

(c) The computer enters FT155-ADD-L-1, table B, column 1, with thegraze-burst fuze setting determined inparagraph i above (for gun 1)and extracts thecorrection factor from column 2.

(d) The computer algebraically addsthe correction to the graze-burst time.

(2) Ballistic corrections determined byuse of the GFT for gun 2 are as follows:

(a) The computer places the MHLover the M577 graze-burst time (for gun 2)determined in paragraph i above on the M577self-registering scale. Without moving theMHL, the computer reads up to the time scalelabeled ICM 692/731, and reads time under

the manufacturer's hairline.(b) The computer now determines the

dual-purpose quadrant by placing the MHLover the graze-burst quadrant on the graze-burst elevation scale for gun 2 determined inparagraph (a) above. Without moving theMHL, read up to the EL scale labeled IC M692/731, and read the quadrant under themanufacturer's hairline.

It. The computer may now complete hisfire commands.

1. The FDO now computes section D,block 27 of the field artillery deliveredminefield planning sheet and forwards it tothe fire support officer.

m. Procedures for emplacing a planned

RAAMS minefield are identical to those foremplacing ADAM, except that low-levelwind corrections are not applied.

9-19. M825 PROJECTILEThe M825 projectile is a field artillery

delivered 155-mm base-ejection projectiledesigned to produce a smoke screen on theground of 5 to 10 minutes duration. Thesmoke screen is produced when the payload isejected from the projectile by a predeterminedfuze action. After ejection, the WP-saturatedfelt wedges in the payload fall to the groundin an elliptical pattern. Each wedge thenbecomes a point source for smoke. The M825is designed to be ballistically similar to theM483A1 family of projectiles. It consists oftwo major components-the projectile carrierand the payload. The projectile carrierdelivers the payload, which consists of 116WP-saturated felt wedges, to the target.

9-20. M825 COMPUTATIONBY USE OF THE GFTAND TFT

Procedures for use of the M825 smokeprojectile by use of the GFT and TFT are asfollows: (See figure 9-23 for associated recordof fire.)

Note. The GFT setting in effect is GFT A:Chg 4, LotIY, Rg 5340, El 378, Ti 22.0; Tot DfCorr: L9, GFT Df Corr: L2.

a. The FDO analyzes the target andissues a partial fire order.

Note. The HE adjustment is conductedwith DPICM in the self-registering mode.

b. The computer issues the initial firecommands.

c. The HCO determines and announceschart data, and the VCO determines site.

9-31



FM 6-40

Utry OTO&2 f89 go '~9T.. Rapist ridRpitAt

Figure 9-23. Record of fire-smoke M825.

Table 9-19. Relative humidity.

SCREEN RELATIVE HUMIDITYREQUIREMENT (PERCENT) TABLE

80 9-20INFRARED 50 9-21

20 9-2280 9-23.

VISIBLE 50 9-24

20 9-25

d. The computer places the MHL over theannounced range and records drift andelevation.

e. The computer determines andannounces deflection to fire.

f. The computer determines andannounces the self-registering quadrant tofire.

g. While initial fire commands are beingcompleted, the FDO determines theammendments to his fire order.

(1) The FDO enters table 9-19 with therelative humidity furnished by the metstation and infrared (ir) screen requirementdetermined from the fire order or the call forfire. He extracts the table he will use todevelop his amendment.

9-32

CALLOR IRE f194TeV2 9 6FF Z F sbserver 40- F/I$S PL' Z goTt..,7 Dt F" 0/

Grid:

P lar:Dir..Din.U/D.VA20/

'N .4 Si+10los Si MODCorr

PHiREOROPSh/4 3ft4 S(Fr C g6'ThTC 2Dt Corr L ' -INITIALIRE OMMANDS -M tPfg 2 Cht Cl 3) A

........Sp ntr Chg' F ? Tif

sh.Dp-g totto 11LFT.9EAITE4 l P.s~ Ss UthP 4JJGT .%2 ) Q j(BTFn Eff AmmoExpn.

Tgt Locution SUBSEQUENTIDECOMMANDS

mf oDv 1119 OD MF. Sht. PS Ti Char? Df Corr Df Chars NOB Si §1 lop JVpeIV ,itI or CoFz Corr of (LQI fired fig Carr 42)

i"....1 ..

_. . . . . . .. ... . . . . .- . --- -- __ _. - . . . ._ . . .

... .. .. . : . . .

; :.... .. .. i i -... .i-...i.-... '_--_-43----

X...-. ..CIL



Table 9-20. M825-near infrared, 80 percent relative humidity.

I 1_______J WIDTH OF TARGET (METERS) RATE OF FIRE

WIND WIND DIRECTION EMINUTES BETEATMOSPHERIC VELOCITY'BETWEEN II 1 ROUNDS ROUNDSCONDITIONS (KNOTS) CROSS HEAD/TAIL h1 WEAPON) 1 PLATOON)

IDIFZ IILIZ Ioo300 1,100 1,600 1,700 90 200 400 650J1 5 ][ 65 400 900 1,300 1,400 90 200 400 600 35.5

FAVORABLE 10 200 600 1,600 1,900 80 200 390 550 12.5

15 100 400 1.600 2,000 70 180 370 550 1 1.5MARGINAL 5 11100 150 450 500 40 150 340 4401 1 1.5

PLATOON TO FIRE 1/2 1 23 1/2 1 2 3 __

Table 9-21. M825-near infrared, 50 percent relative humidity.

_ _ _ ___ WIDTH OF TARGET (METERS) I RATE OF FIRE

WIND WIND DIRECTION MINUTES BETEATMOSPHERIC VELOCITY OBETWEEN R N

. ... .. SN T S R O U N D S R U DCONDITIONS (KNOTS) CROSS HEAD/TAIL (1 WEAPON) (1 PLATOON)

IDEAL 5 I500 1,000 1,300 1,400 90 200 400 600 3.5 5.5

5 200 600 1,100 1,200 80 200 400 600 2.5 4

FAVORABLE 10 80 300 1,000 1,300 60 180 350 550 11.5

15 60 200 700 1,300 50 160 330 500 .5MARGINAL 5 60 150 350 450 30 100 300 350 1 1.5

PLATOON TO FIRE I1/2 1 2 3 1/2 1 2 3 J ____

Table 9-22. M825-near infrared, 20 percent relativehumidity.

WIDTH OF TARGET (METERS) RATEOFFIREMINUTES MINUTEs

WIND WIND DIRECTION B E T EATMOSPHERIC VELOCITY...BETWEENCONDITIONS (KNOTS)I 1 ROUNDS ROUNDSCODIIL K )CROSSHEAD/TAIL(1WEAPON) (1PLATOON)__,___, __. J [350 800 1,300 ,00 ]LI3II 3ii0 2I 5

5 150 500 1,000 1,100 70 200 400 550 23.5

FAVORABLE 10 50 250 700 1,100 50 160 330 SOO0101

1 30 150 500 800 40 140 300 450 .5 .5M A G I A 5 1[4 _100 300 40011 30 100 250 300 [{ 1

9-9-33



Table 9-23. M825-visible infrared, 80 percent relative humidity.

WIN WIND DIRECTION MINUTES MINUTES

ATMOSPHERIC VELOCITBETWEENCONDITIONS (KNOT ) CROSSHEAD/TAIL 1WEAPON) ON

IDEAL J511900 1,400 1,200 1,900 -100 200 440 660 6.5 8

5 700 1,100 1,500 1,600 100 200 440 650 56.5

FAVORABLE 10 400 1,100 2,000 2,200 90 200 410 600 2

15 200 900 2,200 2,400 80 200 400 550 1.5

MARGINAL 5 7{ 140 250 500 600 50 150 350 460 1.5 j 2

PLATOON TO FIRE K1/2 1 2 3 1/2 1 2 3


______ WIDTH OF TARGET (METERS) [ RATE OF FIRE

WINDI W INDDIRECTIONMINUTES MINUTESC IN K ROUNDS ROUNDS

CONDITIONS (KNOT ) CROSS HEAD/TAIL (1 WEAPON) (1 PLATOON)

IDEAL 5 800 1,200 1,700 1,8 100 200___430__640__5.5_

5 500 900 1,400 1,500 100 200 430 620 3.5

FAVORABLE 10 200 700 1,400 1,900 90 200 400 580 1.5 2.5

15 100 500 1,400 2,000 80 200 380 540 11.5(MARGINAL J[ 5 1.5__________________________________)II~iII

PLATOON TO FIRE 1/2 1 2 3 1/2 1 2 3


_______ _ WIDTH OF TARGET (METERS) RATE OF FIRE

WIND WIND DIRECTION MINUTES MINUTESATMOSPHERIC VELOCITY OUBETWEEN R U NCONDITIONS (KNOTS? CROSS HEAD/TAIL (1 WEAPON) (1 PLATOON)

IDEAL 5 650 1,100 1,500 160[ 90 200 420 630 5131111115 300 800 1,300 1,400 90 200 400 600 3 5.5

FAVORABLE 10 100 450 1,300 1,700 70 190 380 56012

jI 5 50 300 1,300 1,700 60 190 360 530 11.5MARGINAL 5I 1 O10 10 400 sooJl 40 140 330 400 { 1.5 1.5

PAONTFIE1/2 1 2 3 1/2 1 2 3LX IZ

DOUT 9-33 9-34

40

DOUT 9-33 9-34



FM 6-40

EXAMPLE:Entering table 9-19 with a relative humidityof 20 percent and no infrared requirement,the FDO extracts table 9-25.

(2) The FDO enters table 9-25 with theatmospheric conditions and wind speed(determined from the current ballistic metmessage or personal observation) and targetwidth and wind direction (as reported in thecall for fire).

(3) To determine the number of roundsper gun to fire, the FDO divides the number ofminutes smoke is required by the number ofminutes between rounds.

(4) The FDO announces the amend-ment to his fire order.

h. The observer sends the subsequentcorrection and requests smoke.

(1) The HCO determines and an -nounces chart data.

(2) The computer places the MHL overthe announced chart range and determinesgraze-burst data.

(3) The computer enters FT 155-ADD-Q-1 with the appropriate charge and extractscorrections for the smoke round.

(a) Table A contains corrections tograze-burst quadrant and deflection. Thecomputer enters column 1 with aself-registering quadrant. From column 2, heextracts the corrections and applies them tothe graze-burst quadrant. From column 8, heextracts the corrections and applies them tothe graze-burst deflection.

(b) Table B contains corrections tograze-burst time. The computer enters

column 1 with the graze-burst time andextracts the corrections and applies them tothe fuze setting.

(4) The computer announces firing datafor shell smoke.

(5) The round is fired and the observersends FIRE FOR EFFECT.

(6) The computer then computes specialcorrections for each platoon (chap 13).

SECTION III

ROCKET-ASSISTED MUNITIONS

9-2 1. CHARACTERISTICSa. Rocket-assisted projectiles (RAP) are

available for the 105-mm, 155-mm, and203-mm howitzers. They are designed toextend the range of the howitzers. The basicrocket-assisted projectiles are filled withhigh-explosive material. They produce blastand fragmentation in the target area. The203-mm system also has a rocket-assistednuclear projectile (M753) that is ballisticallysimilar to its base HE rocket-assistedprojectile. Computation procedures for thethree basic HE RAP are identical. Theballistic computers and the hand-heldcalculator can be used to determine firingdata for these projectiles. Consult theappropriate job aids for specific instructions.Manual procedures are discussed below. The

105-mm and 155-mm projectiles are firedonly in the rocket-on mode. The 203-mmprojectile may be fired in either the rocket-onor rocket-off mode.

b. The 105-mm rocket-assisted projectileis the M548. The 155-mm projectiles are theM549 and M549A1. For the M109A2/A3weapons, these projectiles are fired withcharges 7 (M4A2) and 8 (M119A1). The M198howitzers may use charges 7 (M4A2), 8(M119AI), 7R (M119A2), and 8S (M203 onlyfor the M549A1 projectile). The 203-mm HErocket-assisted projectile is the M650. It is thebase projectile for the 203-mm M753 rocket-assisted atomic projectile. Rocket-assistedprojectiles should always be fired by use ofcurrent GFT settings, because most RAPmissions are expected to be fire-for-effect

9-35



FM 6-40

missions. The multiplot GFT setting isrecommended. When no RAP registrationdata are available, a multiplot GFT settingshould be developed by use of muzzle velocitydata, current powder temperature, and rocket

motor temperature (assumed to be the sameas the powder temperature).

9-22o MANUALCOMPUTATIONS

Manual procedures for computing HE RAPfiring data are identical to those forconventional HE rounds. The rocket-assistedprojectile GFTs and GSTs are similar to andread the same as those for conventional HErounds with two exceptions. The 155-mmM549A1 GFT has no fuze setting scale, and

the 203-mm M650 GFT has supplementalscales for the M753 nuclear projectile. Thefollowing is an example of a manual firemission for the 155-mm RAP M549A1 (fig9-24 and 9-25):

a. Upon receipt of the observer's call forfire, the FDO analyzes the target and issuesthe fire order. The RATELO composes andtransmits the message to observer.

b. The computer determines and sendsinitial fire commands.

c. The HCO determines and announceschart data.

d. The VCO determines and announcessite.

e. The computer determines, announces,and records firing data. If a GFT setting isavailable for the rocket-assisted projectile,firing data (drift, elevation, and time offlight) are determined by use of theappropriate gage lines. If no GFT setting isavailable, the computer will determinedeflection, range, and fuze (203-mm only)corrections to GFT data by use of the TFT andmet correction techniques (chap 10).

(1) Determine corrected chart data.Compute met data corrections on DA Form

4200 (Met Data Correction Sheet), andmanually apply the corrections to the chartrange and deflection.

(2) Use the GFT to determine drift,elevation, and time of flight corresponding tothe corrected chart data. If no GFTs areavailable, use the TFT, and interpolateelevation and fuze setting (203-mm only)from table F.

(3) Complete, announce, and record theremainder of the fire commands.

T6B2CALL fOFIDI -FTT 58+o,.,,oT6 B3 A@ESS oBTR{ .516

Pobr:Oir Dis U/D ..... _ VA ,, ,

Sbift DirV I .- U1/O-RD'VE H IC LE T . +o,

Anos/n 4D/a

20/0

WOD onf

... ... . .. .3.IS...

uo P (0 TGT A C 7816 14...'.............in " I .. '"1 o.lipg# t o otion Priority Fic:o IUOSEOUI FIN COMM ANDS

W-it ._. . .... . .. .

.01r, MF Dowv 120 moo0 , FS Chrt1f orrl hatimo o lp Tp•b ,x Corr Ch, F € rr Of ( ) II~od Q9O Corr (Si)

: ..... .. .T T , o _._ i~ii i ,............... ..... . ... .. ......I.

. .. . . . . . . . , . . . . . . . . . _..-_. . ... . . . .

I D O T G /.z21/r4/' 1ITot AC 7 216 1 Qoclt.ni

9-36

Figure 9-24. Example of a met data correction sheet-rocket-assisted projectile.

Dtry I O~otAh



tIET DATA CORRECTION SHEETFor uao of Ohio orm, coo FM 6-40; propononl ogoncy io TRADOC.

QATTURY DATA tIIT SSAGIZ

APGEZNAIRQ LAGATITUDIE TYPE"MESSAGE OCTAN:T AREA/U1IT

0 AT0 |TIME -ALT t P q a s s u a l

AL TOP OTRY 0Go, ,(1")

LANE N94Ci t fP DIR VIDAMPPEEDCA Y 9TE AtlQDENSITYALT 07 OP 0OPLfl7LL..I

DIR? A O LAM6&)PbCORRECTIOMN

ALT OP TARGET %%nOI tCORRECTIED VALUEVI1i ~HE GHT OP OURS?

ACOVE TAROCZT

ALT OP DURST

- (htroolootALT OP O "or I1HEIGHT OP TARGEIT 1 cou~ G CMART RG IENTRY G

WINDOMPONENTS AND DEFLECTION

CHEN DICTION OP WIDMPISmLIZS THAN DI PFIACE ADD

DIRECTION OP DAMP

CHART CA EcTIONaiAIAIoSMRRP

CROSS 1IDMPOTS G CROSS VDINDLCARD SPEEDIo O L 52m UNAT-CORN Conn

CAMPG~ P EEC 0 C O RR09FL

RANGE DAMP TAILcX/l KNOTS CORATDEL1

t2T RANGE CORRECTION

K1110D STANDARD VARIATIONS PRtOM UNIT PLUS tiANUs

VALUZS VALUES STANDARD CORRECTIONSRANGE CAUAD M%0 H367_

AIR T=AP too%0

PROJDElIIGHT ____A i r O 1ROTATION __- __

tvva_2 --, 1@I .. MATRANGECORNRevil.

COMPUTATIONOF YE

2occi rd oii01WMgAt TOTAL RANGIEVE CORRECTION

PROP J~l CHANGE O MV E R N GTEMP FJ P FOR PROP TEN ...I it -I' RACTION

LL - I¢ -EAM/S

]

NV NIT - M.(VcANGEC O R A S I I C I N 4 L I . O RRECTION

TOTAL RANGECORN ACTION g

2 - AVG VA

Figure 9-25. Example of a record of fire-rocket-assisted projectile.

9-37

FM 6-40

CAt

F--- - i . - - -I- - I - - I I I M L

1 4-, 9 twoV

i"

I



FM 6-40

9-23. REGISTRATION ANDDETERMIENATION OFTHE GIFT SETTING

In a combat environment, the unit mayconduct registrations (chap_ 12), especiallyhigh-burst, with the rocket-assisted roundfor at least one weapon for a selected fire unit.For 105-mm and 155-mm howitzers, the GFTsetting will provide increased accuracy infiring the rocket-assisted projectile. TheM650 203-mm registrations will yield GFT

settings for the nuclear M753 K-transfertechnique and for other conventional (RAP)203-mm fire missions. An inferred GFTsetting may also be computed if noregistrat ion is fired. A met solved

concurrently with the GFT settingdetermination will establish positioncorrections for the met + VE technique.Position constants are determined by thesolution of a concurrent met by use of thetabular firing tables (chap 10). If therocket-on mode is used, range corrections forrocket motor temperature must be included.

Section IVNUlLCLEAR MUMTHODS

9-24. CHARACTERISTICSThe US Army howitzers are capable of

delivering the M753 rocket-assisted nuclearprojectile (203-mm), the M422A1 nuclearprojectile (203-mm), and the M454 nuclearprojectile (155-mm). Nuclear deliverytechniques have the same accuracies andtolerances as those for conventionalprojectiles. Conventional rounds serve as the

base rounds for both nuclear projectiles.Ballistic corrections are applied manually toHE firing data to determine the nuclear firingdata.

a. The M753 projectile has an integralrocket motor and is ballistically similar to theM650Ai HE rocket-assisted projectile. TheM753 projectile uses the same charge as theM650Ai projectile and is armed with theM735 electronic fuze. Because the M650Aland the M753 are ballistically similar, theM650 projectile can be used to register andderive GFT settings and position constantsfor an M753 nuclear mission. The M650projectile may also be used for observeradjustment with the M753 nuclear projectilefired in effect. All data computed for theseprojectiles are computed by use of FT 8-S-1and related graphical equipment. The rocketmotors in both projectiles may be fired eitherrocket on or rocket off.

b. The M422A1 projectile uses the M106HE projectile as the basic round on whichdata are computed. It is armed by the M542 or

the T316E3 time fuze. Nuclear corrections toHE M106 data are determined and appliedfrom FT 8-ADD-H-1.

c. The M424A1 high-explosive spotting(HES) round is used only in peacetimetraining to simulate a nuclear burst. It is notused in connection with either of the 203-mmnuclear projectiles. Firing table 8-ADD-I-1(for training only) is used to determinecorrections for the HES round from M106firing data in the same manner the FT 8-H-1is used to determine data for the M422A1round. If the M106 GFT technique is used, avalid M106 GFT setting must be available,and the target must be accurately locatedwithin transfer limits. For this technique, theHE to nuclear/HES charge correlation intable 9-26 is used. The M753 and M650projectiles use the M1, M2, and M188 orM188A1 propellants in the same manner.

Table 9-26. Charge correlation.

NUCLEARHE M106 M422A1PROPELLANTS PROPELLANTS

CHARGE CHARGE

1G, M1 1, 80

4G, Ml 2, 80

6W, 2 3, 80

8, 188 or M188A1 8, 188 or M188A1

9-38

S

S



FM 6-40

9-25. M753 DELIVERYTECHNIQUES

The three M753 delivery techniques thatcan be used are K-transfer, met + VE, and

observer adjustment. Regardless of thetechnique used, all data are determined to thesame accuracy as data in standard gunneryprocedures. Firing data are recorded on DAForm 5336-R (203-mm Nuclear Computa-tion Work Sheet for M753 Rocket-AssistedProjectile).

Note. Reproducible copies of new DAforms are in appendix J. Two-page formsshould be reproduced head-to-head.

a. K-Trans fe r. With the K-transfertechnique, registration corrections from anM650A1 RAP registration are used todetermine data for the nuclear projectile. TheM650 RAP data are modified to correct forballistic differences, propellant temperatures(both the propelling charge and the rocketmotor), and weight differences between theM650 RAP and the nuclear projectiles.

(1) Requirements. Use of theK-transfer technique requires a valid GFTsetting from an M650 registration. Normally,a high-burst registration is conducted. Thenuclear target must be accurately located andmust be within registration transfer limits.

(2) Accuracy. The accuracy of theK-transfer technique depends on the validityof the GFT setting. As the time from theregistration increases, the validity of theGFT setting decreases. Sudden changes inweather conditions will invalidate the GFTsetting.

(3) Speed. The K-transfer techniqueis the fastest method of determining firingdata.

b. Met + VE. When an M650 registra-tion is conducted, position constants shouldbe determined so that the subsequent met-to-target technique (chap 10) can be used.

(1) ]Requirements. Use of the met +VE technique requires that the target isaccurately located and tha t positionconstants are available. A current metmessage is also required. The requirementsfor position constants are the same as those

for conventional firing. Position velocityerrors include errors in the fifing chart, metmessage, and survey. The position fuzecorrection for the M582 fuze can betransferred from one position to another. The

position deflection correction can betransferred to a new location if commondirectional control exists between allpositions.

(2) Accuracy. When the position VEfor the M650 projectile is available, the met +VE technique is accurate. When registrationdata are not current or the target is outside oron the edge of the transfer limit, the met +VEtechnique is preferred. The accuracy dependson a current met message.

(3) Speed. The met +VE technique isslower than the K-transfer technique,because it requires the solution of a met totarget.

c. Observer Adjustment. Theobserver adjustment technique requires theobserver to adjust onto the nuclear targetwith the HE RAP and then fire for effect withthe M753 nuclear projectile.

(1) Requirements. The observeradjustment technique requires an observer inposition to observe the target. The observer

must adjust for range and deviation. Sincethe M753 projectile uses a proximity fuze,there is no requirement to adjust height ofburst; thus, a PD fuze may be used inadjustment.

(2) Accuracy. The accuracy dependson the observer's ability to adjust onto thetarget accurately.

(3) Speed. The speed of an observeradjustment mission depends on the speed ofthe observer in adjusting onto the target.Usually, observer adjustment is the slowesttechnique.

9-26. MANUAL DATA FORK-TRANSFERTECHTNEQUE (M753)

a. The RAP nuclear (M753) K-transfertechnique requires the use of a GFT settingand a GET deflection correction. The example(fig 9-26) uses the following GFT setting:GET B: Chg 7R, Lot MA, Rg 2O,000, E1630, Ti60.7; GFT Df Corr: L4, Tot Df Corr: L25.

9-39



FM 6-40

o r 5 E .,ATTACHED SG _o.... T G T A L - -- 0 .

ObovrIF/FFE/I/ S TtFC 78za TRYA LT53/K?Grid;

Poor: Dir Dis U/D _ _ _ _ _ _ V,,,,,,,,.. .....I , .,,. M-- - " ....... ChOfqgShift . . . : Dir - - -- /ft- --- I/ _ U D . . .

..

Figure.9-6.. Record.of.ire-K-trans..e techniquS. ..... . . . . . . . .

Figure 9-26. Record of fire-K -transfer technique.

b. The K-transfer technique requirescorrections for HE RAP and nuclearprojectile weights, propellant temperatures,and rocket motor temperatures and requiresthe determination of ballistic corrections.The ballistic corrections for the nuclearprojectile are applied to the final fuze setting,deflection, and quadrant elevation computedfor the HE RAP

c. Usually, the target information is sentto the unit in a message from higherheadquarters. It should contain the targetgrid location, altitude, and desired height ofburst.

d. The chart range and deflection to thetarget must be recorded on the record of fire.The FDO must decide which of the threetechniques he will use. The data in theexample (fig 9-26) are within transfer limitsof the high-burst location, and the GFTsetting is valid. Therefore, he will use theK-transfer method.

e. To compute the mission, the FDC musthave the propellant temperatures, projectileweights, and rocket motor temperatures ofthe HE RAP used in the registration. TheFDC also must have the weight, propellanttemperature, and rocket motor temperature ofthe nuclear projectile at the time the missionis being computed. For HE RAP, thetemperature of the rocket motor is assumed tobe the same as the temperature of thepropellant. Although the M753 nuclearprojectile uses the same propellant as theM650, the propellant used to fire the M753and that used to fire the M650 may be storedseparately. Therefore, provisions are made inthese calculations for variations between

propellant and rocket motor temperatures forthe nuclear projectile and those for the HE

RAP. The differences in propel lanttemperatures, projectile weights, and rocketmotor temperatures must be determined; anda corresponding range correction, in meters,.must be applied to the chart range. The resultis a corrected range at which the firing datawill be computed.

f. DA Form 5336-R is used for 203-mmnuclear computations (M753 projectile).

(1) Use blocks 1 through 8 (fig 9-27)when determining entry range. An entryrange is necessary to determine unit

corrections for propellant temperatures,projecti le weights, and rocket motortemperatures. Use the same procedure todetermine entry range as that used forsolving a met.

STDU1 VALUE

I ALTITUDE FTARGET 10 METER) A12 HEIGHT OF BURST ABOVE TARGET 0iMETER) -,15

3 ALTITUDE OF BURSTI + ff ) 1 METER)

4 ALTITUDEOF BATTERV 1METER) 3 9HEIGHT OF BURSTI

5 AB3OVE GUN) F31 (1METER) c5

6 CHART RANGE TO TARGET (10 METERS) 1

7 -COMPLEMENTARY RANGE (TABLE B) (I METER) + 8ENTRY RANGE)( + F71

FI~nz~ [1METERj) 100 METERS) C 170

Figure-9-27. Determination of entry range-K-transfer.

9-40



FM 6-40

(2) Use blocks 9 through 13 (fig 9-28)when determining corrections for differencesin propellant temperatures, projectileweights, and rocket motor temperatures.

(a) Propellant temperature. Deter-

mine the change to muzzle velocity tocompensate for the change in propellanttemperature (table 9-27). Determine thedifference (increase or decrease) between themuzzle velocities (in fig 9-28, -0.4 meter pe rsecond from -0.6 meter per second = adecrease of 0.2 meter per second). The unitcorrection factor (table F at entry range18700,' column 10, for decrease) is +36.6.Determine the correction, in meters, for thechange in propellant temperature bymultiplying 0.2 x +36.6 = +7.32 +7.

ENTRY RANGE ( F61+ [D )I

IS 7A/ [1,METER]), (100METER) /4570C

A MUZZLE VELOCITY (TABLE E)9 (NUCLEAR PROJECTILE POW ER (01 METER .- 0TEMPERATURE - OF)) PER SECOND)

A MUZZLE VELOCITY TABLE E)

(HIGH-EXPLOSIVE/ROCKET-

10 ASSISTED PROJECTILE POWDER ( EE f

TEMPERATURE I oF]) PER SECOND)

11 DIFFERENCE IF9_1 - IMI(0.lDECREASEINCREASE

UNIT CORRECTION2 (TABLE F COLUMN 10/ 11) (01) 6 ,,.613 CORRECTION FOR PROPELLANT

CHARGE TEMPERATURE17METERI f /

Figure 9-28. Corrections for difference inpropellant temperature-K-transfer.

(b) Projectile weight. The weight ofthe HE RAP is measured in squares, with 4squares being standard. The weight of thenuclear projectile is measured in pounds,with 200.0 being standard. Firing table 8-S-1

gives corrections in range in terms of squareweight. To calculate a correction for a changein weight (fig 9-29), convert the weight of theHE RAP to pounds. Then find the differencebetween that weight and the weight of thenuclear projectile in pounds. Convert thatdifference to squares. Then determine therange correction. The standard weights of theHE RAP are on page VI of the introduction ofFT 8-S-1. From the table, it is possible to inferthat a difference in weight of 1 square equalsa difference of 2.5 pounds.

T4 NUCLEAR PROJECTILE WEIGHT (0 1 POUND 0

HIGH-EXPLOSIVE /ROCKET-

15 ASSISTED PROJECTILE WEIGHT O U II I)PAGE VITFTI101POUND) /9q /7

16 DIFFERENCEI 101 POUND

~I DECREASE NCRE

17 DIFFERENCE IN SQUARE (0 117 WEIGHT(gJ - 2 5) DECREASE NCREAS

18 UNIT CORRECTION (TABLE F, 1M ECOLUMN 18 19) (1 METER) + 4

CORRECTION FOR PROJECTILE

19 WEIGHT (I]

1- 11 METER) I '-NUCLEAR PROJECTILE ROCKET

20 MOTOR TEMPERATURE RANGECORRECTION (TABLE E ) (0 ME TER)

)AFORM XXXA-R SEP 84 (CONFIDENTIAL

Figure 9-29. Corrections for projectile weight-K-transfer.

(c) Rocket motor temperature. De-termine the difference (increase or decrease)between range corrections by using FT 8-S-1,table E.1, and by calculating the changebetween HE RAP and rocket-assistednuclear projectiles (fig 9-30 and table 9-27).The range correction for HE RAP rocket

motor temperature (+670 F) is 0 when usingthe nearest listed temperature and range. Thenuclear range correction is 16 meters at a

Table 9-27. Example data.

PROJETILEROCKETPROJECTILE PROPELLANT MOTORWEIGHT TEMPERATURE TEMPERATURE

HE/RAP: 3 squares +670F +670 FNuclear: 201.0 pounds +650 F +650 F

9-41



FM 6-40

temperature of +650 F. The difference in rangefrom HE/RAP to nuclear is 0 to +16, or +16meters. For rocket off missions, this step isdeleted.

Figure 9-30. Corrections for rocketemperature-K-tran

(d) Corrected range. Detcorrected range as shown in figuadding the corrections, in meteiprojectile weight, propellant te:and rocket motor temperature tochart'range to the target and expitotal to the same accuracy as tharange (10 meters). The corrected rbe determined before any values ccan be determined.

Propellant temperaturecorrectionProjectile weight correctionTemperature correction-rocket onInitial chart range

Corrected range

t motorsfer.

elevation with the current GFT setting. Withthe corrected range set under the MHL, readthe elevation under the elevation gage line(block 24). Determine site and angle of sitewith the GST, and enter the data in block 25.

Add site to elevation to determine HE RAPquadrant elevation (block 26).

Figure 9-32. Determination of HE/RAPquadrant elevation- K-transfer.

ermine the (4) Use blocks 27 through 31 (fig 9-33)tre 9-31 by when determining fuze settings. Determiners, for the angle of site with the GST, and enter the datamperature, in block 27. The fuze setting to fire is the M735the initial electronic time setting corresponding to

ressing the elevation plus comp site plus ballisticit for chart correction from part 2, table B, of the tabular-ange must firing table. Determine elevation plus comp)n the GFT site (block 28) and place that number under

the elevation gage line. Read the fuze settingunder the time gage line. The ballisticcorrection to be applied to the M735 electronic

+7 meters time fuze is in part 2, table B, of the tabular+48 meters firing table.

+16 meters+ 18,720 meters

18,791 meters18,790 meters

23 CORRECTED RANGE JO 7fli4

( + H + F A+V2](10OMETERS) / 7

EL 1 I (HIGH-EXPLOSIVE

Figure 9-31. Corrected range-K-transfer.

(3) Use blocks 24 through 26 (fig 9-32)when determining HE RAP quadrantelevation. Determine the HE RAP quadrant

27 AN(te 5- SITE(27 A O FST OTANDSCALESI J11MILl)

ELEVATION. COMPLEMENTARY 5528 ANGLE OF SITE, 27 10 MILl

.... L

FUZE SETTING .- HIGH EXPLOSIVE29 ROCKET ASSISTED PROJECTILE IML

GFT SETTING) (Oil 5

BALLIS TIC FUZE CORRECTION . ..

30 FOR NUCLEAR PROJECTILE "A(PART 2. TABLE 8110 1)

31 FUZE SETTING TO'FIRE '... L

...................

Figure 9-33. Determination of fuze setting-K-transfer.

9-42

S

7~rt- j

S

p



(5) Use blocks 32 through 35 (fig 9-34)when determining deflection to fire. Add aballistic correction from part 2, table A. Addthe deflection correction and ballisticcorrection to the chart deflection as shown.

32 CHART DEFLECTION TO TARGET 1 MILI 298DEFLECTION CORRECTION aFT

33 DEFLECTION CORRECTION

- DRIFT-

ELEVATION [2-- .L& --.. 1 0MIL)

BALLISTIC DEFLECTION CORRECTION

(PART 2 TABLE ) I10 1 MIL]) 11 MILl

S DEFLECTION TO FIRE .. .... o l

35 U2. P . - , 0MIL)

Figure 9-34. Determination of deflection-K-transfer.

(6) Use blocks 36 through 38 (fig 9-35)when determining nuclear quadrantelevation. Determine the QE to fire byapplying a ballistic correction from part 2,table A, to the HE QE already determined.The fire commands are now complete.

Figure 9-35. Determination of nuclear quadrantelevation- K-transfer.

9-27. MET + VE TECHNIQUE

a. The computation of met + VE fornuclear missions requires a fuze settingcorresponding to elevation plus comp site anda rocket motor correction. As in theK-transfer technique, correct the ballistic

differences between the M650 and M753projectiles by using values from part 2 of thetabular firing table.

b. A message is received with targetinformation for the nuclear mission. Theexample includes a height of burst of 95meters. Use the met + VE technique.

c. To determine the data to fire, solve amet to target by using position constants andthe most current nuclear data (propellanttemperature, rocket motor temperature, andprojectile weight) (fig 9-36). If a quadrantelevation can be implied, use table A of theTFT to determine the met line number. If noQE can be implied, use table B.

METDATA ORRECTIONSHEETFor oe of thia form, on FM -40; proponent agency Is TRADOC.

BATTERY DATA MET MESSAGE

C"fa D E -rp0

Zi Rdi-lZTIT U O E T Y P E MESSAGE OCTANT RAEUNIT

..... 0 ....TE TINE r ALT- O . PEEALFOT R 1.23 C

ALTOFMOCINWeNO. 7WINO4001% WINO WEEGAliR TEOR AIR DEfNG??

NSTS$IMOMjOP AMd C') &bCCONNECTION- -

LT.... -eoeTCT' I 2. COENECTEVALE

REIGN. OF NUNS - 95'ANOVE AROT

AL.TOFSY 5o 7

(how)v -or ..........I.

PICT T 0D I R E C I O N 0T F119 ORRan

Ofir

~.E8O* 1WZ. NNOTG cools lG [ir~l~.,zz-4- --------- m

COMPUTATION F VIE

CHANGE O MV'FFOR PTWEOF s

I Av I

TOA Mo,8=C*,o

IET ANGE ta 6CONRECTIOOI

wsj iOTTAL RANGE --ICORN CCIOR 1

s a E T UZE CORRECTION

FRM 'ORA CT % PLUS W1MS

5 AN D?-.-

A VRANGE WIND

AIR EMP Il

AIR . ..N IT I

p~o .,,o " jCORRECTON F

I R M O spgl~ UNITLIMj

1.__ _

MTFZ CORCOWWRE C TIOG4A

NL0FT EI CW' __RP__Z ]?AVGI E.COQ.Ij

lICE? I - . . .ENE .CInOAT1 F"GTZCF

Figure 9-36. Manual data for met + VE technique.

9-439-43

U-

i i

I INIM LI I

C.ROU INO,10

r- L

p op

r di

V,

TOTAL RANGECORRECTION 4 0

MIS- 2 = Awn wir

10

IOAT -' TIME1--(, -.5



CHART RANGE17,750 METERS

+140 METERSTOTAL RANGE CORRECTION

CORRECTED RANGE17,890 METERS

Figure 9-37. Corrected range-met +VE.

d. After the met is solved, perform theremainder of the computations on DA Form4200. To determine a corrected range, applythe total range correction (from the met) tothe chart range (fig 9-37).

e. Determine the HE RAP quadrantelevation by placing the MHL over thecorrected range (block 4). Then compute andadd site (fig 9-38). Determine angle of site andenter the data on the form.

f. Determine the fuze setting for HE RAPby placing the MHL over elevation plus compsite. Add the total fuze correction from themet (fig 9-39).

1 HEIGHT F B ABOVE GUN MET FORM) (1 METER)

2 CHART RANGETO TARGET (10 METERS) /7,7503 TOTAL RANGE CORRECTIONMET FORM) (10 ETERS) +190

4 CORRECTED ANGE)( + Wn3 (10 METERS) /7 6 9 05 ELEVATION , vUSE MANUFACTURERS HAIRLINE) (1MIL) 9y

6 L IE G Tn V RTC L ITERVALI....RNGE.2... .IL .

Figure 9-38. Determination of HE/RAP quadrant elevation-met + VE.

VERTICALINTERVL1 AT R 11 MI

71 OUAORANTELEVATIONFOR IGH-EXPLOSIVE/ROCKET-ASSISTEDPROJECTILE5] [67 11ML)

~8 ANGLE OF SITE GFT. C- AND D-SCALES) (1 MIL) 4

9 ELEVATIONCOMPLEMENTARYANGLEOFSITE 0WI1 MIL) C.9510 FUZE ETTING (USE ANUFACTURERSHAIRLINE) 10 1MIL) 9 511 TOTALFUZE CORRECTIONMET FORM) (1.1 IL)

12 FUZE SETTING OR HIGH-EXPLOSIVE/ROCKET-ASSISTEDPROJECTILE) - 1 1 101MIL) 2.1 *.I

F i u 9 e t e2TABCE

Figure 9-39. Determination of HE/RAP fuze setting-met + VE.

OLDOUT 9-43

M 6-40

9-44



FM 6-40

g. To determine the data to fire, apply theballistic corrections from part 2, tables A andB, to the HE RAP deflection, fuze setting, andquadrant elevation. Enter part 2 data atitems 13, 17, and 19 (fig 9-40 and 9-41).

I ote. The fuze setting to fire is the fuzesetting for HE RAP plus the ballisticcorrection (fig 9-40).

h. Determine the deflection to fire byapplying the total deflection correction fromthe met and the ballistic correction to thechart deflection (fig 9-41).

i. The quadrant to fire the HE RAP roundhas already been determined. Determine thenuclear QE by applying the ballisticcorrection from part 2, table A. The firecommands are complete for this mission (fig9-41).

j. There may be rare occasions when aposition VE is not available and a

registration or observer adjustment isimpossible. When this happens, extract aposition VE from the approximate loss inmuzzle velocity table on page IX of the firingtable. Enter the table with the ordnance-provided pullover gage reading (preferred

method) or equivalent full charge erosionrounds.

9-28. OBSERVERADJUSTMENTTECHNIQUE

a. If the requirements for the met +VE orK-transfer technique cannot be met, anobserver may be used to adjust the HE RAPonto the nuclear target. Shell nuclear is firedin effect. If the observer adjustment

technique must be used, an observer will be inposition to observe the target. To adjust, useM650 projectiles fuzed with M577 fuzes. Thefuze settings are not adjusted, because theycan be determined from the MPI registrationscale on the GFT for M735 fuzes.

Figure 9-40. Determination of nuclear fuze setting-met + VE.

16 TOTAL. DEFLECTION CORRECTION (MET FORM) (1 MIL) L 3 0

17 BALLISTIC DEFLECTION CORRECTION (PART 2. TABLE A) 1 [0.1 MILl) 1 MIL) 0

18 DEFLECTION TO FIRE( H +• rl6 + (1MIL)

19 QUADRANT ELEVATION FOR HIGH-EXPLOSIVE/ROCKET-ASSISTED PROJECTILE 07 (1 MIL)

20 BALLISTIC CORRECTION FOR NUCLEAR PROJECTILE (PART 2. TABLE A) (0 MIL) + L

21 QUADRANT ELEVATION TO FIRE F91+ 0 M)) I1)

Figure 9-41. Completion of fire commands-met + VE.

9-45



FM 6-40

b. To determine nuclear firing data,recompute the site to include the height ofburst, and determine the fuze settingcorresponding to elevation plus comp site.Recompute the new HE RAP quadrantelevation with the new site. Entry

argumentsinto the ballistic correction tables of the TFTare the new HE RAP quadrant elevation andthe M735 fuze setting. If there is a differencein projectile weight and/or temperature, anentry range must be computed by usingvertical interval, chart range, and part 1,table B. The final chart range must bemodified by the range correction for projectileweight, propellant temperature, and rocketmotor temperature before the HE RAPquadrant elevation can be determined. Thisprocedure is the same as that for theK-transfer technique.

c. Consult the BCS job aids to determinefiring data for the M753.

d. Consult the FADAC job aids todetermine firing data for the M650/M753projectile combination.

9-29. M422A1 DELIVERYTECHNIQUE

a. The only authorized computationtechnique for the M422A1 nuclear projectileis to use FT 8-ADD-H-1 to determineballistic corrections for the round. FT8-ADD-I-i is used in computing data for theM424A1 HES t raining round. Bothprojectiles use the same technique. Only theaddendum changes. There is no GFTequipment for these projectiles. Anypreviously used equipment is now obsolete.All HE data in this section use FT 8-Q-1.

Correction factors from FT 8-ADD-H-i areapplied to the HE data to determine M422A1firing data.

b. When an HE GFT setting and GFTdeflection correction are used, thefire-for-effect data are modified. The fuzesetting, deflection, and quadrant elevationare modified by corrections from the firingtable and the appropriate addendum. Duringtraining missions, the M564 time fuze may beused instead of the M582 fuze. The proceduresare the same, except that the expecteddelivery accuracy may be less because of thelarger M564 fuze probable errors.

c. Range corrections are computed for thenuclear propellant temperature and weightdifferences. These corrections account forchanges in muzzle velocity.

(1) Projectile weight range correctionsare listed in FT 8-Q-i, table F, columns 18and 19. Enter the appropriate charge at thenearest listed range to the target. This tablelists range corrections, in meters, for adifference of 1 square weight. Table 9-28 liststhe square weights of the HE, nuclear, andHES projectiles based on weight in pounds.

(2) Propellant temperature correctionsare in table C of the addendum. Enter thetable at the nearest listed range and thenearest listed temperature. Do not interpolatewhen using this, table. If the differencebetween HE and nuclear (HES) propellanttemperatures is greater than +10' F,recompute the GFT setting by using thenuclear (HES) temperature in the subsequentmet (chap 10). If the difference is less than+100 F, use the current HE GFT setting.

(3) Algebraically add the rangecorrections for propellant temperature and

Table 9-28. Pound weight to square weight.

FUZED WEIGHT IN POUNDS

HIGHSQUARE EXPLOSIVE NUCLEAR HIGH-EXPLOSIVEWEIGHT (M106) 11 M422A1 SPOTTING M424A1

3 197.5 238.3 to 240.7 238.3 to 240.741 200.0 240.8 to 243.2 240.8 to 243.2

5 202.5 243.3 to 245.7_ 243.3 to 245.7Sta nda rd.

9-46

S

S



projectile weight to the chart range todetermine the corrected range.

d. Site is determined between the piece tofire and the target (including height of burst).Since the vertical interval will normally begreater than 100 meters, comp site must bedetermined and applied. Elevation plus compsite is used to determine the fuze setting forthe M582 fuze.

e. The HE QE is determined byalgebraically adding elevation plus site.

f. The HE deflection is determined byalgebraically adding chart deflection plusdrift plus the GFT deflection correction.

g. The HE firing data are corrected to

compensate for differences between the twoprojectiles.

(1) Enter table A of the appropriatecharge in the addendum. Use the HEquadrant elevation, expressed to the nearestlisted value, and obtain the quadrantelevation and deflection ballistic correctionsfor shell nuclear (HES).

(2) Enter table B of the addendum withthe HE fuze setting. Obtain the correction tofuze setting for the nuclear (HES) projectile.

(3) Algebraically add the correctionsto the appropriate HE data to determine thenuclear (HES) firing data.

h. Figures 9-42 and 9-43 show acompleted record of fire and a completed DAForm 5337-R (203-mm Nuclear Computa-

tion Work Sheet for M422A1). The following'data are used for computation.

RECORD OF FIRE

CALL ORFIRE F

Observer AF/FFE/IS/S Tqt 100/R

Grid: tCROM ccAssdr4eP 5G/RPolar:Dir Dis U/C V20/RVA

Shift Dir L/R +1. U/D.. Si--10 I'0m iN OBCorr

FIREORDER Df Corr Si

INITIALIRE OMMANDS VFM MF*J fRg L.5 ChtDl 9 El

SpInsrA Ch Q o " C h q 3 FzTJTi -- "-O&MWO T4 PER TIin Eff Armmo sp

TgoinPr ior i ty Frn

Tgt Location UFiringi SUBSEQUENTIRE OMMANDS01 Unit

Dir, MF Dev Rg NOB MF, Sh, FS Ti Chart [DI Csrr D Chort NoB SiTFh, F Corr Chg, Ft Corr Of 1 ( ired Rg -Corr

... . .-. --

Fiue9-2 iom ltd reod of rire. yp

.. ... ........ ......... ..... . .. -: - . . .. .......

... ... ================================......... .

............ ~ii:.... ... .................................. . ::::::::::::::::::::..... .-. . ...... . :: :::::::::::::::::::::: .. .. ... . ..... .... ................:::::::::::::: . .... :::::::::::::::::::::::............i i,:i~i ..... '" '......: :'

. ....... ..................... ; i~ : i: ===================..

..... . . . .. ... ....

Figure 9-42. Completed record of fire.

203-MM NUCLEAR COMPUTATIOFor use of this form, see FM6-40; prOpOnent agency ts TRADOC

KNOWN D

TARGET ALTITUDE I

-LLANT EMPERATURE HIGH-EXPLOSIVEPROJECTILEIOF Ut) 4 j17 EIGHT ,(l-- I

ENTERTHE NTRODUCTION TO FT 8-ADD-H-1 FOR CORRESPONDING CHARGi

ELEVATION Tl E GFT QEFLECTION

0 ELEVATION TIME . GFT EFLECTIONQ// J,5 CORRECTION

37ATA

DATEHART RANGE

i/, , ,50NUCLEAR PROJECTILE WEIGHT TIME

239.8 ; 3 .

H

,2.zO

i FROM 1 ABOVEI I ff 2

STEP PROCEDURE VALUE

3 RANGE CORRECTION FOR PROPELLANTTEMPERATURE (FT -ADD H 1, TABLI C).

4 RANGE CORRECTIONFOR PROJECTILE EIGHT DIFFERENCE (FT 1, TABL F. ""

5 F +W+ oCHART.RANGE=CORRECTEDANGE. /'I SI Z1/50

6 ADDTARGETALTITUDE ANDHEIGHTF URST. (F o1 CJ SI/zCLJ 5GW)

7 SUBTRACTBATTERYLTITUDEFROM STEPH6 ERTICAL INTERVAL -- 98 DETERMINE SITE CORRESPONDING TO STEPW( G ST).47

9 1FVERTICAL INTERVAL IS EATE THANOR QUALTOI100 USE C ANDOD C ILES TO DETERMINFANGLEOF SITE,IF ERTICAL INTERVAL IS ESS THAN 100, GO TO STEP E-.]+ L+

10 SUBTRACT STEP 9 FROM STEP [ COMPLEMENTARYANGLE OF SITE

11 DETERMINE ELEVATION--CORRECTED RANGE STEPW_} .

12 DETERMINE'FUZE SETTING-ELEVATION + COMPLEMENTARY ANGLE OF SlIt STEPtl0 z/O /7

13 ADD STEPS 8 AND r-1= IGH -EXPLOSIVE QUADRANT ELEVATION•1r7

141

1 CORRECTIONS TO HIGH EXPLOSIVEQUADRANT ELEVATION FOR SHELL NUC EAR (FT 8 ADD H 1. ABLEA).16 CORRECTIONSTO NIGH EXPLOSIVE DEFLECTION OR SHELL NUCLEAR FT B D D H 1 TABLEA) R 4 . O

17 CORRECTIONS TO HIGH EXPLOSIVE FUZE FOR M591 FUZE (FT ADD H 1 T 1 BLE )

18 ADD STEPS 12ANDW71-] UCLEAR TIME M591

19 ADD STEPS 1 AND fl NUCLEAR DEFLECTION•06

20 ADD STEPS13 AND[IN NUCLEAR QUADRANT ELEVATION -

DA FORM 5337-R SEP 84

FM

9-47 FOLDI

N WORK SHEET FOR M422A1

(CONFIDENTIAL WHEN FILLED IN)

Figure 9-43. Completed DA Form 5337-R.

9-47



FM 6-40

(1) Battery B has just conducted aregistration. The unit receives a nuclear firepission. The mission message gives the

tirget location, altitude, and height of burst.The fire order and initial fire commands are

nnounced. The current GFT setting is GF T:rChg 6, Lot XY, Rg 10950, El 411, Ti 33.3;

9FT Df Corr: L9. Charge 6WB, M2corresponds to charge 3, M80 propellant.Other known information is as follows:

MSO propellantchargetemperature

M2 temperature

M422A1 projec-

tile weight

M106 weight

Chart range totarget

Chart deflection

Vertical interval

+380 F+470 F

239.8 pounds

4 squares

11,450 meters

3,289 mils

+247 meters

(2) Determine and apply rangecorrections for propellant temperature andprojectile weight to the chart range. Enter FT8-Q-1, table F, charge 6, at the nearest listedrange (11,400). From columns 18 and 19,extract the range correction for a change in 1square weight (decrease -19 meters, increase+20 meters). Determine the difference insquare weight from HE to nuclear using table9-28.1 E weight - nuclear weight (239.8) =I change in square weight

1 4 squares - 3 squares = decrease of 1square

(a) Multiply the -19 meter decreasesquare weight factor by 1 (square difference)0 yield a -19 meter range correction for

rojectile weight change.

(b) Enter table C of the addendumyith the temperature expressed to the nearestlisted value (+48 +50) and the range

xpressed to 11000. The range correction isetermined to be +22 meters.

(c) The corrected range is:

Chart rangePropellant temperaturerange correction

Projectile weightcorrection

Corrected range

11450

+22

-19

1145311450

(3) Now determine site by using chartrange (11450). The vertical interval is +247meters. Site is +26 mils.

(4) Since the vertical interval is greater

than 100 meters, determine and add comp siteto elevation to determine the fuze setting (site[+26] - angle of site [+22] = comp site [+4]). Fuzesetting is 35.7 corresponding to elevation pluscomp site (447).

(5) Determine high-explosive QE byadding elevation plus site (469 mils).

(6) High-explosive deflection is 3,310mils (chart deflection 3289 +drift L12 + GFTdeflection correction: L9).

(7) Correct the HE data by applying theballistic corrections from the addendum.

(a) From table A, extract the QEcorrection (-45.2 mils) and the deflectioncorrection (R4.0) (fig 9-44).

(b) Enter table B with the HE fuzesetting (35.7) (use lines 34.6 through 36.8),and extract a correction of -0.9.

(8) Complete, announce, and record therest of the fire commands as shown in figures9-42 and 9-43.

9-30. M422A1 COMPUTERPROCEDURES

The computer solution of firing data for theM422A1 and M424A1 projectiles cannot bedetermined. High-explosive data can becomputed, and the ballistic corrections forshell nuclear are applied manually. Consultthe job aids for specific instructions.

FOLDOUT 10-47 9-48



TABLE A

QUADRANT ELEVATION

FT B ADO-H-I

PROJ. ATOMIC, 422AIFUZE, MT. M542

12 3

QUAD ELEV CORR TO CORR TOFOR QUAD ELEV DEFL

PROJ. M106 FOR PROJ FOR PROJ.WITH CHG 6W MP42AI M422AI

MILS MILS MILS

1175 1093 R4.3

1180 10.1 R4.51185 9.8 R4.71190 9.6 R5.01195 9.3 R53

1200 9.1 R5.7

1205 8.q Re.l

1210 8.7 R6.51215 8.5 R7.01220 8.2 R7.b

1225 8.0 Rb.2

1230 7.8 R9.01235 7.6 R9.91240 7,5 R1O,91245 7.3 R12.0

1250 7.1 R13.4

1255 6.9 R14.91260 6.8 RlbS.81265 6.6 R19.01270 6.5 R21.b

1275 6.4 R24.8

1280 6.2 R2b.6

FT 8 ADD-H-1

PROJ. ATOMIC. M422A1

FUZE. MT. M542

TABLE 8

FUZE SETTING

M582 CORRECTIOV TOFUZE SETTING FUZE SETTING

FOR PROJ. Mi06 FOR PROJ. 4422AIWITH CHG 6W WITH FUZE M54i2

11.3-12.3 -0.9

12.4-14.0 -1.014.1-16.1 -1.1

16.-19.2 -1.2

19.3-27.4 -1.327.5-30.3 -. 0230.432.4 -10132.5-34.5 -1.0

34.6-36.8 -0.9

36.9-39,4 -0.839.5-47.7 -0.747.8-49.0 -0.349.1-50.0 -0.9

50,1-50,7 -1.0

50.8-51.3 -1 151.94-51.9 1.252.0-52.4 -1.352.5-52.8 -1.4

52.9-53.2 -1. I

53.3-536 -1.5 1

53.7-539 -1.7 '54,0-54.2 -1.954.3-54.5 -2.9

54*9-55.0 -2.1s4.9-ss5*o55.1-55.2 -.55.3-55.5 -2.355.6-55.7 -2.4

55.8-55.9 -2.5

56.0-56.1i -2o6.56.2-56,3 -2.7

56.4 -2.B56,5-56.6 -2.9

S67 56.8

Figure 9-44. FT 8-Q-1, tables A and B.I

9-49 FO

CMARGE3

FM

-3.0

9-49



FM 6-40

9-31. 155-MM HOWITZERNUCLEAR GUNNERY

The US nuclear inventory includes a155-mm nuclear projectile in addition to the203-mm nuclear projectiles. The 155-mmnuclear round consists of the atomicprojectile M454; a propellant charge M206,M207, or M197; a sequential timer M32E1;and a fuze system that has MT and VToptions. The VT fuze is armed by thesequential timer and has a high or low optionthat must be selected.

9-32. 155-MM NUCLEARDELIVERYTECHNIQUES

Currently, K-transfer is the deliverytechnique for the 155-mm nuclear round. Thefiring data for this technique are determinedto the same accuracy as data for conventionalgunnery. With the K-transfer technique, anHE GFT setting is used to determine HE datato the target. These data are then modified forthe nuclear rdund.

Note. Although the K-transfer technique

is preferred, the met correction and observeradjustment techniques are still valid. Forthese techniques, use DA Form 4504 and DAForm 4505 (155-mm Nuclear Computation-Met Correction Technique).

a. Requirements . Use of the K-transfer technique requires a valid HE GFTsetting. The target must be accurately locatedand must be within the GFT setting transferlimits. In applying HE corrections, the HEcharge to nuclear charge correlation in table9-29 is assumed.

b. Accuracy. The accuracy of theK-transfer technique depends on the validityof the GFT setting. Changes in weather willinvalidate the GFT setting. A disadvantageof the K-transfer technique is the errorinduced by applying HE data in determiningfiring data for the nuclear projectile. Use ofHE charges 4 and 5 green bag registrationcorrections is preferred to use of charges 4and 5 white bag, because the differencesbetween the standard muzzle velocities forM3A1 (GB) and M206 are less than thedifferences between M4A2 (WB) and M206.

9-33. MANUAL PROCEDURESFOR SHELL NUCLEARBY USE OF THE GFTAND TFT

When an GFT setting is determined and anuclear mission is anticipated during thetime that the GFT setting is valid, a nuclearstandard GFT corrects the HE GFT to astandard projectile weight and a standardpowder temperature. The nuclear standardGFT setting is used only when a nuclearmission is received.

EXAMPLE:The following HE GFT setting was deter-mined:

GFT A: Chg 4, Lot XY, Rg 5140, El 335, Ti18.9 FT Df Corr: R5; Tot Df Corr: L2The propellant temperature at the time theHE GFT setting was determined was +420F.The propellant weight of ammunition lot Xis6.The lazy Z from the HE registration is asshown in figure 9-45.

FOLDOUT 9-49

Table 9-29. HE-to-nuclear charge correlation.

M109A2/A3M114A1,M198 M114A1 M109A2/A3,M198

HE, M107 NUCLEAR PROJECTILE NUCLEAR PROJECTILEPROPELLANTS M454 PROPELLANTS M454 PROPELLANTSCHARGE CHARGE CHARGE

4(GBorWB) 1 (M206) 1 (M206)5(GB or WB) 2(M206) 2(M206)7-(WB) 3 (M207) 3(M197)

I

9-50



FM 6-40

TOTAL RANGECORRECTION

5380

18.9

335140

19.9

TOTAL FUZE CORRECTION

51

LI -1.0 JFigure 9-45. Lazy Z-HE registration.

a. The computer determines the corrected

total rangecorrection for a nuclear standard

GFT setting.

(1) Steps used to correct a standardpropellant temperature.

(a) To correct elevation to standardpowder temperature, the computer enterstable E of the HE TFT at the appropriatecharge and extracts the effect on muzzlevelocity due to propellant temperature at thetime of the registration.

(b) The computer enters table F with

chart range to the nearest 100 meters for theappropriate charge and range and extractsthe range correction for a change in muzzlevelocity of 1 meter per second (column 10 or11).

(c) The computer multiplies the effecton MV due to propellant temperature by therange correction for a change in MV todetermine a range correction value based onstandard propellant temperature.

(2) Steps used to correct elevationto standard projectile weight.

(a) The computer determines thesquare weight difference between theregistered projectile and the standard weight.

(b) The computer enters table F withthe GFT range and extracts the rangecorrection to correct for a change of 1 squareweight.

(c) The computer multiplies the rangechange for a square weight difference of 1square by the square weight change.

9-51

(3) The computer adds the range cor-rection determined for powder temperature tothe range correction determined for projectileweight and expresses this value to the nearest10 meters.

(4) The computer then adds the totalrange correction value determined inparagraph (3) above to the total rangecorrection determined from the lazy Z in theregistration and begins to build a nuclearstandard GFT setting.

b. The computer determines the correctedtotal fuze correction for a nuclear standardGFT setting.

(1) Steps used to correct time tostandard propellant temperature.

(a) Thecomputer enters table J with

the corrected time determined in the lazy Z(fig 9-45) and extracts correction factors formuzzle velocity and projectile weight.

(b) The computer multiplies the MVcorrection factors by the change to muzzlevelocity determined in paragraph (a) above.

(2) Steps used to correct time tostandard for projectile weight.

(a) The computer multiplies the fuzecorrection factor by the change in projectile

weight to determine the fuze correction factorfor projectile weight.

(b) The computer adds the fuzecorrection factor for propellant temperatureto the fuze correction factor for projectileweight expressed to the nearest tenth. Thisvalue is the total fuze correction.

(c) The computer now adds the totalfuze correction value to the total fuzecorrection determined from the lazy Z in theregistration and completes the nuclearstandard GFT setting.

(d) The computer records the nuclearstandard GFT setting.

9-34. NUCLEAR FIREMISSION PROCESSING

When a nuclear fire mission is received, thefiring data are computed by use of the nuclearstandard GFT setting to determine HE data.



FM 6-40

Ballistic corrections are then applied by useof FT 155-AJ-2.

a. Upon receipt of a nuclear fire mission,the FDO issues his fire order on the basis ofthe information in the classified message.

b. The HCO determines and announceschart data to the target. The VCO determinessite.

c. The computer announces initial firecommands.

d. The executive officer reports thenuclear propellant temperature and thenuclear projectile weight.

e. The computer determines the rangecorrection for nuclear propellanttemperature.

(1) The computer enters FT 155-AJ-2,table E, and extracts the effect of propellanttemperature on muzzle velocity.

(2) The computer enters table F with theappropriate change and range to the targetand extracts from column 10 or 11the rangecorrection for a change in muzzle velocity of1meter per second.

(3) The computer multiplies the effecton muzzle velocity due to propellanttemperature by the change in range for achange in muzzle velocity of 1 meter persecond. This determines the range correctioncompensating for nuclear propellanttemperature.

f. The computer determines the rangecorrection for nuclear projectile weight.

(1) The computer determines thedifference between a standard nuclear

projectile (120.4 pounds) and the nuclearprojectile to be fired.

(2) The computer enters FT 155-AJ-2,table F, with range to the target and extractsfrom column 18 or 19 the meter correction fora 1-pound difference in projectile weight.

(3) The computer multiplies theprojectile weight difference by the correctionvalue of a 1-pound weight difference.

g. The computer determines the totalrange correction to compensate for projectileweight and propellant temperature.

h. The computer adds the total rangecorrection to the range to the target.

i. The computer now determines HE databy use of the nuclear standard

GFT settingand the corrected range.

j. The computer enters table 0 with thehigh-explosive QE and extracts and appliesballistic corrections to HE time, deflection,and quadrant.

k. The computer enters table K with thenuclear propellant temperature and theintermediate time setting and extracts atemperature correction to the nuclear fuze.

Note.If the mission called for fuze time ineffect rather than fuze VT, the corrected time

setting would be the time fired.

1. The computer enters table L with thecorrected time setting and the temperature ofthe time fuze (nuclear propellanttemperature) to determine the backoff timefor firing the nuclear fuze with the VT option.

Section V.COPPERHEAD

9-35. CHARACTERISTECSa. The cannon-launched guided

projectile (M712 Copperhead) is ahigh-explosive antitank 155-mm projectile.It is significantly heavier (137 pounds) and

longer (54 inches) than the standard 155-mmhigh-explosive projectile. The nose of theprojectile houses a semiactive laser seeker ina clear plastic cone. The body contains finsand wings, which deploy in flight and allowthe round to maneuver. The projectile

9-52

S



FM 6-40

PULSE REPETITION FREQUENCY CODEAND TIME SWITCHES (5) WING SLOT (4) FIN SLOT (4)

I OBTURATOR

Figure 9-46. Copperhead projectile in shipping configuration.

requires no special assembly or testing at thefiring site. The projectile is shipped andstored in a sealed container (fig 9-46).

b. The Copperhead round can be fired ineither the ballistic mode or the glide mode.The primary mode, for use in the minimum tointermediate gun-target ranges, is th eballistic mode. The projectile flies on a purelyballistic trajectory similar to that of aconventional artillery round until it reaches apoint on the descending branch of itstrajectory. At that point, the laser designatoroperator is cued to begin designating thetarget. The Copperhead projectile acquiresthe reflected laser energy and initiates theinternal guidance and control that allow it tomaneuver to and hit the designated target. Inthe intermediate to maximum ranges, theCopperhead projectile flies in the glide mode.In the glide mode, the round flies on a ballistictrajectory to a point just beyond th emaximum ordinate. The projectile, using itsinternal gyro as an inertial reference,maintains a constant flyout angle (356 or 444

mils). This isthe angle of fall. The projectile

maintains this angle of fall until impact. Thismode allows the projectile to fly under lowcloud cover and to fly out to extended rangesnot achievable in the ballistic mode.

c. The ground surface area in which theround can maneuver is limited. The optimumlimit of maneuverability of the Copperheadround is called a footprint. The size of thefootprint is determined with respect to theballistic aimpoint. This aimpoint is the pointon the ground where the Copperhead round

would impact if it did not maneuver. Theballistic aimpoint is on the gun-target line,usually short of the target location sent in bythe observer. The distance that the ballisticaimpoint is short of the target location variesand is called the offset correction. This offsetdistance is used to ensure that the maximumprobability of hit occurs at the original targetlocation sent in by the observer. The largerthe target location error, the lower theprobability of hitting the target (fig 9-47).

Figure 9-47. Copperhead footprint and offsetcorrection.

9-53

NOSE CONE

NOSE CONE

NO

WINDOW



FM 6-40

d. Copperhead missions, like conven-tional missions, can be fired on eitherplanned targets or targets of opportunity.

(1) Planned targets. Firing onplanned targets (fig 9-48) achieves fasterresponse

times. Planned targets fall into tw ocategories.

(a) Priority targets. For prioritytargets, data are precomputed and set on theguns. The Copperhead round is prepared andplaced in or near the howitzer. Unlessotherwise specified on the target list, twoCopperhead rounds are prepared in advancefor each Copperhead priority target.

(b) On-call targets. On-call targetsfor Copperhead are handled in the samemanner as those for conventional

missions.Firing data will be held at the FIST and sentto TACFIRE/BCS for processing as prioritytargets or targets of oportunity.

(2) Targets of opportunity. ACopperhead target of opportunity isprocessed in nearly the same manner as atarget of opportunity for conventionalmunitions. Since the FDC cannot begin tocompute firing data until the call for fire isreceived, this method of engaging a targetwith Copperhead has a slower response timethan that for planned

targets.

9-36. COMPUTATIONS FORSHELL COPPERHEAD

a. Firing data for Copperhead targets canbe computed manually, with the BCS, or withFADAC.

b. When a Copperhead target list isreceived (voice) from the battalion FDC,priority targets are processed first. Firingdata are sent to the guns assigned to eachpriority target (normally one platoon pertarget) and recorded in the battery FDC. Theguns prepare rounds and lay on these databetween other missions until otherwisedirected by the FDC. Firing data for the restof the Copperhead target list are thencomputed and recorded, by target number, inthe fire direction

center.e. The target locations for all planned

Copperhead targets are stored in FADAC orin the battery computer system. AllCopperhead firing data are updated (prioritytargets first) as changes in weather and otherfactors occur. Battery FDCs should knowhow to use the Copperhead footprint templateand should know about the 800-mil angle Trequirement.

d. Thebattery is

Response

observer must know when theprepared to fire on his targets.time will be excessive if the

TARGETNO

462/

A6,zW.5/

4 8 ,aqa,

A8 4W.4

AAww

TARGETLOCATION

3S 78 ,o t4

36/7 4%4&a

372z8"/olr3790o qoqql

38 o& qI$1

380.A4/75m3 L ¥/ m

44,Uz1 44IIAL 0 5

OBSERVER

rle7-18

IL57

PRIORITY(v -YES)

V,

FIRED(%,,-YES)

PLATOONSTO FIRE

c

I-

NO OF ROUNDSPLANNED

3

CHG

5a

I m e - - ____

TRAJECTORY

k A ..

SWITCHSETTING DEFLECTION

/Iist

MI.SS

SR i95GI54 dMC &'~Q36k4 /44.

Se

L

LJ

2..2

4 4 a

~ 6 1 2 7

1siiIE

SAL

.36411

3217I 2 ~ i L

IS49,..j

qETOF

i

A5

qj Ljq

5s 14 zu

DESIGNATETIME

41

45

5

/

/9

.24,501

Figure 9-48. Sample Copperhead planned target chart.

Big

j9-54

caairs ilo 4'i

rm--.

M

WJPXA)

X41 3.27Y.



FM 6-40

Copperhead rounds and the guns are notprepared in advance. The FDC transmits themessage to observer and the ready messageto tell the observer that the unit is prepared tofire on the priority target at any timethereafter. If target priorities change duringthe battle, the firing unit must change thedata on the guns and the rounds quickly toprovide continued support. If the mission isprocessed through TACFIRE, the batteryFDC does not need to send an MTO.

9-37. MISSION PRIORITY

Copperhead missions take priority overconventional missions unless the tacticalsituation or commander's guidance dictatesotherwise. A firing unit may have both aplanned priority Copperhead mission and anFPF mission. The firing platoon identified forthe Copperhead mission is laid on theCopperhead data, while the rest of the batteryis laid on FPF data. Once the attacking forcespass the Copperhead mission location or ge tclose to friendly defensive positions (within1,000 to 1,500 meters of FPF data or knownobserver locations), the FDC shouldautomatically have the entire battery lay onassigned FPF data between fire missions.Normally, the Copperhead target will nothave higher priority than the FPF once the

enemy is within 1,000 to 1,500 meters.Therefore, it is important for the FDC to keepaccurately abreast of the overall tacticalsituation at all times.INote.emember, the maneuver com-ander's guidance may override he generalrules in this publication.

rules in hrigi i i

9-38. COPPERHEAD SOP

Unit SOPs dealing with Copperheadmissions are helpful in rapidly disseminatingmission-essential information with aminimum of discussion. When used withextensive training, good unit SOPs can resultin more streamlined fire missions.

9-39. VOICE CALLSFOR FIRE

a. An observer requesting Copperheadfires will send a call for fire to the battery

FDC over an established fire'net. Calls for fireare sent to request fires on both plannedtargets and targets of opportunity.

b. A voice call for fire for planned targetscontains the following elements:

ELEMENTObserveridentificationWarning order

Targetdescription

Method ofengagement

Method of control

EXAMPLE

THIS IS Y4A71

FIRE TARGETAY4781, OVER

FOUR TANKS

5 ROUNDS

AT MY

COMMAND,OVER

(1) If the number of rounds to fire is notspecified in the call for fire, the FDC will firethe number of rounds specified for that targeton the Copperhead target list. If the numberof rounds is not specified-on the target list, theFDC will fire two rounds at the target.

(2) When the observer requests AT MYCOMMAND, the Copperhead rounds will befired at intervals of at least 20 seconds afterthe observer gives the command to fire. The

exact interval is established by the FDO inhis fire order or by unit SOP. When BYROUND AT MY COMMAND is requested,the observer will control the firing of eachCopperhead round.

(3) To enhance mission responsivenesswhen engaging priority targets, the observermay omit the target description, method ofengagement, and method of control.

c. The FDC will fire the Copperheadrounds at intervals of at least 20 seconds after

firing the first round.d. Calls for fire for targets of opportunity

follow the same format as the standard callfor fire.

ELEMENTObserveridentificationWarning order

EXAMPLEY5A57, THIS ISY4A71

FIRE FOREFFECT,POLAR, VER

9-55



DIRECTION1800, DISTANCE3450, VERTICALANGLE +5, OVERTWO TANKS

COPPERHEAD,3 ROUNDS

BY ROUND, ATMY COMMAND,OVER

9-40. MESSAGE TOOBSERVER(AUTONOMOUS)

a. After a call for fire has been receivedand mission processing has started, an MTO

is sent as soon as possible before firing.b. The MTO for Copperhead missions

includes the following elements:

ELEMENT

Unit firing

Number of rounds

Laser pulse repeti-tion frequency codeTime of flight

EXAMPLEA3Q27

3 ROUNDS

CODE 241TIME OFFLIGHT

c. If the battalion FDC is in tacticalcontrol, it will send the MTO for plannedtargets.

9-41. LASER PULSEREPETITIONFREQUENCY CODE

For a Copperhead mission to be successful,the three-digit PRF code set on theCopperhead round must match the PRF codeset on the observer's G/VLLD. The FDCs aregiven a list

of all observer PRF codes by callsign. One PRF code is indicated as primaryfor each observer. The FDC selects the properPRF code on the basis of the observer'sidentification in the call for fire and sends itto the guns, where it is placed on theCopperhead round. If the FDC sends theobserver a different code in the MTO than theone set on the G/VLLD, the observer willchange the PRF code on his G/VLLD tomatch the code sent by the fire directioncenter.

Location of target

Target description

9-56

FM 6-40

Methodment

of engage-

Method of control

9-42. FIRE ORDERa. The elements set to standard are not

addressed unless a change to the standard isdesired.

b. Normally, a single platoon will handlea given Copperhead fire mission. If thetactical situation permits, the FDO, in his fireorder, may specify more than one platoon tofire a Copperhead mission to facilitate attackof the target.

9-43. COMPUTATION OFFIRING DATA

a. Initial Chart Data. The computa-tion of firing data for Copperhead begins

with determining chart data. This applies toboth planned targets (target locations aretaken from the Copperhead target list) andtargets of opportunity (target locations areprovided in the call for fire). The initial chartdata required for Copperhead missions arechart range, chart deflection, and angle T.Normally, chart data are determined by theHCO in a manual fire direction center and bythe VCO in a manual/FADAC fire directioncenter.

b. Charge and Trajectory Selection.Given the chart range to the target, the FDOor chief computer enters the Copperheadcharge selection table (table 9-30) in theCopperhead TFT (FT 155-AS-0) under theappropriate weapon system. The charge andtrajectory to fire are determined byidentifying the range interval for a listedcharge that includes the chart range. Forexample, the charge for chart range 5630 ischarge 5GB. The ballistic mode trajectory isselected. If the chart range falls exactly onthe range changeover point for two charges,the lower charge and correspondingtrajectory are selected. The selected charge isthen announced to the computer.

Notes . 1. Copperhead trajectories areexplained later in this section.

2. It is important that the range intervalsfor each listed charge be strictly adhered to,since firing outside these intervals mays ign i f ican t ly degrade Coppe rhead ' sperformance.

0



FM 6-40

Table 9-30. Copperhead charge selection.

TARGETCLOUD HEIGHT FOOTPRINT

RANGE (KM) MODE CHARGE MINIMUMS CODE

FROM TO M3A1 M4A2 M119A1

Low-Angle M109A1 and M 109A1 B Howitzers:

3.0 4.6 ballistic ) 4 10% of range A

4.6 5.8 ballistic 5 10% of range B5.8 7.2 ballistic (6) 1 0% o f ra n ge C7.2 8.8 ballistic (2) 1 0% o f ra n ge D

8.8 9.5 glide (356 mils) 750 meters E

9.5 11.6 glide (356 mils)U 600 meters F blue750 meters H green

11.6 13.0 glide (444 mils) 900 meters G

Low-Angle M109A2, M109A3, and M198 Howitzers:

3.0 4.6 ballistic 4 10% of range A4.6 5.8 ballistic ( 5 10% of range B

5.8 7.2 ballisticG 10% of range C

7.2 8.8 ballistic (2) 10% of range D

8.8 9.5 glide (356 mils) (9) 750 meters E9.5 11.0 glide (356 mils) 0 600 meters F11.0 13.2 glide (356 mils) (B 600 meters H blue

750 meters H green

13.2 16.8 glide (444 mils) 0) 900 meters J

High Angle-All Weapon Systems:

5.0 6.5 ballistic (5 5 2,120 meters K

6.5 8.0 ballistic () 2,120 meters L

8.0 9.5 ballistic 0 2,120 meters 1 M

9.5 11.6 ballistic 0 2,120 meters N

IM109A2, M109A3, and M198 howitzers only.

0 Preferred charge.

9-44. ANGLE T AND TA R G E T round's ability to successfully acquire and

CLOUD HEIGHT CHECK engage its intended target.

a. The angle T check, by either the FDO or b. The target cloud height check is made

the chief computer, is made by listening to the by computing the target cloud height,

announced angle T and determining whether expressing it to the nearest 50 meters, and

it meets the angle T requirement for comparing it with the minimum cloud heightCopperhead (800 mils or less). Copperhead requirement for the charge selected. The

should not be fired when the angle T is target cloud height can be computed in one of

greater than 800 mils. An angle T of this two ways, depending on the method used to

magni tude may seriously degrade the locate the target.

9-57



FM 6-40

(1) If the target is located by gridcoordinates, the observer altitude is added tothe observer cloud height to obtain the cloudaltitude. The target altitude (taken from amap) is then subtracted from the cloud

altitude to determine the target cloud height.

EXAMPLE:Observer cloud heigt 740 metersObserver alt + 460 metersCloud alt - 1,200 metersTarget alt - 355 metersTarget cloud height = 845 meters

, 850 meters

(2) If the target is located by laser polarplot, as will normally be the case of targets ofopportunity, compute the target cloud heightas follows: First, using the OT distance andvertical angle reported by the observer,compute the observer-target vertical interval(OT VI) by use of the C- and D-scales of thegraphical site table. Then add OT VI to theobserver altitude to determine the targetaltitude. Compute the cloud altitude byadding the observer altitude to the observercloud height. Determine target cloud height

by subtracting the target altitude from thecloud altitude.

EXAMPLE:OT distance

Vertical angle

OT VI

Observer altObserver cloud height

340 meters-32

-105 (fromGST)

460 meters740 meters

*Target alt observer alt + OTVI=460 + -105)= 355Cloud alt = observer cloud height +observeralt = 740 + 460 = 1200Target cloud height = cloud alt - target alt =1200-355=845 85 0

Notes. 1. In a manual FDC, the VCOnormally computes the target cloud height-and reports it to the FDO or chief computer.

The FDO/chief computer then checks theminimum target cloud height requirement.,In a manual/FADAC fire direction center,the FDO/chief computer normally performsall functions associated with the target cloud

height check when data are computedmanually. When data are computed withFADAC/BCS, the computer automaticallychecks the target cloud height.2. An OT VI of less than ±30 meters can beignored for targets of opportunity. In suchcases, target cloud height equals observercloud height.

3. When the target cloud height is below theminimum required for the selected charge,Copperhead rounds should not be fired.Insufficient target cloud height willadversely affect the accuracy of Copperheadrounds.

9-45. DETERMI[NATION OFTHE RANGE OFFSETCORRECTION

a. To facilitate Copperhead's ability tohome in on the target, the computer applies arange offset correction to the chart range(tables 9-31 and 9-32). He obtains the rangeoffset correction by entering the range offsettable in the Copperhead TFT for the mode tobe fired with chart range expressed to thenearest 100 meters.

Table 9-31. Range offset-ballisticmode (low angle).

RANGE OFFSETCHART RANGE CORRECTION

(METERS) (METERS)

3,000 03,100 -503,200 -1003,300 -1503,400 -2003,500 -2503,600 -3003,700 -3503,800 -4003,900 -4504,000 and beyond -500

Range offset correction = -500

9-58



FM 6-40

Table 9-32. Range offset-glide mode.

CHART RANGE RANGE OFFSETMODE (METERS) CORRECTION (METERS)

Glide-356 Mils' 6 000 and above 0

Glide-444 Mils 2 6,000 and above -300

'Do not fire with cloud ceiling below 600 meters

EDo not fire with cloud ceiling below 900 meters.

b. When the computer applies the range to determine firing data from the Copperhead

offset correction to the chart range, the result graphical firing tables and site from the

is the offset chart range. Copperhead graphical site table.

EXAMPLE:

Chart range 5,630 meters 9-46. TRAJECTORIESRange offsetcorrection (+) -500 meters a. Low-Angle Ballistic Mode. The

Offset chart pr imary mode for the minimum to

range 5,130 meters intermediate gun-target ranges is th e

low-angle ballistic mode (fig 9-49). Theprojectile travels in a purely ballistic

c. The offset chart range serves as the trajectory similar to that of a conventional

entry argument for table F of the Copperhead artillery round until it reaches a point on the

tabular firing table. It is also the range used descending branch of its trajectory. At that

BALLISTICMODE

D

CLOUD .. ..

TARGET

BALLISTIC

AIMING POINT

START 200 GLIDE (356 MILS)

CLOUD ::

GLIDE MODE HEIGHT

0 TARGET

D =MINIMUM DISTANCE COPPERHEAD (Not to scale)

ROUND MUST SEE REFLECTED LASERPULSES.

Figure 9-49. Comparison of low-angle ballistic and glide mode trajectories.

9-59



FM 6-40

point, the observer has begun designating thetarget with the G/VLLD. The Copperheadprojectile acquires the reflected laser energyand initiates internal guidance and controlthat allow it to maneuver to the target.

b. Glide Mode. Fromthe intermediateto maximum ranges, the Copperhead

projectile travels in the glide mode (fig 9-49).In the glide mode, the projectile travels in aballistic trajectory to a point just beyond themaximum ordinate. Here the projectile, usingits internal gyro as an inertial reference,maintains a constant angle of fall (356 or 444mils). The projectile maintains this angle offall until laser acquisition. The glide modeallows the projectile to fly out to extendedranges not achieved in the low-angle ballisticmode.

c. Fi r ing Tables. Tabular an dgraphical firing tables have been produced tohelp the computer manually determine firingdata for the different Copperheadtrajectories. The GFTs are based on the rangeintervals outlined in the charge selectiontable.

d. High-Angle Fire. Firing Copper-head high angle will be discussed later in thischapter.

Note. The examples of the TFT, GFT,andGST from this point on may show different

values than the actual ielded TFT, GFT, andGST. The examples used in this section areintended to stress format and proceduresonly.

9-47. DESCRIPTION OF M712LOW-ANGLE BALLISTICGFT

a. The basic design of the Copperheadlow-angle ballistic GFT (fig 9-50) is similarto that of low-angle GFTs for conventionalmunitions. The scales appearing on the rulefrom top to bottom are as follows:

(1) Range scale. The range scale is thebase scale. Range is expressed logarithmi-cally, in meters, and varies for each charge. Itincreases from left to right and is read to thenearest 10 meters.

(2) Elevation scale. The elevationscale increases from left to right and isgraduated in mils. It is read to the nearest mil.

(3) Time- se t t i ng scale . Thetime-setting scale provides the first twodigits of the five-digit switch setting sent tothe guns. The last three digits are the PRFcode. If a reading falls exactly on thechangeover point

between two time settings,the higher time setting will be used.(4) Designate time scale. The FD C

sends DESIGNATE to the G/VLLDoperator approximately 20 seconds beforeimpact. The operator must designate thetarget during the last 13 seconds of time offlight. The designate time scale indicates themaximum time the FDC can wait after theround is fired to send DESIGNATE and stillallow the G/VLLD operator to designate thetarget. If a reading falls exactly on thechangeover point

between two designatetimes, the lower value will be used.(5) Time-of-flight scale. The time-of-flight scale indicates the time to impact

after the Copperhead round is fired. It isgraduated in tenths of a second and is read tothe nearest whole second.

b. Some Copperhead GFT settings reflectextremely large total range corrections. Tofacilitate applying these settings to the GET,he Copperhead low-angle ballistic cursorwas produced without a manufacturer'shairline. A range gage line is drawn parallelto the RG K line at any convenient location onthe cursor to read data from the low-angleballistic GFT. All data are read from theconstructed elevation gage line.

9-48. LOW-ANGLE BALLISTICGFT SETTING

a. Registrations are not fired with theCopperhead round. Also, ballistic differencesbetween HE and Copperhead will not permitthe use of HE low-angle GFT settings withCopperhead. Therefore, Copperheadlow-angle ballistic GFT settings are basedonly on met, propellant temperature, andmuzzle velocity corrections. They arebtained through FADAC/BCS (preferred)or by use of subsequent met procedures tomanually solve a met. When manuallysolving a met for Copperhead, apply thefollowing guidelines:

(1) Use a position deflection correctionof 0.

9-60



FM 6-40

HfOW 55 mraSoft UftP" AS.OM112CLGP

SOD sit "MeCHARGE 5GP Pie Woo "m BALLISTIC MODE

l ap oft o-mom'Of"NPROVISIONAL

.... ; ... ......... ,f,

ic &0•JZ : SM U

Fiur 950pprhadlo-agl b l l s o FTe

(2) Use muzzle velocity variation(MVV) calibration data determined from theM90 velocimeter as the position velocityerror.

Note. An MVV for Copperhead deter-mined by calibration may not be available.When tube wear data become available forCopperhead, the loss in muzzle velocity dueto tube erosion as determined from a recentpullover gage reading or rom equivalent ullcharge rounds will be used as the positionvelocity error. A position velocity error of 0will be used in the absence of calibrationdata or Copperhead. Manually derived GFTsettings apply to the ballistic mode only.Examples are in the TFT.

(3) Total fuze setting corrections are notcomputed.

b. If time permits, multiplot GFT settingsshould be computed for the low-angleballistic GFT. This is especially importantwhen working with charges 6WB and 7WB.The ranges used to compute the multiplotGFT settings should come from the upper,middle, and lower thirds of the range intervalfor the charge. Use met check gage-points ifthey are available.

9-61



FM 6-40

Table 9-33. Preferred ranges for one-plot Copperhead GFT settingsin the low-angle ballistic mode.

OFFSET CHART CORRESPONDINGRANGE CHART RANGECHARGE (METERS) (METERS)

4GB or 4WB 3,550 4,0505GB or 5WB 4,700 5,2006WB 6,000 6,5007WB 7,500 8,000

c. When time does not permit thecomputation of multiplot GFT settings, one-plot GFT settings should be computed. One-plot GFT settings provide acceptableaccuracy for the computation

of firing data.The degree of accuracy for one-plot GFTsettings is higher for charges 4GB/WB and5GB/WB than for charges 6WB, 7WB, and 8.The ranges at which one-plot GFT settingsshould be computed are shown in table 9-33.

Note. When GFT settings are determinedby manually solving a met, the range usedmust be converted to an offset chart range.When FADAC/BCS is used to derive GFTsettings, the uncorrected chart range isentered. FADAC/BCS automatical ly

applies the range offset correction. Thederived GFT setting is then applied on theGFT at the offset chart range. In all cases,the range listed in the GFT setting is theoffset chart range.

d. A low-angle ballistic GFT settingcontains the following information:

(1) Unit.(2) Charge.(3) Trajectory (for example, low-angle

ballistic [LA bal]).(4) Ammunition lot.(5) Range (offset chart range).(6) Elevation.(7) GFT deflection correction.

EXAMPLE:GFT A: Chg 5, LA Bal, Lot RY, Rg 4700, El357; GFT Df Corr: R3.

9-49. TRANSFER L]MITSA Copperhead low-angle ballistic GFT

setting is valid for the range interval

specified for the charge in the chargeselection table. The GFT setting is also valid400 mils left and right of the azimuth of firefor which it was computed. Accuracy of thefiring data will, however, degrade rapidly asthe transfer limits are approached.

9-50. APPLICATION OF THEGFT SETTING

The procedures for applying the GFTsetting to the GFT are explained below. Usethe following low-angle ballistic GFTsetting:

GET B: Chg 5, LA Bal, Lot RY, Rg 4700,El 361; GFT Df Corr: L2.

STEP 1. Place the constructed range gageline over range 4700 on the rangescale.

STEP 2. Place a pencil mark on elevation361 on the elevation scale.

STEP 3. Slide the cursor so that the pencilmark is over the RG K line.

STEP 4. Construct the elevation gage lineby drawing a line through thepencil mark parallel to the RG Kline.

STEP 5. Place the constructed range gageline over range 4700 to verify thatelevation 361 is read under theelevation gage line.

STEP 6. Enter the GFT deflectioncorrection on the upper right-hand corner of the cursor.

9-62

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FM 6-40

Note. The location of the range gage linemay have to be adjusted to accommodateplacement of the elevation gage line.

9-51. DATA READ FROM THELOW-ANGLE BALLISTICGFT

To read data from the low-angle ballisticGFT with a GFT setting applied (fig 9-51),place the range gage line over the offset chartrange. Read elevation, time setting,designate time, and time of flight under theelevation gage line.

EXAMPLE:Offset cha r t range 5110

Elevation 413

Time setting 12

Designate time 6

Time of flight 23

Figure 9-51. M712 low-angle ballistic GFT with GFT setting applied.

9-63



FM 6-40

9-52. M712 LOW-ANGLEGLIDE MODE GFT

a. The Copperhead glide mode GFT (fig9-52) allows the FDC to compute data forCopperhead in the glide mode. Because of thelimited accuracy of the manual solution,firing data computed by FADAC or BCSshould be used whenever possible.

b. The organization of the Copperheadglide mode GFT differs from that of theballistic mode GFT. At the top of a glide modeGFT is a common range scale. Beneath therange scale are time-setting groups. Eachgroup has its own elevation, time-of-flight,and designate time scales. The time-settinggroups are color-coded alternately red andblue to help identify the scales belonging toeach

group.c. Charges 7WB and 8 have glide mode

GFTs for the 356-mil (20) and 444-mil (250)glide angles. Charge 6WB has a glide modeGFT for the 356-mil (20) glide angle only.

d. As with the low-angle ballistic GFT,there is no MHL on the cursor. A range gageline has been drawn parallel to the RG K lineat a convenient location on the cursor. Thiswas done to facilitate applying GFT settingswith extremely large total range corrections.

9-53. DETERMIENATION OFTHE TIME SETTING

The clear area within each time-settinggroup is used in conjunction with theconstructed range gage line to determine thetime setting to be fired. This is done byplacing the range gage line over the offsetchart range (fig 9-52). The clear areaintersected by the range gage line determinesthe time setting

and time-setting group to beused in computing firing data. If the rangegage line lies exactly between the clear areasof two time-setting groups, the numericallyhigher time setting and time-setting groupwill be used.

Figure 9-52. M712 low-angle glide mode GFT.

9-64

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FM 6-40

9-54. DETERMINATION OFELEVATION, TIME OFFLIGHT, ANDDESIGNATE TIME

Elevation, time of flight, and designatetime are all read under the elevation gage linefor the selected time-setting group.

Note. Under uncertain conditions, the

FADA C may compute glide mode firing datathat differ from the manual solution firingdata. In these cases, the computer solutionshould always be used. Compute r-determined firing data (FADA C or BCS)should always be used when actuallyfiring Copperhead in the glide mode

during t raining.

9-55. GLIDE MODETRANSFER LIMITS

The Copperhead glide mode GFT setting isvalid for the range interval specified for thecharge and glide angle in the charge selectiontable. Deflection transfer limits are 200 milsleft and right of the azimuth of fire for whichthe GFT setting was computed. Accuracy ofthe firing data degrades rapidly as the

transfer limits are approached.

9-56. GLIDE MODE GFTSETTING

a. Graphical firing table settings must beapplied before firing data are extracted from

the Copperhead glide mode graphical firingtable. The Copperhead glide mode GFT is

never used without a GFTsetting. Glide mode

GFT settings are always derived fromFADAC or other computer systems such as

the BCS or TACFIRE. Glide mode GFT

settings cannot be obtainedby manually

solving a met or with a programable hand-held calculator, since these methods arebased on purely ballistic trajectories only.

b. One-plot GFT settings are computedfor glide mode graphical firing tables. Theranges at which FADAC or BCS GFTsettings for Copperhead glide mode GFTs arecomputed are listed in table 9-34 for thecharges and glide angles.

Notes. 1. The glide mode offset rangecorrection for all 356-mil glide angles is 0.The offset range correction for all 444-milglide angles is -300 meters.

2. The chart ranges listed in table 9-34 are

converted to offset chart ranges before the

derived GFT setting is applied to the GFT.

c. A glide mode GFT setting contains thefollowing information:

(1) Unit.(2) Charge.

(3) Glide angle trajectory (for example,356 mils glide).

(4) Ammunition lot.

(5) Range (offset chart).

Table 9-34. Ranges for GFT settings.

GLIDE ANGLE 356 MILS GLIDE ANGLE 444 MILS

CHARGE WEAPON CHART RANGE (METERS) CHART RANGE (METERS)

6WB All 9,150 NA

7WB M109A1 10,500 12,300

M109A11B

7WB M109A2 10,250 NAM109A3M198

8 M109A2 12,100 15,000

M109A3M198

9-65



FM 6-40

(6) Time-setting group.(7) Elevation.(8) GFT deflection correction.

EXAMPLE:GFT C: Chg 7, 356 Mils Glide, Lot RT, Rg10,500, Time-Setting Group 52, El 512; GFTDf Corr: R5.

d. Using the example glide mode GFTsetting shown above, apply the GFT settingto the glide mode GFT as outlined in figure9-53.

STEP 1. Place the constructed range gageline over range 10,500 on therange scale.

STEP 2. Place a pencil mark at elevation512 on the elevation scale of time-setting group 52.

STEP 3. Move the cursor so that the pencilmark is over the RG K line.

STEP 4. Construct the elevation gage lineby drawing a line through thepencil mark parallel to the RG Kline.

STEP 5. Place the constructed range gageline over range 10,500, and verifythat elevation 512 is read under

the elevation gage line in time-setting group 52.STEP 6. Enter the GFT deflection cor-

rection on the upper right-handcorner of the cursor.

Figure 9-53. M712 glide mode GFT with GFT setting applied.

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FM 6-40

9-57. SWITCH SETTING

The Copperhead switch setting consists offive numbers (fig 9-54). The first two numbersare the time setting determined by the firedirection center. The last three numbers arethe PRF code of the G/VLLD operator. Thiscombination setting establishes a commonlaser frequency between the round and theG/VLLD.

9-58. COMPUTATION OF SITE

a. The VCO computes site for Copper-head by use of the Copperhead GST (fig 9-55). Three separate range scale slides havebeen produced to accommodate all modes andcharges.

b. The Copperhead GST and the GST forconventional munitions are used in nearlythe same manner. The difference is that theoffset chart range is used instead of chartrange on both the ballistic and the glide modeGSTs and the appropriate time-setting groupmust be used on the glide mode GST. Figure 9-54. Explanation of the switch setting.

Figure 9-55. Copperhead graphical site table.

9-67



FM 6-40

9-59. COMPUTATIONOF DEFLECTIONCORRECTION

There is no drift correction for theCopperhead round. Therefore, the total

deflection correction is equal to the GFTdeflection correction and is appliedthroughout that charge and mode withoutmodification.

9-60. COMPUTATION OFFADAC DATA

The FADAC must be programed withRevision 6A before it can compute firing datafor Copperhead. Information concerningFADAC Revision

6A will be publishedseparately.

9-61. LIMITS OF THEBATTERY CENTERSOLUTION

a. Manual firing data for Copperhead areinitially computed from battery center. If thecenter of the gun platoon firing theCopperhead mission is located within 100meters of

battery center, the gun platoon canuse the firing data computed at batterycenter. If the platoon center is located fartherthan 100 meters from battery center,deflection and elevation corrections for theplatoon should be computed and applied tothe battery center solution. The proceduresfor computing these corrections are inchapter 13. Corrections are made to thebattery center solution burst point.

b. When time for data computation islimited, as is normally the case for targets ofopportunity, and the platoon center is located

farther than 100 meters from battery center,the FDC should compute at least a deflectioncorrection. Because of the egg shape of aCopperhead footprint, the Copperhead roundcan compensate for errors in range easierthan it can for errors in deflection.

c. When computing data with FADAC,the platoon centers should be stored asbattery locations if they are 100 meters or

farther from battery center. Data for theplatoons can then be computed by using themass fire function.

d. The BCS computes separate firing datafor each gun. Procedures to modify a batterycenter solution do not apply

to the batterycomputer system.

9-62. TARGET ATTACKCONTINGENCIES

a. If a target cannot be attacked byCopperhead because of insufficient targetcloud height, the FDC must inform theobserver. Coordination to fire other types ofmunitions on the target can then be madebetween the observer and the FDC.

b. If a target cannot be attacked byCopperhead because of the angle T (greaterthan 800 mils), the battery FDC shouldcontact the battalion FDC to see if themission can be taken by another batteryhaving an angle T of 800 mils or less. Ifanother battery is available, the originalbattery FDC tells the observer to contact theFDC of the battery taking the mission. If noother batteries are available, coordination tofire other types of munitions on the target canbe made between the observer and the FDC.

9-63. RECORD OF FIREa. Records of fire for Copperhead

missions are completed in nearly the samemanner as those for conventional firemissions. The offset chart range is entered inthe range (Rg) block with the notation "offsetchart." The switch setting is entered in thefuze setting (Ti) block with the notation "swsetting." Designate time is written under thetime of flight (TF) block.

b. Normally, firing data for plannedtargets can be computed by use of aCopperhead planned target list work sheet orboard. The record of fire can then be used torecord the actual firing of the data. Figures9-56 and 9-57 show how records of fire arecompleted for various situations. The GFTsetting is as follows:

OFT B: Chg 5, LA Bal, Lot RY, Rg 4700,El 356; OFT Df Corr: R3

9-68



FM 6-40

RECORD Of FIRE

CALLFORFilC 4AR RG. 5740 An

.4 i11+1@ 10.1/10D MOS o

FEoRER LFT PLT7.yP IEC E- ,B)O R A M TCCHG O5FFSET.

CLOU C S Q 72$? COMMANff r a5

u.. ,f,. II, o Fig.ure 9-56 . or o ietr of ,-ppo runity . ,. I. .CALFFOR zN-2r

oberer 7- F/FEIS $FL.~ . .. ......2.'

Grid: F/it

Pohr:Dir Di U/O VA 20IR

"kr Dir .UD-

C a'4s RW119mc s 10losSi NOlCar

FiRl ORDER FT ItT ~1PEC±Z BY R ) M C CIT SEOf C S T OfCafRt si +

INITIALIRECOMMANDS ViM MF R PTCT g - bt Of3El

.......-

plnstr 3/ AIKr B I MC S1CPf, Lot Chg 5f t

SP ,ff "" y coE~,1By, , 7....

THEPRPOENTAGNC ISTRDO

CTot4cF4igurerioOi-FiringRecord QUoFfi ll.C A

FigureC -57. Recoo r Of Fire--on-al Cart

9-69



FM 6-40

9-64. FIRE COMMANDSa. The order in which initial and

subsequent fire commands are given is thesame as that for conventional fire missions,except that uze is omitted and switch setting

is sent instead of time. Figure 9-58. is anexample of fire commands.

b. BY PIECE, BY ROUND, AT MYCOMMAND is sent to the guns for allCopperhead missions, regardless of themethod of control specified by the observer.For each round, the FDC gives the commandto fire to the howitzers firing the mission afterthe observer has given the command FIRE(when AT MY COMMAND or BY ROUND,AT MY COMMAND has been specified bythe observer).

EXAMPLE:The observer requested AT MY COM-MAND in his call for fire and has given thecommand to fire. The FDC initiates firing at20-second intervals.NUMBER 1 . . . FIRE (wait 20 sec);

NUMBER 2 FIRE (wait 20 sec);NUMBER 1... FIRE (wait 20 sec);NUMBER 2... FIRE.. . .

R2ECORZDFFIRlECALLM FIRE

Goorvor AF/FFI/IS/ Tt 100l

Pc ADi Cia U/D ,VA ./

SUN ftU/0D0/-4 Si ito 100gSi M013Corr

RECD0Df Corr Si

:.D.C flL/ACJD rp/z 2 Ul . 5 /sD

"P. .... 46Y... r.. . .... t A%-,oc"iACsLoCho';

Ta t LoctioMSUOSEOUEOJT FIRECOMMIANJDS

SbF1w n Crr hoFigurr9-8.i xamleffire comas.Cr P T p

[ ,, , o. ... ... . .'... . ... . ..... I.....

.. . . .. ... . . . . .. . . .... . .. "., +'.. . . .o~o.. I- . , . , , .,..,,.. o.... ... ..- .. . ... . . . ..

. FI Co. Cb , FI.C.rr.TiO. ( ).F.o.orr ).| ..y.

. .. ..... ..... .

Figure 9-58. Example of fire commands.

9-70



FM 6-40

Note. If one howitzer is firing two roundsand the other is firing one round, thehowitzer firing two rounds should be firedfirst to give it maximum time to load itssecond round. The FDC must closely monitor

the howitzer's report of READY for eachround. If the next gun to fire is not ready, thecommand to fire should be passed to the onethat is ready.

c. For priority missions, the FDC sendsfiring data to the guns in a do not load status.

9-65. ENGAGEMENTCOMMANDS

a. S h o t . As soon as the f i r s tCopperhead round is fired in a mission, theobserver receives SHOT from the firedirection center. If he specified AT MYCOMMAND or omitted the method ofcontrol in the call for fire, he receives SHOTonly once. The subsequent rounds are fired atintervals of at least 20 seconds withoutnotification. The exact interval will be set by

unit SOP. If the observer specified BYROUND AT MY COMMAND, he receivesSHOT for each round fired. If an observerfails to acknowledge SHOT for a givenround, it is not retransmitted, because theobserver's timing would be affected.

b. Designate (Voice).

(1) The next and most cri t icalengagement command is DESIGNATE.When the observer receives the commandDESIGNATE from the FDC, he begins

designatingthe target with the G/VLLD.

This command is sent at least 20 secondsbefore impact. If the time of flight is 20seconds or less, SHOT and DESIGNATEare sent in the same transmission.

(2) It is mandatory that the observerdesignate the target during the last 13seconds of time of flight. After the observerhas received SHOT, he should begin his owncountdown using the time of flight received inthe message to observer. If for some reason hehas not received a DESIGNATE message,

he should begin designation when 13 secondsare left in his countdown.

(3) If the battery is firing theCopperhead rounds automatically at20-second intervals, the command

DESIGNATEis sent only for the first round

fired. The observer continues designating forthe subsequent rounds while moving thelaser spot to the next target.

(4) If SHOT is given for each round or ifthe firing interval is greater than 20 seconds,DESIGNATE is given for each round

c. Designate Now (Voice). If anobserver fails to acknowledge th eDESIGNATE command, the commandDESIGNATE NOW is sent by the FDC untilthe observer acknowledges or the time offlight of the round has elapsed. If the observerfails to acknowledge the DESIGNATENOW command, SHOT and DESIGNATEare sent on the next round fired, regardless ofthe method of control. Time intervalsbetween transmission of this command maybe specified in unit SOP to allow the observertime to acknowledge.

d. R o unds Comple te . The FDCreports ROUNDS COMPLETE after theengagement command for the last round hasbeen sent and acknowledged. If the observer

wants to terminate firing before the lastround is fired and the FDC is controlling thefiring of subsequent rounds, he sendsCHECK FIRING, CANCEL CHECKFIRING, END OF MISSION. If theobserver is controlling the firing ofsubsequent rounds, he sends END OFMISSION to terminate the mission.

e. Requests for Additional Rounds. Ifadditional rounds are required to engage the

target array, the observer may request themby sending (so many) ROUNDS, REPEAT,

OVER after the last Copperhead round isfired.

9-66. HIGH-ANGLE FIRE

a. Introduction. The tactical situationmay dictate engaging ta rgets with

Copperhead by firing into or out of deepdefilade such as that found in heavily woodedor mountainous areas. When such is the case,

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FM 6-40

high-angle fire may be requested by theobserver or ordered by the FDO on the basisof the terrain in the target area or the batteryposition.

b. Restrictions. Because of the longtimes of flight involved, firing Copperheadhigh angle is not as responsive as firing it inone of the low-angle modes. Because of theserestrictions, Copperhead fired in thehigh-angle mode should be considered onlywhen a target cannot be engaged withCopperhead fired in a low-angle ballistic orglide mode. Restrictions on high-angle firewith Copperhead are as follows:

(1) The minimum range at whichhigh-angle firing data may be controlled is5,000 meters.

(2) The minimum cloud height requiredover the target is 2,120 meters.

(3) Charges 4GB and 4WB cannot beused to fire Copperhead high angle.

(4) High-angle fire for Copperhead isaccomplished in the ballistic mode only.

9-67. HIGH-ANGLE GFTThe high-angle GFT for Copperhead (fig

9-59) is similar in design to the high-angleGFT for shell HE (fig 9-60.). The differencesare as follows:

a. The Copperhead GFT has time-settingand designate time scales (both increase fromright to left).

b. The Copperhead GFT does not have100/R and drift scales.

c. The Copperhead GFT does not have anMHL on the cursor.

Figure 9-59. Copperhead high-angle GFT.

9-72

ortk*

0



FM 6-40

00E0 0 0 000500 0 00000 9000- 5000 51O0 00 5000 54000 5500 5 51 9000 59000 0L 6100 6000 000 50016500 6600 000

2 20 1210 120 0 0 20l60 0 01 ''600 60 '500 '1010 1N00000 so50

T. SET 22 21Is "•F5 ? 8 77 6 25,4-23

6 0101 50 49 40 47 46 45 44 43 42 41

12, 52 , 2,10 2 5O 1490 4180 t 10 160 1I, 0 t130 2o P 03 0100 o. 0010 2

Ifs.T.. ... . ... . .. ...... 25 4 S

5553 53 52 51 50 49 4os a? 046 05 4 4 0 4

o 0 0 0

Figure 9-60. High-angle GFT.

9-68. HIGH-ANGLE GFT

SETTINGS Note. When a high-angle GFTsetting is

a. As in the low-angle modes, a GFT computed by manually solving a met, the

setting should be applied to the high-angle offset chart range listed in table 9-35 for the

GFT. Since registrations are not fired with selected charge is used. If the FADAC/BCSis used to derive a high-angle GFT setting,

Copperhead, high-angle GFT settings are the corresponding chart range listed in theobtained through FADAC or by manual ly table for the selected charge is entered into

solving a met as descr ibed for the FADAC/BCS. FADAC/BCS automatically

Copperhead low-angle ballistic graphical applies the range offset correction. In all

firing table. cases, the GFT setting is applied on the GFT

at the offset chart range.b. -The ranges for which high-angle GFT

settings are computed are in table 9-35.

Table 9-35. High-angle GFT setting ranges.

OFFSET CHART CORRESPONDINGRANGE CHART RANGE

CHARGE (METERS) (METERS)

5GB or 5WB 5,200 5,750

6WB 6,770 7,250

7WB 8,360 8,750

8 10,270 10,550

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FM 6-40

c. The high-angle GFT setting containsthe following information:

(1) Unit.

(2)

(3)angle).

Charge.

Trajectory (for example, high

(4) Ammunition lot.(5) Range (offset chart range).

(6) Adjusted elevation.

(7) GFT deflection correction.

EXAMPLE:OFT B: Chg 5, High Angle, Lot RY, Rg 5200,El 1107; GFT Df Corr: L2.

d. The high-angle GFT setting is appliedon the GFT by first drawing a range gage lineperpendicular to the range scale through theGFT setting range. This gage line need notextend beyond the range scale. An elevationgage line is then drawn parallel to the rangegage line extending through the adjustedelevation on the elevation scale. The GFTdeflection correction is placed on the upperright-hand corner of the cursor. Except forthe range, all data pertaining to the GFT

setting charge should be read from theelevation gage line.

EXAMPLE:

Given: Offset chart range 5980 and GFTsetting in example above.

Elevation 960lO-mil site -10.7Time setting 21Designate time 25Time of flight 45

e. A Copperhead high-angle GFT settingis valid for the range interval of the selectedcharge when derived at the ranges specifiedin the example above. It is also valid only forthe charge and propellant type for which itwas computed and only within the deflectiontransfer limits established for conventionalmunitions.

, 9-69. DATA COMPUTATION

a. Before issuing a high-angle fire orderfor Copperhead, the FDO must ensure thatthe minimum range and target cloud heightrequirements are met.

b. The data for firing Copperhead in thehigh-angle mode are the same as those forfiring Copperhead in the low-angle mode.

c. The charge to fire is determined byselecting the preferred charge based on thechart range to the target. As a general rule,the lowest charge possible is selected. Specificguidelines for charge selection are outlined intable 9-36.

Table 9-36. High-angle charge selection.

RANGE PREFERRED(METERS) CHARGE

5,000 to 6,500 5GB6,500 to 8,000 6WB8,000 to 9,500 7WB9.500to 11,600 8

d. After the charge has been selected,enter the high-angle range offset table (fig9-61) with chart range (expressed to thenearest 100 meters), and extract the rangeoffset correction. Algebraically apply therange offset correction to the chart range. Theresult is the offset chart range. The offsetchart range is the range set off on the GFT todetermine firing data.

e. There are no drift corrections forCopperhead high-angle fire. Therefore, thetotal deflection correction is equal to the GFTdeflection correction.

Note. The high-angle range offsetcorrection table (fig 9-61) lists ranges in200-meter increments. If the chart range isexactly between the listed ranges, apply theoffset correction corresponding to the nextlower listed chart range.

9-74

S



RANGE OFFSET

BALLISTIC MODE - ANGLE*

RANGE OFFSET IN METERS

HEIGHT OF CLOUD CEILING

TARGET (METERS)RANGE

(METERS) MIN iioX

5000 -600 -600

5200 -590 -590

5400 -580 -5805600 -560 -5605800 -550 -550

6000 -540 -540

6200 -530 -5306400 -520 -520

6600 -510 -510

6800 -500 -500

7000 -490 -490

7200 -480 -4807400 -470 -470

7600 -450 -4507800 -440 -440

8000 -430 -430

8200 -420 -420

8400 -410 -4108600 -400 -4008800 -390 -390

9000 -380 -380

9200 -370 -3709400 -360 -3609600 -340 -3409800 -330 -330

10000 -320 -320

10200 -310 -31010400 -300 -30010600 -280 -280

10800 -270 -270

11000 -260 -260

11200 -250 -25011400 -240 -24011600 -230 -230

*USE ONLY FOR CLOUD CEILINGS ABOVE 2120 METERS ORABOVE THE MAXIMUMORDINATE IF THE MAXIMIUMORDINATEIS BELOW2120 METERS

...... . . . . . F igu re 9-61 L-Range offset, ballistic mode (high angle).

FM 6-40

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FM 6-40

f. Site for high-angle Copperheadmissions is ignored unless the angle of site,computed by use of the offset chart range, isgreater than ±30 mils. Site is computed in thesame manner as in conventional high-anglemissions.

9-70. EXAMPLE OF AHIGH-ANGLEMISSION

a. The FDO of Battery A has just receiveda Copperhead call for fire on three tanks in aravine. The following Copperheadhigh-angle GFT setting was derived by

FADAC for charge 5GB:GFT B: Chg 5, High Angle, Lot RY, Rg5200, El 1107; GFT Df Corr: L2

b. The following information wasprovided by the observer:Observer cloud greater than 2,120height metersObserver altitude 435

Observer-targetdirection 1730Observer-targetdistance 3370Vertical angle -11

c. After quickly ensuring that minimumrange and target cloud height requirementsare met, the FDO issues his fire order:RIGHT PLATOON, HIGH ANGLE, BYPIECE, BY ROUND, AT MY COM-MAND. The following chart information isobtained:

Chart range 5750Chart deflection 3079Angle T 450 right

Figure 9-62. Record of fire-Copperhead high-angle mission.

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FM 6-40

d. Noting that the chart range fallsbetween 5000 and 6500, the computer selectscharge 5GB.

e. With the chart range expressed to thenearest 200 meters (5,800 meters), the

computer enters the range offset table andextracts the range offset correction of -550.

f. The computer now computes the offsetchart range by adding the range offsetcorrection to the chart range: Offset chartrange (5200) = chart range (5750) + rangeoffset correction (-550).

g. The initial firing data are obtainedfrom the Copperhead high-angle GFT bysetting off the offset chart range under therange gage line.

Elevation10-mil siteTime settingDesignate timeTime of flight

1107-3.2222949

h. The computer requests and obtains anangle of site (+31) from the VCO.

i. Since the angle of site is greater than±30 mils, the FDO amends his fire order byannouncing INCLUDE SITE, and site iscomputed by the following method:

Site (-10) = 10-mil site factor (-3.2) x angle ofsite-10 (3.1).

j. The completed record of fire for thismission is shown in figure 9-62.

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FM 6-40

T he state of the atmosphere throughwhich a projectile passes is one of

the elements that affects a projectileafter it leaves the tube. The three

elements of the atmosphere that th ea r t i l l e ry cons iders in its gunne r ycomputations are wind (direction and

speed), air temperature, and air density.The met message conta ins ball is t icinformation about these atmosphericconditions.

Section I

PURPOSE AND USE OF MET MESSAGES

10-1. NONSTANDARDCONDITIONS

a. To place accurate fires on targets ofknown location without ad jus tment ,corrections must be applied to firing tabledata to compensate for the effects ofnonstandard conditions of weather, materiel,

and position. The most accurate way todetermine these corrections is to conduct aregistration. Normally, a registration todetermine current corrections is prohibited ornot feasible. In such a case, closelyapproximated corrections can be determinedby measuring deviations from standardconditions and computing corrections forthese deviations. The techniques used tomeasure deviations from standard and tocompute corrections for them are called metcorrections.

b. The firing tables used to produce firingdata for artillery cannons are based on anarbitrary set of standard conditions forweather, materiel, and position. To gain abetter understanding of the gunnery problemand artillery meteorological procedures, youmust know the standard conditions on whichthe firing tables and TACFIRE/BCS or

FADAC calculations are based. (Standardconditions are identified in figure 10-1).

c. Variations from these standards createnonstandard conditions that must becorrected for by either registration orcomputation. The manual computationsperformed in the FDC to compensate fornonstandard conditions are done on DAForm 4200. There are two met techniquesused-the concurrent met and the subsequentmet.

10-1



S'ARIDARDWEATHER

a Q- ApkiVVY tl YTIME.ALL SETTINGS AR EPERFECT.THE PROJECTILE AND

STANDARD FUZEMAT'ER]EL. ARE MANUFACTURED

PERFECTLY.THE PROPELLANTTEMPERATUREIS 700 F.THE MUZZLEVELOCITYISSTANDARD.THE TRUNNIONS ARELEVEL.

Figure 10-1. Standard conditions.

10-2. CONCURRENT METa. A concurrent met is solved to separate

the total corrections determined by aregistration into two parts. These parts aremet corrections, which are made to theelements that can be easily measured andcorrected, and position corrections, which aremade to the elements that cannot bemeasured. The total corrections for range,fuze setting, and deflection are caused by thetotal variations from standard conditions ofweather, materiel, and position existing atthe time of registration. Weather informationis provided to artillery units by artillery metsections in the format of a met message. Forthe concurrent met technique to be usedsuccessfully, it is important that theregistration be fired very close to the sametime that the met section is measuring theactual weather conditions.

b. If a registration is fired at the sametime the met section is measuring the existingweather conditions, it is possible to determinethe total corrections needed to compensate for

THE AIR TEMPERA-TURE IS 590 F.THE AIR DENSITY IS1225 g/m

3

AT SEA LEVEL.THERE IS NO WIND.

THE GUN AND TARGETARE AT THESAME ALTITUDE.THE RANGE IS ACCU-RATE.THERE IS NO ROTA-TIONOF THE EARTH.

THE GUN REACTS TOFIRING

v v n rfi; W v Ctim

10-2

FM 6-40

STAINADARDPOSMON

11 ---- - I nonstandard weather conditions. When theregistration is fired, the following variable,nonstandard conditions can be determined:

(1) The effects of wind, air temperature,and air density.

(2) The projectile weight and propellanttemperature of the lot fired.

(3) The difference in altitude betweenthe gun and the target.

(4) The drift at the registration pointrange.

(5) The effects of the earth's rotation onboth range and deflection.

c. The nonstandard conditions thatcannot be measured are called positioncorrections and are usually small, difficult tomeasure, and relatively constant. When allthe variable nonstandard conditions havebeen measured and the corrections computed,it is then possible to subtract the met(variable) corrections from the totalcorrections and determine the amount ofposition (constant) nonstandard conditions.

met corrections +(variable)

position corrections

(constant)total corrections =

d. The concurrent met technique startswith total range, total fuze, and totaldeflection correction from a registration. Thecorrections due to met are subtracted toisolate position corrections that areconsidered constant.

total corrections-

met corrections =

position corrections

10-3. oSUBSEQUENT METa. After a registration has been

conducted, the concurrent met has beensolved, and position constants have beenisolated, it will be unnecessary to registeragain from the same position. Met messagesreceived after the concurrent met are calledsubsequent mets. New total corrections and



FM 6-40

thus new GFT settings can be determined byuse of the subsequent met technique.

b. When a subsequent registration is notpossible, the subsequent met technique isused to produce a current GFT setting. A

subsequent met is solved by using DA Form4200. Other applications of the subsequentmet technique are eight-direction met, met toa target, and met to a met check gage point.

new met corrections +(new variables)

old position corrections =(constant)

new total corrections

10-4. VELOCITY ERROR

a. Ballistic variations from firing tablestandards that cannot be measured includemoisture content of the propellant, shellsurface finish, and survey or target-location

errors. Corrections for all unknownvariations are included in the totalcorrections determined for registration.Unknown variations affecting range aretotaled and are called position velocity errors.Position velocity error variations include

factors affecting developed muzzle velocity;factors affecting the ballistics of theprojectile; mechanical limitations; and errorsin survey, charts, FDC equipment, and firecontrol instruments.

b. Position velocity errors are assumed tobe the measurement of weapon and systemperformance. They are not considered subjectto change as are weather and othermeasurable nonstandard conditions.Velocity error is muzzle velocity variationplus position velocity error expressed as

meters per second. The computed positionvelocity error should be treated as a constant.The position VE can be used to determine aGFT setting when registration is impractical.The process of determining the GFT settingwithout registering is called met + VE.

Section II.

MET MESSAGES

10-5. CHARACTERISTICSCurrent meteorological conditions must be

measured to correct for nonstandardconditions caused by weather. Thismeasurement is done by the artillery metsection. One of the section's jobs is to samplethe weather at various altitudes. Thesesample weather data are converted,manually or by computer, to give specific

weather information at specific altitudes.These weather data are transmitted to theartillery units in a fixed format called a metmessage. There are five types of metmessages used by the field artillery-ballistic(B), computer (CM), fallout (F), soundranging (SR), and target acquisition (TA).The fallout message is used in nuclear andchemical fallout predictions and will not bediscussed here. The sound ranging metmessage is used by sound ranging platoons indetermining the locations of sound sources.

The target acquisition met message is used byradar platoons of the target acquisitionbattery.

10-6. BALLISTIC METMESSAGE

a. The ballistic met message is a coded

messagecontaining information about

current atmospheric conditions. The twotypes of ballistic met messages provided forartillery fire are type 2 messages, which areused in air defense artillery, and type 3messages, which are used by field artillerycannon units and field artillery rocket unitsfor firing at surface targets. Type 3 messagesare used to solve the met data correctionsheet. The introductory portion of the firingtables for each weapon specifies which typeof met message is to be used for that weapon.

10-3



FM 6-40

DNfRODUCTQOOMETB31 (GROUP 1) 345982 (GROUP 2)

270950 (GROUP 3) 037991 (GROUP 4)

BODY002107 029957012208 029954022309 033953032410 037954042610 039953052812 042951

Figure 10-2. Ballistic met message.

Type 3 messages are used for all elevationsfor all charges for all howitzers inm a n u a l / h a n d - h e l d ca lcu la to r FD Coperations.

b. The ballistic met message is dividedinto an introduction and a body (fig 10-2).

(1) The introduction of the ballistic metmessage consists of four six-charactergroups.

(a) Group 1. The first three letters(MET) in group 1 identify the transmission asa met message. The next letter (B) indicatesthat it is a ballistic met message. The firstdigit (3) indicates the type of met message.The last digit (1) designates the octant of theearth in which the met station is located. Inthis case, 1 indicates that the met station isbetween 90'W and 180'W longitude and thatit is north of the equator (north latitude) (fig10-3). Figure 10-3 also contains the key to theoctant codes.

(b) Group 2. Group 2 designates thecenter of the area in which the met message isvalid. This is expressed in tens, units, andtenths of degrees of latitude and longitude(345 = 34.50 = 30030 ' north latitude and 982 =98.20 = 98.12' west longitude) or, when thenumber 9 is used to designate the octant, thesix digits or letters represent the codedlocation of the met station that produced themessage.

(c) Group 3. The first two digits (27)in group 3 represent the day of the month themet message is valid. The next three digits

N180°W N90OW NO0o N90 0 E N180 0 E

EQUATOR

S180 0 W S9 0 0 W SOO S9 0 0 E S180 0 E

CODE NUMBER OCTAHT CODES

0 North latitude, 00 to 900 west longitude.1 North latitude, 900 to 1800 west longitude.2 North latitude, 1800 to 900 east longitude.

3 North latitude, 900 to 00, east longitude.4 Not used.5 South latitude, 00 to 900 west longitude.6 South latitude, 900 to 1800 west longitude.7 South latitude, 1800 to 900 east longitude.8 South latitude, 900 to 00, east longitude.9 Used for coded identification.

Figure 10-3. Met station octant locations.

S

10-4



FM 6-40

(095) indicate the hour in tens, units, andtenths of hours (095 = 09.5 hours = 0930) themet message becomes valid. The hours referto Greenwich mean time. The last digit (0) ingroup 3 indicates the number of hours themessage will remain valid. The United Statesdoes not attempt to predict the length of timea met message will remain valid. Instead,during combat, the United States normallyobtains new met data every 2 hours.Therefore, the last digit in group 3 of aballistic met message produced by the UnitedStates will always be 0. Some allied nationspredict the length of time a met message willremain valid. These predictions vary from 1to 8 hours. Code figure 9 indicates 12 hours.

(d) Group 4. The first three digits

(037) of group 4 indicate the altitude of themet station (meteorological datum plane[MDP]) above mean sea level in multiples of10 meters (037 = 370 meters). The next threedigits (991) indicate the atmospheric pressureat the MDP expressed as a percentage (to thenearest 0.1 percent) of the International CivilAviation Organization (ICAO) standardatmospheric pressure at mean sea level (991=99.1 percent). When a value is equal to orgreater than 100 percent, the initial digit 1 isomitted.

(2) The body of the met message canconsist of 16 met message lines (00 through15). Each line consists of two six-numbergroups. Each line contains the ballistic datafor a particular altitude zone. Ballistic dataare the weighted average of the conditionsthat exist from the surface up through thealtitude zone indicated by the line numberand back to the surface (fig 10-4).

(a) The first two digits of the firstgroup oh the line identify the altitude zone (00

[surface] through 15 [18,000 meters]). Line 03is used as an example.

(b) The next two digits (24) of the firstgroup indicate from which direction theballistic wind is blowing expressed inhundreds of mils true azimuth (24 = 2,400mils).

(c) The last two digits (10) of the firstgroup indicate the speed of the ballistic windin knots (10 = 10 knots).

ZONE LINE DIRELHEIGHT NUMBER (100's

(METERS) ZZ d

SUFACE oo00

200 01

500 02

1000 03

1500 04

2000 05

3000 06ooomoo

10000 17

12000 12

14000 13

16000 14

180o15

Figure 10-4. Zone height.

(d) The first three digits (037) of the

second group on theline indicate the ballistic

air temperature expressed as a percentage (tothe nearest 0.1 percent) of the ICAO standardtemperature (037 = 103.7 percent). When avalue is equal to or greater than 100 percentfor temperature or pressure, the initial digit 1is omitted.

(e) The last three digits (954) of thesecond group indicate the ballistic air densityexpressed as a percentage (to the nearest 0.1percent) of the ICAO standard density (954 =

95.4 percent).

10-5



FM 6-40

c. The message is recorded on DA Form3675 (Ballistic Met Message) (fig 10-5).

10-7. COMPUTER METMESSAGEThe computer met message, like the

ballistic met message, is a coded messagethat reports the atmospheric conditions inselected layers starting at the surface andextending to an altitude that will normallyinclude the maximum ordinate of fieldartillery weapons that use these data. Unlikethe ballistic met message used in the manualcomputations (where the weather conditionsexisting in one layer or zone are weightedagainst the conditions

in lower layers andreported as percentages of the standard), thecomputer met reports actual average windspeed, air temperature, and pressure in eachlayer. The computer met message is used byFADAC and the BCS and TACFIREcomputers in the computation of theequations of motion used in the computer's

I' U00 ofhIsDfolm 0 oooPFM 6-15; tho popanont aoncy Io Unitod Satoo Conlnontal Army Comman&VPE 0CTAIT LOCATOO DATE TONITE DURAT'OO STATON MuP

wNSG LOLLO10O1 ,(G MY) (HOURS) HEIGHT 'PRESSUREo 1 1GC'sN) ' %OF STOx nun Ann vv_ 00610 hhh I PPp15 / .. /5" 7 1 j':'Z 27 rr:. 0 0.37 , /

BA1LDSTaC gos I3A1SDC AIRLOWIE 6ORECTOORN I SPEED TE(PERATURE DERSTOkU20ER {V(00iGsOGLS) I (KNIOTS) WOF STO) (% F STO)______

H(U%_____

26

Figure 10-5. Ballisticmet message.

10-6



FM 6-40

program. The computer met message isdivided into an introduction and a body andis recorded on DA Form 3677 (Computer MetMessage) (fig 10-6).

a. The introduction of the computer met

message consists of four six-charactergroups.

(1) Group 1. The first five letters(METCM) identify the transmission as acomputer met message. The last figure (digit1) is the designation of the octant of the earthin which the station is located. The octantcode key is the same as the key for theballistic met message.

(2) Group 2. Group 2 in the computermet message is the same as group 2 in the

ballistic met message.(3) Group 3. Group 3 in the computer

met message is the same as group 3 in theballistic met message.

(4) Group 4. The first three digits(049) of group 4 indicate the altitude of themet station MDP above mean sea level in tensof meters (490). The last three digits (987)indicate the atmospheric pressure, in

millibars, at the met station. When the valueis greater than 99.9, the first digit 1 is omitted(for example, 009 = 100.9).

b. The body of the met message consistsof 27 met message lines (00 through 26). Each

line consists of two eight-number groups.Each line contains the actual averageweather data for a particular altitude zone.

(1) The first two digits of the first groupindicate the met line number that identifiesthe zone. The lines are numbered in sequencefrom 00 (surface conditions) through 26. Line00 is used as an example.

(2) The next three digits (260) indicatethe direction from which the wind is blowingexpressed in tens of mils (2,600) true azimuth.

(3) The last three digits (018) indicatethe wind speed expressed in knots (18 knots).

(4) The first four digits of the secondgroup indicate the actual air temperatureexpressed in degrees Kelvin to the nearesttenth of a degree (269.80 Kelvin).

(5) The last four digits of the secondgroup indicate the actual air pressure, in

COMPUTERMETMESSAGEFor use of this form, see FM 6-15; the proponent agency is United States Continental Army Command.

OCTANT LOCATION DATE i TIME ; DURATION STATION , MOPLaLaL a LoLo01 1 (GMT) I (HOURS) HEIGHT. I PRESSURE

or or I (10'sM) ' MB's,o xxx xxx YY G o G : hhh ,

Jf 5O 0 Q 1 9 9 8 7ZONE VALUES

LINE WIND WIND TEMPERATURE PRESSURENUMBER DIRECTION SPEED (1/100K) (MILLIBARS)

(10'sM) (KNOTS)

ZZ ddd FFFTTTT PPPP

00 4260 0a/p nowzt698 0987.0 60 0./8 ,2689 09702 .2o7.0 O.ZQ.0 5503 3 0 0 0 6 0 0 9 0 0

04 0 3 / 0 0 , 3 0 ;2,6__0__V

Figure 10-6. Computer met message.

10-7



FM 6-40

millibars, (0987) to the nearest millibar (987millibars).

10-go MET MESSAGE ERRORSWhen the met message is received by the

FDC, it should be checked to ensure that it iscorrect. The validity of the met messageshould be questioned if any of the followingerrors exist:

a. Ballistic Met Errors. Ballistic meterrors are as follows (fig 10-7):

(1) Drastic changes (over 1,000 mils) orsudden reverses of wind direction from line toline. Ballistic winds should flow in a fairlyuniform manner.

(2) Severe increases or decreases (10 to15 knots) in wind speed from line to line.

(3) Temperature and density changingin the same direction. As temperatureincreases, density should decrease.

(4) Drastic changes (2 percent or more)in density or temperature. Ballistictemperature and density should changesmoothly between zones.

(5) Consecutive messages that do notshow a trend. Consecutive messages shouldshow a trend that relates to the actualweather conditions unless the weatherconditions have changed during sunrise orsunset transition periods or because of afrontal passage, rain, snow, or a rapidincrease or decrease in cloud cover.

Figure 10-7. Ballistic met message errors.

10-8

- = = = =



FM 6-40

b. Computer Met Errors. Computermet errors are as follows (fig 10-8):

(1) Drastic wind direction changes

(over 1,000 mils) or sudden reverses in wind

direction from line to line.

(2) Abrupt increases or decreases (10 to

15 knots) in wind speeds from line to line.

(3) Severe increase or decrease (over 200

Kelvin) in temperature from line to line.

(4) Differences in identification linepressure and surface pressure.

(5) Increases in pressure. Pressure

should decrease smoothly from line to line.

Pressure will never increase with height.

10-9. MET MESSAGE SPACEAND TIME VALIDITY

a. Space C o n s i d e r a t i o n s . Theaccuracy of a met message may decrease asthe distance from the meteorological

sounding site increases.Local topography

has a pronounced effect on the distance thatmet data can be reasonably extended. Inmountainous terrain, dist inct windvariations occur over short distances. Thiseffect extends to much greater heights thanthe mountain tops. Large bodies of water willaffect both time and space considerations ofthe met message because of the land and seabreezes and the effect of humidity on density.Increases in humidity cause decreases in airdensity. It would be impossible to compute an

COMPUTER MET MESSAGEFor use of this form, see FM 6-15; the proponent agency is United States Continental Army Command.

OCTANT LOCATION DATE TIME DURATION STATION MDP

LaLaLa LoLoLo i (GMT) I (HOURS) HEIGHT I PRESSURE

or or 0(1O'sM) MB'sxxx xxx vY GGGG:hhh

qq 96 /;7'/75' 0 0 3 6 9ZONE&SVALUE

_ _ _ _ _ _ _ _ _ _ _ rf-

WINDDIRECTION

(IO's M)ddd

WINDSPEED

(KNOTS)

FFF

TEMPERATURE(1 100K)

TTTT

PRESSURE"(MILLIBARS)

PPPP

303000

04____0s=2 l0 9

10 OVER 1000/( 101 KNOTS, DRASTIC PRESSUREOBVIOUS ERROR CHANGE INCREASE

Figure 10-8. Computer met message errors.

10-9

LINEUMBER

zz

II

ZONE VALUES



FM~ 6-40

exact distance for every combination ofweather and terrain that might exist. Overgently rolling terrain, met messages forartillery are considered valid up to 20kilometers from the balloon release point(met section). The validity distance decreasesproportionately

with the roughness of theterrain and the proximity of large bodies ofwater.

b. Time Considerations. The passageof time may decrease the accuracy of amessage because of the changing nature of%weather. With the present equipment, it isextremely difficult for the artillery metsection to provide met messages morefrequently than every 2 hours over anextended period of time. There are no specificrules for determining the usable time. Thatdetermination will depend on thecharacteristics of the atmosphere, periods oftransition, met section movement, personnel,supplies, equipment, and the altitude of themet message (line number) required by theartillery firing units. When the weatherpattern is variable, the usable time isvariable. If a frontal passage is forecast forthe area, the met section will take a newsounding after the front passes. When the

weather pattern is stable and is forecast toremain so, time between messages may beextended up to several hours depending onthe time of day and existing weatherconditions.

c. Use of Met Data. Results of manystudies based on artillery firing and met datashow that the order of preference of varioussources of met data is as follows:

(1) . A current met message that is lessthan 2 hours old (unless an exchange of airmass has occurred since the met message wasproduced or unless periods of transition areinvolved) and is from a station within 20kilometers of the midpoint of the trajectory(upwind is best). A 4-hour-old met messagemay be used except when day/night

transitions or frontal passages are occurring.(2) A current met message from the

nearest station up to 80 kilometers from themidpoint of the trajectory (upwind is best)and less than 2 hours old.

(3) Met messages over 2 hours old butfrom a station within 20 kilometers of themidpoint of the trajectory.

Section III

COWCURREWW MET

10- 10. CHARACTERISTECSA concurrent met is solved to determine

position constants. Met corrections aredetermined and then subtracted from thetotal corrections to yield position constants.The recommended sequence for solving aconcurrent met is to follow the sequence of thetables in the tabular firing table. Thisrecommended sequence is outlined below.

10-11. SEQUENCE FORSOLUTION OF ACONCURRENT MET

a. Determine and enter the totalcorrections from the GFT setting.

b. Enter the known data.

c. Determine the met line number fromtable A of the tabular firing table.

d. Enter the met message data.

e. Compute A h, height of target abovegun, and chart direction of the wind.

f. Enter the TFT and determine thefollowing:

(1) Complementary range from table B.(2) Wind components from table C.(3) Corrections to temperature and

density from table D.(4) Correction to muzzle velocity for

propellant temperature from table E.

10-10

S



FM 6-40

g. Compute, corrected values fortemperature, density, entry range, crosswind,range wind, and variations from standard.

h. Enter the TFT and determine the

following:

(1) Unit corrections from table F.

(2) Rotation corrections for range fromtable H.

(3) Rotation corrections for azimuthfrom table I.

i. Compute the met deflection correctionand position deflection correction.

j. Compute the met range correction andposition velocity error.

k. Enter variations from standard in theMET FUZE CORRECTION block of DAForm 4200, and determine unit correctionsfrom table J.

1. Compute the met fuze correction andposition fuze correction.

10-12. SOLUTION OF ACONCURRENT MET

The sample problem below describes thesolution of a concurrent met by use of thesteps outlined in paragraph 10-11. Thefollowing known data are given:

From the registration on Registra-tion Point 2:GFT A: Chg 4, Lot XY, Rg 5140, El335, Ti 18.9Adjusted deflection 2757Chart deflection 2755

Adjusted QE 340Direction of fire 0395Lot Y is M3A1 (GB) propellant

From the executive officer:Projectile weight 3 squaresPropellant temperature +820 F

From a map or firing chart:Altitude of registration point 376Altitude of battery 355Latitude 30°N

10-11



FM 6-40

From the met station:METB31 347985 271250 055972005816 010954015816 010956025917 008958036021 004960046023 002962

From the MV record registeringgun:

MVV Chg 4GB, Lot XY = -7.7meters per second

a. Enter the total corrections from sectionI of DA Form 4757 (Registration/SpecialCorrections Work Sheet) (app J) (fig 10-9) onthe met data correction sheet (fig 10-10).

b. Enter the known data (fig 10-10.)Entered data consist

of the following:(1) Charge.(2) Adjusted quadrant elevation.

REGISTRATION/SPECIAL CORRECTION WORK SHEETFor se f th is orm. ee M 6-40, roponent gency s RADOC

SECTION I. REGISTRATION COMPUTATION

:CIEEDRAGEDEFLECTIONCORRECTION

ICHARTANGEM 7 CORRECTED EFLECTION REGISTRATION)

0MTR12IS 11MIL02 REGISTERING IECE ISPLACEMENT F-B +1 REGISTERING IECE ISPLACEMENT ORRECTION.L..R.I....(L-.... ... IMILl

S ADJUSTED EFLECTION Wi J.40 10 ET 2 57

11 MILlREGISTERING IECE DISPLACEMENT ORRECTION 10 CHART DEFLECTION

4 LATERAL ISPLACEMENTL N . 11OMETERS.I I TOTAL DEFLECTION ORRECTION I ILR1'a(1 MILl

ACHIEVEDANGE E 11 2 DRFTCORECIOASHEVOG, - t510METERSI I9-ADJUSTED LEVATION) l 2l 7 11 MILlREGISTERING IECE ISPLACEMENT ORRECTION GRAPHICAL MFIING ABLE OFTI. 13 .-1MI)laAILLR'IMILl

DEFLECTION ORRECTION (9 19 1 RL 2 . ,I ILl

GET SETTING MANUAL METHOD) DEFLECTION ORRECTION

14 OFT CHARGE LOT RANGE ELEVATION TIMETOA FA KY 503,35 18.9 OTLF5 FT CHARGE LOT RANGE ELEVATION TIME

15 2

O6 T CHARGE LOT RANGE ELEVATION TIME L 2 R 5OFT SETTING COMPUTER METHOD)

BCS AMMUNITION ND FIRE NIT RANGE RANGE CORRECTION TIME CORRECTION DEFLECTION ORRECTION17 REGISTRATION

HAND HELD ALCULATOR ESIDUALS DEFLECTION ORRECTION FUZE K RANGEK

FADAC ESIDUALS DEFLECTION FUZE RANGE19

REMARKS

%%.51-10.3 180 TTAL GF

5140ASFORM 7S PETIN COER MOBETE

EDITION F OCTOBER 978 IS OBSOLETE

Figure 10-9. Total corrections.

0

C

10-12

...- ....... .. .. F qri%'pr 0.



MET DATA CORRECTION HEETFer se f slo m. s.Pee M 6-40; roonent cy is TRADC.

BATTlT DATA MIT MESSAGE

cmo OAN .N o mm ofli E0.05500 000000L OoOWImo0100Type.00000000

DAILTM ALT MO

*lJOlA . N A 5 COmioECROSALIc M iulYr(1

ALTOFOP c

@TRYcocO quo WImmalu

WINDCOMPOMETS ND IPFLICTN

mmmota rmoo rc)

" 9nosos or Woo Is I,00z r1 l & O =Cc ? A 4EN THAN NN i1e9 DD

[CTINOF "DO d se

ROT TIONLmmmzc? C)COmm ,l

coum m~c~m~r oocomsco ' 00 '. - mos'l___ TCAon m ECTIONiOF IND Can" L

CRU ID NOSCROIS 115101

moo umo * c uitnqUNITo m comm a

RANG9"NO TT AI MET 9OL$

MET RANGEC OREECTION

KNOW" STANoA VMUIATIONS ROM UNIT

-vRAII lG9II0ONO¢'1

liocm ooc mm c o o o ce

AIR O1114T1

COJAPUTATYM F VIE

•TTAL. iANGO

0 0 ? pullOCRURECTIO

Tam 4iFRPfO3mp w

14V NIT &, AwGIAV Fill I om5yiOeWl TO AL A GICtO

CORMCCTmIO

O00 00* 0.0.000 _______ ocl ..... i_ _ _ _ _ _ _ _ _

mET FUZIE ORECTION

orAIII 4 ETOAM 65.MI U6HSit N AN

- T ,

.AA"GE IND, w514

0

AlIR DENSIT I

o TOTAL FulaPROJWEIGMT Ci .iIO

MEiT uze

T T L FU lEcolin IONI

LOLD , ',%o ..... N IN Z.CORR- 2 A

:G

r CORM

n

I--,,AFORM7440R E P L A C E S

DA F

OR M 6 1 5 ,

1A P R 6 7

,W H I C

;H IS ° B S °

OLT

Figure 10-10. Known data and total corrections.

10-13

FM 6-40



FM 6-40

(3) Chart range.(4) Latitude (nearest 100).(5) Battery altitude (nearest meter and

nearest 10 meters).(6) Target altitude (nearest meter).

(7) Direction of fire (nearest mul andnearest 100 mils).(8) Projectile weight.(9) Propellant temperature.(10) Lazy Z.(11) Total range.(12) Total fuze correction.(13) Total deflection correction (plus

basic formula for determining positiondeflection correction).

(14) Target number.

(15) Date-time group.c. Enter Table A for the appropriate

charge with the adjusted QE, and extract themet line number (fig 10-11). The met linenumber indicates the whole line of metthrough which the maximum ordinate of thetrajectory passes.

FT 155-AM-2

PROJ, HE, M107FUZE, PD, M557

TABLE A

LINE NUMBER

LINE NUMBERSOF METEOROLOGICAL MESSAGE

QUADRANT LINEELEVATION NUMBER

MILS

0.0- 146.3 0

146.4- 280.2 1280.3- 421.8 2421.9- 561.9 3562.0- 686.1 4

686.2- 863.6 5863.7-1119.8 6

1119.9-1300.0 7

NOTE - WHENTHE PROJECTILE MUST HIT THE TARGET ON THE ASCENDING BRANCHOF ITS TRAJECTORY, USE HEIGHT OF TARGET IN METERS TO ENTER THETABLE ON PAGE XXIV TO DETERMINE LINE NUMBER.

Figure 10-11. Line numbers of met messages.

10-14

0

CHARGE4G



FM 6-40

Figure 10-12. Entering the met data.

d. Enter the met message data (fig 10-12).Record the data from the identification lineand the line determined in c above in theMET MESSAGE block. Record the MDPaltitude, wind direction, and wind speedvalues in the other blocks as indicated.

e. Compute A h, height of target abovegun, and chart direction of wind (fig 10-13).

(1) Determine the difference in altitudebetween the battery and the MDP to correctthe values for temperature and density.

A Q CHRRe U TYPE ME SSAGEI

CTNTAREW UNIT

l&-- TI; b C O R C I

AT O BURSTTIME ALT MOPiISALT OF U@TRYS et )

fCTOOfUPRGI:NTSYLT O F TARGETCNETDVLE

HEIGHT OP TA RGT jHAT

G

AL.T OF BIURST

AL.T OF OTRY t)

( 1 AMO V E GUN (A000-

WIND COMPONENTS AND DEFLECTION

V IWHEN Oi IECTION OF BIND ISLESS TN^NN DIR FIR AD D

O.RECTION oPBIND.

DIRECTION OPF 2S c ~ fiCH ART DI EC ION40

Sm

ROTATION L

CORR R

DRIPFT

Figure 10-13. Computation of A h, height of target above gun, and chart direction of wind.

10-15



FM 6-40

(2) Determine height of target abovegun (vertical interval) to the nearest 100meters. It will be used to-determinecomplementary range.

(3) Use the chart direction of the wind

to divide the wind direction into crosswindand range wind components. Subtract

direction of fire from direction of wind todetermine chart direction of wind.

f. Enter table B (fig 10-14) with the chartrange to the nearest listed value and theheight of target above gun to the nearest 100,and extract the complementary range.Record as shown in figure 10-18.

TABLE B

CaiPLEMENTARY RANGEL NE NURSER

FT 155- Ab 2FT 155-AM.2

PROJ. HE. M107 PROJ. HE. M107FUZE. PD. M557 FUZE, PO, M557

CHANGE IN RANGE, IN METERS,TO CORRECT FOR CO2PLEMENTARY ANGLE OF SITE

LINE NUMBERSOF METEOROLOGICAL MESSAGE

LINE RANGE HEIGHT OF TARGET ABOVE GUN -MVETERS HEIGHT OF TARGET ABOVE GUN

[o METERS .400 - 300 -200 -100 0 100 200 300 400 500 600 700

3500-5

3600 -613700 643800 -6639W0 -68

4000 -70

4100 -724200 -7543UO -774400 -79

4500 -82

4600 -844700 -874800 -894900 -02

91 -461 -31-16-18-18

0 1 170000

17181819

34

35363839

52

54565759

71 91 112 j 13373 94 115 13776 97 119 14278 100 123 14681 103 126 15 1

1 6 \

166171/

176

1 1-3437 -19{ 0 1 2 0 f 40f 61 83 106 130 155 18/

-55 -38-57 -39-59 -40-61 -41

-19-20-21-211

-631 -431 -22

00001

202121

23

41424445

46

63656769

71

86 110 13488 113 13891 116 14294 120 147

96 123 151p - t.- ?1i 1f t - i -l I

-65-66-68-70

-44-45-47-48

-22-23-24-24

00

23242525

48495052

73757779

99102105108

127130134138

16469

16016517 0175

180

185190196202 2

. . .I....- - i

5000 -93 -72 -49 -25 0 26 53 82 111 142 174 207 242

5100 -97 -74 -51 -26 0 27 55 84 114 146 179 213 25200 -100 76 - -26 0 28 56 86 117 150 184 219 25300 -103 -79 -53 -27 0 28 58 89 154 189 2265400 -10 -81 -5 -28 0 29 59 91 14 159 195 232

5500 -108 . -83 -56 -29 0 30 61 94 128 163 200 239i±

-114-117-121

-85-87-90-02

-58-59-61-61

-30

-30-31-32

31323233

63656668

-410205

131135139143

168173178183

206212218225

246253261269

29\306\316

6000 -124 -95 -64 -33 0 34 70 108 147 188 232 277 32,

6100 -127 -97 -66 -34 0 35 72 111 151 194 239 2866200 -131 -100 -68 -35 0 74 114 156 200 2466300 -134 -103 -70 -36 0 37 77 118 161 206 254

6400 138 -106 -72 -37 '7 39 79 121 166 213 262 315

6500 -142 -109 -. 0 40 81 125 171 220 271 325

6600 -146 -112 -76 39 0 41 84 129 177 -2 280 3376700 -150 '-115 -40 0 42 86 133 182 235 290 349 46800 -154 J- -81 -41 0 43 89 137 18 243 300 362 426900 -159 -122 -83 -43 0 45 92 142 195 252 312 377 447

7000 -164 -126 -86 -44 0 46 95 147 202 261 324 393 461.

3 4

Figure 10-14. Table B.

10-16

CHARGE4G

S

5600

58005900

2

2

I 1 1 1 1 11

- I - i - ii . i imwr

2 11 & It

II

I

-47

149 - ?3_3,50 --49 -32 35



FM 6-40

g. Enter table C (fig 10-15) correspondingto the chart direction of the wind, and extractthe range wind and crosswind. Record asshown in figure 10-18.

TABLE C

WIND COMPONENTS

COMPONENTSOF

RANGEWIND

KNOT

H1.00

H.99H. 8H.96

H. 2

H.88H.83H.77

H.71

H.63H.56H.47

H.38

H.29H.20H.iD

CHARTDIRECTION

OF WIND

MIL

0

100200300

400

500600700

800

90010001100

1200

130014001500

1600

170018001900

2000

210022002300

2400

250026002700

2800

290030003100

3200

T.IOT.20T.29

T.38

T.47T. 56T.63

T.71

T.77T. 83,T.88

T.92

T. 6T. 98T. 99

Ti1.00

FT 155 AM 2PROJ, HE, M107FUZE, PD, M557

A ONE KNOT WIND

CHART CROSSDIRECTION WIND

OF WIND

MIL KNOT

3200 0

3300 L.103400 L.203500 L.29

3600 L.38

3700 L.473800 L.563900 L.63

4000 L.71

A 1nn 7

KNOT

0

R.10R.20R.29

R.38

R.47R.56R.63

R.71

R.77R. 83R. 88

R.92

R. 96R.98R. 9

L. 83L.88

L.92

L. 96L.98L.99

Li .00

L. 99L.98L.96

L. 92

L.88L.83L.77

L.71

L.63L. 56L.47

L. 38

L.29L.20L. 10

6400 0

NOTE - FOR A COMPLETE EXPLANATION OF THE USE OF THIS TABLE, SEE PARA-

GRAPH 13, EXPLANATION OF COMPONENTSOF A ONE KNOT WIND.

Figure 10-15. Table C.

10-17

CROSSWIND

,,1 vv42C04300

4400

450046004700

4800

490050005100

5200

530054005500

5600

570058005900

6000

610062006300

CHARGE4G

81.00 0

RANGEWIND

KNOT

T1.00

T. 99T. 98T.96

T. 92T. 88T. 83T.77

T.71

T. 3T.56T.47

T.38

T.29T.20T.iO

0

H.10H.20H 29

H.38

H.47H. 56H.63

H.71

H.77H.83H. 88

H.92

H.96H.98H.99

H1.00

8.99R. 98R. 6

R.92

R.888.83R.77

R.71

R.63R.56R.47

R.38

R.29R.20R.10

0

I



FM 6-40

FT 155-AB-2 TABLE 0 CHARGEPROJ. HK. t107 TEMPERATURE 4GFUZE. PD., 57 ANDDENSITY CORRECTIONS

CORRECTIOMS TO TEMPERATURE (DT) AND DENSITY (DO, IN PERCENT,TO COMPENSATE FOR THE DIFFERENCE IN ALTITUDE,

IN ETERS. BETIEEN THE BATTERY AND THE MOP

NOTES - 1. DH IS BATTERY HEIGHT ABOVEOR BELOW THE MOP.2. IF ABOVE THE MOP, USE THE SIGN BEFORE THE NUMBER.3. IF BELOW THE MOP. USE THE SIGN AFTER THE NUMBER.

Figure 10-16. Table D.

h. Enter table D (fig 10-16) with A h, andextract the corrections that must be applied totemperature and density to compensate forthe difference in altitude between the batteryand the MDP. Record as shown in figure10-18.

i. Enter table E (fig 10-17) with thepropellant temperature to the nearest degreeFahrenheit, and interpolate the change tomuzzle velocity. Record the value as shown infigure 10-18. Interpolation is not necessary if

TABLE E

PROPELLANTTEMPERATUAE

EFFECTS N MUZZLEELOCITYDUETO PROPELLANTTEMPERATURETEtTERATURE EFFECT TEMPERATURE

OF ON OFPROPELLANT VELOCITY PROPELLANT

DEGREES M/S DEGREES

-40 -6.4 -40.0-30 -3.6 -34.4a-20 -4.8 -28.9-10 -4.2 -23.3

0 -3.5 -17.8

10 -2.9 -12.220 -2.4 -6.730 -1.8 -1.140 -1.3 4.4

50 -0.9 10.0

60 -0.4 15.6-70 0.0 21.180 0.4 26.790 0.8 32.2

100 1.2 37.8

110 1.7 43.3120 2.1 48.9130 2.5 54.4

Figure 10-17. Table E.

all values have been interpolated previouslyand if a locally produced supplemental tableE has been constructed listing MV changesfor all temperatures. Standard propellanttemperature is +701 F. An increase inpropellant temperature increases muzzlevelocity. A decrease in propellanttemperature decreases muzzle velocity. TableE lists the effects of propellant temperatureon muzzle velocity. Using the sampleproblem, interpolate the change to MV forpropellant temperature as follows:

TEMPERATUREOF

PROPELLANT(oF)

+90+10

- +82+2 -- +80

2 X

10 0.42.(0.4) = IOX

.8 = lo X

.08= X =l

+0.4

EFFECTON

VELOCITY(MIS)

+0.8

x +0.4

+0.4 -_

+800 F+0.1 +20 F (800 - 90 0 )+0.5 m/s +820 F

Therefore,A correction of +0.5 m/s corresponds to apropellant temperature of +821 F.

10-18

IF H 0 +10- 20- 30- +40-1 50- 60- 70- +S80 9 00 OT 0.0 0.0 0.0 -0 .1 . -0 .1 -0 .1A-0.1 0 .2 B0.2+T-0.2 .

DO 0.0 -0.1' -0.2+ -0.3. -0.4' -0.5' -0.6'+ -0.7' 0.8' -0.9'+100- DT -0.2' -0.2' -0.2 -0.3 -0 3 -0.3 0 . 3 - 0 . 4 - 0 . 4 0 . 4 +

DO -1.0+ -1.1+ -1.2+ -1.3' -1.4' -1.5' -1.6' -1.7' -1.8' -1.9' 200- Dr -0.5+ -0.5' -0.5' -0.6' -0.6' -0.6' -0.6' -0 .7 ' -0 .7 ' -0.7'

0W -2.0' -2.1+ -2.2' -2.3' -2.4' -2.5' -2.6' -2.7' -2.8' -2.9''300- OT -0.7' -0.7' -0.7' -0.8'+ 0.8' -0.8. -0.8' -0 .9 ' -0 .9 ' -0.9'

DO -3.0' -3.1' -3.2+ -3.3 -3.4 -3.51 3.6 3 .7 -3 .8 -3 .9I





FM 6-40

j. Compute the corrected values fortemperature and density by applying thevalues extracted from table D to the metmessage temperature and density.

k,. Compute the range by adding thecomplementary range from table B to the

chart range. Express the result to the nearest100 meters.

1. Compute the crosswind and range windby multiplying the wind speed from the metmessage by the crosswind and the rangewind components extracted from table C.Express the values to the nearest knot.

dET DATA CORRECTION SHEETFor ao of *is Form, Noo FM 6-40; proponont agoncy is TRADOC.

OATTERY DATA DET MESSAGECU AD) E CHART AG LATITUDIETPEMIEAAO OCTANT AREA/UNIT

CZ 40a z I 5f46 '~uA'l t - r B9 Il2 -40M r o C,tis. iALT f T N Y ( 7 lI< ,DATE TIME ALTI OP PREssaE

A L - F 1 0 LINE NO. WINIDOlDN WIND WEED AIR TEO&P AIR DEWGTV

AT O aDP

DrY~CWV50

'~ Z 0 a b CORRECTION 1aLTlOA )'TCORRECTIEDVAIUES

C9

ALT OF DUST

ALT OF OTa RWNI

- 3 2 4

HIMIGHYF;TAAG OP NAG c CHART

N G j5

GIND COMPONENTS OA EFLECTION

OWN IREMCTION F WIND NN5SLENATHANDIR PINE ADD 71)74Cor cce{&' cDIRE1CTION OFOPINGO M 4 r C A ' c-10~t->

DIRECTION ROTATIOCNAf~qCORR A

CHART 0iNECTIOO WINODRIFT

. tL =CL ... 3 . N T . C O SDIND SPEDR'COINO o K'' O NOTS:i', .N .Ro s~eo.. • ou T /i # ..;.tUNIT CORR CORR R

RANGME01"D J T TET 0EFLLWINDO ED ODEKfNOTS CORN

1ET RANGE CORREICTION

KNOON STANOARD VARIATIONS ROM UNITVALUS VALUES STANDARD CORECTIOR $ LU IMUS

RANGE WVIND

AIR TEOP,-EIA.T , (7 £7 , //L

NOTATION

MET RANG C AR R

COMPUTATION OF VE

N/S CCORRECTIONPROP C04ANGE MEMIST tRANGE.

T_2P -P. rm .mv ORRESCTION

av MV UNIT 6V RANGE.IM CORRECTION CO RMECTIO0N

. ..... .TOTAL. RANGE

CORR C T ON

OLOVE 'NERVIE 2 U-AVGVIS

Figure 10-19. Determination of corrected values and variations from standard.

10-20

f



FM 6-40

m. -Compute variations from standard byentering the values for range wind, airtemperature, air density, and projectileweight in the MET RANGE CORRECTIONblock and compare to the standard valueslisted (fig 10-19).

n. Enter table F (fig 10-20) with the entryrange. Columns 8 through 19 list unitcorrections for drift, crosswind, muzzlevelocity, range wind, air density, air.temperature, and projectile weight. Extractazimuth corrections for drift and crosswind

FSGRAZEBURST

FUZEM564

1.92.22.52.8

3.2

3.53.84.24.54.9 /

FT 155-AM-2

PROJ, HE, Mi07FUZE, PD, M557

8 9AZ I UTH

CORRECTIONS

DRIFT OW(CORR OFTOL) IKNOT

MIL MIL

0.0 0.00

0.0 0.010.0 0.010.1 0.010.1 0.02

0.2, 0.02

0.3 0.030.4 0.030.5 0.040.6 0.04

0.7 0.04

0.8 0.050.8 0.050.9 0.051.0 0.06

1.1 0.06

TABLE F

CORRECTION FACTORS

CHARGE4G

RANGE CORRECTIONS FOR

MUZZLE RANGE AIR AIR PROJ WTVELOCITY WIND TEMP DENSITY OF I SO

1 M/S 1 KNOT 1PCT I PCT (4 SO STD)

DEC 1 HEAD TAIL DEC INC DEC INC DEC INC

M U M M U M U MUII

0.0 0.0 0.0 0.0 0.0 0.0 0.0 .0.0 0 0

0.6 -0.6 0.0 0.0 0.0 0.0 0.0 0.0 -1 11.3 -- 2 0.0 0.0 0.1 -0.1 0.0 0.0 -2 21.9 -7 0.1 0.0 0.2 -0.1 0.0 0.0 -3 32.5 -2.2 0.1 -0-.., 0.3 -0.2 -0.1 0.1 -4 4

3.1 -2.7 0.2 -0.1 0.5 -0.2 -0.1 0.1 -5 5

3.6 -3.2 0.3 -0.1 0.6 -0.3 -0.1 0.1 -6 64.2 -3,7 0.4 -0.2 0.9 -0.4 -0.2 0.2 -7 74.7 -4.1 0.5 -0.2 1.1 -0.5 -0.2 0.2 -7 85.3 -4.3 0.6 -0.2 1.4 -0.6 -0.3 0.3i -8 8

5.8 -5.0 0.7 -0.3 1.7 -0.8 -0.3 0.3 -9 9

6.3 -5.4 0.8 -0.3. 2.0 -0.9 -0.4 0.4 -10 106.8 -5.8 0.9 -0.4 2.3 -1.0 -0.4 0.4 -10 117.3 -6.2 1.1 -0.4 2.6 -1.1 -0.5 0.5 -11 11

7.9 -6.6 1.2 -0.5 2.9 -1.3 -0.60.6 -2 .12

. ..... ,

I

RANGE

M

0

100200300400

500

600700800900

1000

110012001300

14001500

1600 84.4 5. 1.2 0.07 8.8 -7.3 1.5 -0.6 3.6 -2.6 -0.7 0.7 13 141700 90.0 5. 1.3 0.07 .3 -7.-7 1.7 -0.6 4.0 -. 7 0.8 0.8 -14 14

1800 95.6 5. 1.4 0.07 9.8 -8.1 1.8 -0.7 4.4 -1.8 -0.9 0.9 -14 141900 101.3 6., 1.6 0.08 10.3 -8.4 2.0 -0.8 4.7 -2.0 -1.0 1.0 -15 16

2000 107.0 6.6 1.7 0.08 10.8 -8.8 2.2 -0.8 5.1 -2.1 -1. 1.1 -16 16

2100 112.8 6.9 1.8 0.08 11.3 -9.2 2.3 -0.9 5.5 -2.3 -1.2 1.2 -16 172200 118.6 7.3 1.9 0.09 11.7 -9.5 2.5 -1.0 5.8 -2.4 -1.3 1.3 -17 172300 124.4 7.6 2.0 0.09 12.2 -9.9 2.7 -. 0 6.2 -2.6 -1.4 1.4 -17 182400 130.3 8.0 2.1 0.09 12.7 -10.2 2.8 -1.1 6.6 -2.7 -i.5 1.5 -18 19

2500 136.2 8.3 2.2 9.10 13.1 -10.6 3.0 -1.2 6.9 -2.9 -1.7 1.6 -19 19

2600 142.2 8.7 2.3 0.10 13.6 -10.9 3.2 -1.3 7.3 -3.0 -1.8 1.8 L-g 202700 148.2 9.1 2.5 0.10 14.1 -11.3 3.4 -1.3 7.6 -3.2 -1.9 1.9 -20 202800 154.3 9.1 2.6 0.11 14.5 -11.6 3.5 -1.4 8.0 -3.3 -2.0 2.0 -20 21

2900 160.4 9 2.7 0.11 15.0 -12.0 3.7 -1.5 8.4 -3.4 -2.2 2.2 -21 22

3000 166.6 0. 2.9 0.12 15.4 -12.3 3.9 -1.6 8.7 -3.6 -2.3 2.3 -21 22

3100 172.9 10.5 3.0 0.12 15.9 -12.7 4.1 -1.6 9.1 -3.7 -2.5 2.4 -22 23

3200 179.2 10.9 3.1 0.12 16.3 -13.0 4.2 -1.7 9.4 -3.9 -2.6 2.6 -22 243300 185.5 11.3 3.2 0.13 16.8 -13.4 4.4 -1.8 9.8 -4.0 -2.7 2.7 -23 243400 191.9 11 3.4 0.13 17.3 -13.7 4.6 -1.9 10.1 -4.1 -2,9 2.9 -23 25

3500 198.4 12.0 3.5 0.13 17.7 -14.0 4.8 -1.9 10.4 -4.3 -3.1 3.1 -24 26

Figure 10-20.

2

ELEV

MI L

0.0

5.110.115.220.3

25.4

30.635.841.146.4

51.7

57.162.567.973.4

78.9 1.4 -0.5 3.3 -1.4 13 13

Table F.

10-21

CHARGE4G

10 11 12 13 14 isi 61171181191

-0. 71 0.6.4 1 -70

I I r-r



FM 6-40

from columns 8 and 9 and record as shown infigure 10-21. Extract the-values in bothcolumn 10 and column 11, because it isunknown at this time whether the MVV-willbe an increase or a decrease. Extract the other

values and record.

Met*or

HEIGHT OF TA R G E T C O M P PG CHART RG ENTRY RG(hmt) MOViZGUNM)I I

Figure 10-21. Entering unit correction factors.

10-22


H E N DIRECTION OF WIND IS 4LESS TH4AN DIR FIRE ADD-/ T C T . t c LRR2DIRECTION OF OIO 57.. 0 0 - 1ET DF CO MI

Po5 DF C O R R R T. .... .. . ..

CORR Q

C H A RT DIR ECTIONOF WVIND. j 0Qor)DRIFT

o WINDS P E D .o t KNOTS' q C R O S N D IWIDSEDCtp 7-R 1: UNIT CORR C O R RA

WIND SPEED 7 COM H KNOTS DRF L

MET RANGE CORRECTION

KNOWN STANDARO VARIATIONS FROM UNIT PLUS tlNUSVALUES VALUES STANDARD CORRECTIONS

RANGI O O IT

AIR TEMP, 0 2 100 L _____ 1

(372_ I 2 K 5 64 a/PROJ W-EIGHT07 3 'tLZl 1 :2/ -- ,31D00_ROTATION

MET ..A N G E C O R R 1

COMPUTATION OF VEVE 0 TOTAL RANGE 240

VE CORRECTION

PROP 2. CHANGETO MV -ETlRANGE4TEMP F FOR PRO'3 TEMP J5 5CORRECTION

Mv UNIT AV RANGE

M/S CORRECTION CORRECTION

TOTAL RANGEr

C O R R E C T I O N

OLD VE NEW VE 2 AVG VE --

MET FUZE CORRECTIONVA~ql~t~l

Z2

11

V AP41 A I ION UNITFROM



FM 6-40

o. Enter table H (fig 10-22) with the entryrange to the nearest listed value and theazimuth of fire to the nearest listed value. Ifthe azimuth is between 0 and 3200, enter thetable from the top. If the azimuth is between

3200and 6400, enter it from the bottom. The

table lists corrections that are applied torange to compensate for the earth's rotation.

.... .. wAnr ;

FT 155-AM-2

PROJ, HE, M107FUZE, P0, M557

RANGEMETERS

500

100015002000

2500

3000350040004500

5000

5500600065007000

7500

8000

8000

7500 -1+ -1+

TABLE HROTATION - RANGE

CORRECTIONS TO RANGE, IN METERS, TO COMPENSATEFOR THE ROTATION OF THE EARTH

AZIMUTH OF TARGET - MILS

03200

0

000

0

0000

0

0000

0

0

200 4003000 2800

0 -1+-1 -2+

1+ -3+-2+ -3+

-3+

32+-3+

43+

-4

-4+

-4+-4+

-4+

-3+

-4+

-5+-5+-6+-6 +

-7+

-7+8+-8 +

-8 +

7+

* -*2+ * -5

600 8002600 2400

-1+ -2+-2+ -3+-4+ -5+-5+ -6+

-6+ -7+

-7+ -9+-8+ -10+-9+ - 11+-9+ -12+

10+ -13+

11+ -14+11+ -14+

-11+ -14+-11+ -15+

-11k -14+

-10+ -13+

-6+ -7+ -8+ -9*

2 -2 -2+ -3+-1+

7000 0 0 +1- +1- +1- +1- +2 - +2-6500 0 +1- +2- +3- +4- +5- +5- +5- +5-6000 0 +2- +3- +5-1+6- +7- +8- +9- +9-5500 0 +2- +5- +7- +9- +10- +11- +12- +12-

5000 0 +3- +6- +9- +12- +14- +15- +16- +16-

4500 0 +4- +8- 412- +15- +18- +20- +21- +22

AZIMUTH OF TARGET- MILS

NOTES - 1. HEN ENTERING FROM THE TOP USE THE SIGN BEFORE THE NUMBER.2. WHEN ENTERING. FROM THE BOTTOM USE THE SIGN AFTER THE NUMBER.3. AZIMUTH IS EASURED CLOCKWISE FROM NORTH.

4. CORRECTIONS ARE FOR 0 DEGREES LATITUDE. FOR OTHER LATITUDESMULTIPLY CORRECTIONS BY THE FACTOR GIVEN BELOW.

LATITUDE (DEG) 10 20 30 40 50 60 70

MULTIPLY BY .98 .94 .87 .77 .64 .50 .34

Figure 10-22. Table H.

4G

i 4 i t i

-19+-20+-20+-21+

-20+

-18+

-9+

-3+

3200 3400 3600 3800 40006400 6200 6000 5800 5600

4200 4400 4600 1 48005400 5200 5000 4800

10-23



FM 6-40

The sign associated with the correction isminus when entering from the top and pluswhen entering from the bottom. The valueextracted is for 0 degrees latitude and must bemodified by a correction factor shown belowthe table. Record correction factors as shownin figure 10-23.

CHARo3,,WOF°..o. .. ..o...: TAIL

MOD122 lzo N c o t p " M A O KNOTS CORR R

t 2T PANGE COPM[ECTION

KsOaON STANOARO VARIATIONS FROM UNIT PLUS MINUSVALUES VALUES ST ANDARD CORRECTIONS P

T T

R A N G O U D o

AIR DENSITY tO3p 00% z4 L...... _____ _______ZZo ,,, ..

_>o_ 1o? _ , I _ _ _ _ -31.0ROTATION C < g(

MET RANGE COAR 1

COMPUTATION OF V2

TOTAL RANGEV. CORRECTION4

P R O P CHANGE TO MV MET RANGETEMP V PORPROP TIEMP is CORRECTION

MV UNI6T VRANCOEw CORR CONNECTION

..... ANGE

Figure 10-23. Rotation correction (range).

p. Enter table I (fig 10-24) with theentryrange and azimuth of fire expressed to the

nearest 100 mils. Table I lists correctionfactors to azimuth for rotation. Each pagecontains a table for the appropriate latitude.For northern latitudes, enter the table fromthe top. For southern latitudes, enter it fromthe bottom. Enter the sign before the numberwhen entering from the top. Enter the signafter the number when entering from thebottom. Extract the appropriate value andrecord as shown in figure 10-25.

10-24

S

S



FT 155-AM-2 TABLE I CHARGE4G

PROJ, HE, M107 ROTATION - AZIMUTHFUZE, PD, M557

CORRECTIONS TO AZIMUTH, IN MILS, TO COMPENSATE

FOR THE ROTATION OF THE EARTH

30 DEGREES NORTH LATITUDE

AZIMUTH OF TARGET M-ILS

RANGE 0 400 800 1200 1600 2000 2400 2800 3200METERS 6400 6000 5600 5200 4800 4400 4000 3600 3200

500 LO,1R LO.1R LO.1R LO.1R LO 1R LO R LO.1R LO.1R LO1R1000 LO.IR LO.1R LO 1R LO.1R LO.1R LO.1R LO.1R LO 1R LO.1R1500 LO.2R LO.2R LO.2R LO.2R LO.2R LO.2R LO.2R LO.2R LO.2R2000 LO.2R LO.2R LO.2R LO.2R LO.2R LO.2R LO.3R LO.3R LO.3R

2500 LO.3R LO.3R LO.3R LO.3R LO.3R LO.3R LO.3R LO.3R LO.3R

3000 LO.3R LO.3R LO.3R LO.4R LO.4R LO.4R LO.4R LO.4R LO.4R3500 LO.4R LO.4R LO.4R LO.4R LO.4R LO.5R LO.5R LO.5R LO.5R4000 LO.4R LO.4R LO.5R LO.SR LO.5R LOR.5 LO.6R LO.6R LO.6R4500 LO.5R LO.5R LO.SR LO.5R LO.6R LO.6R LO.6R LO. R LO.7R

5000 LO. 5R LO.5R LO.6R LO.6R LO. 7R LO.7R LO.7R LO.8R LO.BR

5500 LO.6R LO.6R LO.6R LO.7R LO.7R LO.8R LO.8R LO.9R LO.9R

6000 LO.SR LO.6R LO.7R LO.7R LO.8RLO.9R L1OR L1 OR L1.OR

6500 LO.7R LO.JR LO.7R LO.8R LO.9R L1 OR L1.1R L1.1R L12R7000 LO.7R LO.7R LO.8R LO.DR L1.OR L1.1R L1.2R L1.3R 1.3R

7500 LO.R LO.BR LO.9R L1.OR L.1R L1.3R L1.4R L1.5R L1.6R

8000 LO.7R LO.8R LO.DR L1.1R L13R L1 .R L1.7R L1 R L1.YR

8000 LO.5R LO.6R LO.8R L12R L1.6R L2.IR L2.4R L2.7R L2.7R

7500 LO.3R LO.4R LO.7R L1.2R L1.8R L2.3R L2.8R L3.2R L3.3R

7000 0.0 LO.1R LO.5R LI.iR L1.8R L25R L3.1R L3.5R L3.786500 RO.3L RO.1L LO.4R Li.iR L1.9R L2.7R L3.4R L3.DR L4.OR6000 RO.5L RO.4L LO.2R L1.OR L1.9R L2.DR L3.7R L4.2R L4.4R5500 RO.9L RO.6L 0.0 LO.DR L1.DR L3.OR L3.DR L4.5R L4.7R

5000 R1.2L RO.DL RO.3L LO.SR L2.OR L3.2R L4.2R L4.DR L5.1R

4500 Ri.SL Ri.3L RO.SL LO.BR L2.OR L3.3R L4.4R L5.2R L5.4R

3200 2800 2400 2000 1600 1200800 400 0

3200 3600 4000 4400 4800 5200 5600 6000 6400

AZIMUTH OF TARGET - MILS

30 DEGREES SOUTH LATITUDE

NOTES - 1. WHEN ENTERING FROM THE TOP USE THE SIGN BEFORE THE NUMBER.2. WHEN ENTERING FROM THE BOTTOM USE THE SIGN AFTER THE NUMBER.3. R DENOTES CORRECTION TO THE RIGHT, L TO THE LEFT.4. AZIMUTH IS MEASUREDCLOCKWISE FROM THE NORTH.

Figure 10-24. Table I.

*WHEN IRtECTION oF WINDI5

LESS THAN DIR FIRSADD

DIRECTIONf 'WINDO .Q~IMOTATIONL

D E C I OCOR

Figure 10-25. Rotation correction (azimuth).

FM 6-40

10-25



FM 6-40

q. Compute the met deflection correctionby multiplying the crosswind unit correctionfactor (table F, column 9) by the crosswindvalue and recording as shown in figure 10-26.Then total the values for rotation, drift, andcrosswind and express to the nearest mil.This value represents that part of the totaldeflection correction due to measurable (met)conditions.

r. Compute the position deflectioncorrection (constant) by subtracting the metdeflection correction from the total deflection

correction. This value represents that part ofthe total deflection correction due tounmeasurable (position) conditions.

s. Compute the met range correction bymultiplying the variation from standard inthe MET RANGE CORRECTION block bythe unit correction factors. Record thesevalues in the proper column (to the nearest0.1). Add the columns. Algebraically add thesmaller value to the larger value, and expressthe result to the nearest meter. Record asshown in figure 10-26.

Figure 10-26. Met deflection correction and position deflection correction.

10-26

0

MET DATA CORRECTION SHEETFor uo .f his orm, o* FM 6.40; roponcam gency is TRADOC.

OATTEDY DATA UET UESSAGE

CaD GE ADJ E CHARL. . T]. DE .PE5 .ESAOE. O C T N T tIEA IT

ALTOfr R T

ALT o oRaFL o 0S D0 5 _I

HlGTor AacETr CONESA IH


or...... o . 59cC . -7'7Cr- ,,,'COALz9.

ANOT OREICTIO Pr

also . N

ALDTIOFTARGT3GiiCORiiCTDViii

PRJ"EI T J 3 Z {UqRST

NO MPTTRATION F E

vALTSFS DoT coR OY

VDCOMPUNITAMDDFETIONOFV

C H E N D I EI N.f..D.S.. .',A Z jLESS ., .... ... o sF61411= ?.-400"iREru , ,or INOD ;nO 9PC

S



FM 6-40

t. Compute position velocity error. Thetotal range correction represents thecorrection for all nonstandard conditions.The met range correction represents thecorrection for met nonstandard conditions.The AV range correction represents what isleft and is determined by algebraicallysubtracting the met range correction from thetotal range correction. The symbol A Vrepresents the total variation from thestandard muzzle velocity, and the A V rangecorrection represents the magnitude of thecorrection, in meters, required to offset thevariation in muzzle velocity. Since MV ismeasured in meters per second, the A Vrange correction must be converted frommeters to meters per second to express thetotal variation from standard ( A V). Theconversion is accomplished by dividing theA V range correction by the appropriate MVunit correction factor extracted from table F.Determining which correction factor to userequires a complete understanding of the AVrange correction. A positive A V rangecorrection shows that an increase in range isneeded. It follows that the velocity developedwas not enough to achieve the range desired.Therefore, the MV was less than standard, ora decrease. Since the velocity was a decreasevalue, the decrease unit correction factor isused. The unit correction factor indicates howmany meters correction is necessary for each1-meter-per-second decrease from thestandard. When the MV decreases fromstandard, a plus range correction is needed.When the MV increases from standard, aminus range correction is needed. In thissample problem, a plus AV range correctionhas been determined (+216), indicating adecrease in muzzle velocity (fig 10-27). The AV range correction (+216) is divided by the

MV unit correction factor (+24.9) todetermine

the amount of decrease in muzzle velocity.The result is expressed to the nearestone-tenth of a meter per second. Since the MVhas been determined to be a decrease fromstandard, the variation must be a minus,yielding a -8.7 A V. AV represents the totalvariation from the standard muzzle velocity.This total variation is made up of propellanttemperature effect, which can be measured;the position VE, which is due to elements thatcannot be easily measured (for example,chart errors, survey errors, tube wear, andprojectile ballistic coefficient); and muzzlevelocity variation. Since the total ( A V) is

known (-8.7) and a part (+0.5) due topropellant temperature is known, theremaining part (VE) can be determined byalgebraically subtracting the change to MVfor propellant temperature from 4 V ([-8.7m/s] - [+0.5 m/s] = [-9.2 m/s]). The positionVE is determined by algebraicallysubtracting the value of the MVV from theVE ([-9.2 m/s] - [-7.7 m/s] = [-1.5 m/s]). TheVE, as determined above, may change over

time but is considered valid until a new VE isdetermined from a later registration andconcurrent met or a new MVV is determined.The VE is the sum of the MVV and positionVE ([-1.5 m/s] + [-7.7 m/s] = [-9.2 m/s]). TheMVV is constantly updated (chap 13).However, the position VE is a constant for allprojectile combinations in that firingposition except for the M712 Copperheadprojectile.

LL~)

(J 0 )(0)

Figure 10-27.- Met range correction and position velocity error.

10-2

IET DATA CORRECTIONSHEETFor use of this orm, see M 6-40. propsAen agency is RADOC.

BATTERY DATA MET MESSAGE

C A R G E A D J O E L T OTYCTANT ARE /oIT

UTS ...... IP/(571ALT P TA R E T

...... 2-7 . ± 4-2 .

ALT F iM ( s 7 f . *

WIND OMHPONENTS N DEFLECTION

&Zcc.... ... ir PoA t

ALT OFTAR-I§ote)ar CotttOLer)

CATG..ET C0

CAT Fin [STIhOr

IN

,m o0oS)Ec o u p../ T.S C m m . ..

MET RANGE CORRECTION

i[ IN s~rIN O~MP @A, NENTS DrEFLCI ONT

Lit.THN..IR1&DDI & . 7 .

.... c. a7.L 4.. -3,t

VE-MuOTATVE

~~-~t2. G777.- Y A e ~ ~ n g E O ~ ___Comm _

us - *TOTAL RANGE.~ ~:~'~ ~CORRECTION 4

LAV* .; T 12 9AV ANGEMS CORS(CTION-5 4.l CORRECTION

IT TAIANGE

Figure10-271etrangecorrecion ad postion EoCityerror

10-27

FM



FM 6-40

u. Enter variations from standard in theMET FUZE CORRECTION block (fig 10-28).

COMPUTATION OF VE

VE T O TA L R A N G EMTUZCRETCORRECTION

P R O P CHANGE TO MV MET RANGETEMP &F F O R PRO. T EMP M / S C O R R E C T I O N

V MV UNITAV RANGEM/ S C O R R E C T I O N C O R R E C T I O N

TO AL R ANG E

CORRECTION

OLD VE +' NEW VE 2 Z VG VE M

MET FUZE CORRECTION

VARIATION...... ..'FROM C O R R E C T I O N P L U S ,o US 3 9; Z

ST ANOARO ......

,v -0

RANGE WIND ./11/.-13

AIR TEMPO TO N

AIR DENSITY ~ 2 _ _ __ _

O ~ ,....~TOTAL FUZEPROJ WEIGHT ILSCORREC TION

MET FUZECORRECTION

FLI'ZECORRECTION

TOTAL FUZEI I ORREC IONMET FUZE CORR CORRECTIOL

O L D F C.rP N E W FZ (ORR "2" 2 AV G F-Z ORR

TA R 'T

N )&FPT2 IATTFRyDATE TIME

DA, M 4200 ,REPLACES DA FORM 6 15, 1 APR 7., WHICH IS OBSOLETE

Figure 10-28. Entering variations from standards.

v. Enter table J (fig 10-29) with the fuzesetting corresponding to the adjustedelevation expressed to the nearest whole fuzesetting increment, and determine unitcorrections. Extract the values from theappropriate increase or decrease column.

w. Enter unit corrections from table J inthe MET FUZE CORRECTION block (fig10-30).

x. Compute the met fuze correction in thesame manner as the met range correction (fig10-30).

FOLDOUT 10-27 10-28



FM 6-40

TABLE J

FUZE CORRECTION FACTORS

FT 155-AM-2PROJ, HE, M557

FUZE, MTSQ, M564

17FS

0

1234

5

6789

10

11121314

15

16171819

20

21222324

25

26272829

30313233

Figure 10-29.Table J.

MI PFUZE ORRECTION

sTF 41"

, 9.7 -o.o52-RAG WN.T 51403.351,.9

" D...1- -0.010

......? I. +ooi iq~AR. .NSTY 2.3 +0.0oS ___

Figure 10-30. Entering unit correction values.

10-29

CHARGE4G

2 35 7 B10 11

FUZE CORRECTIONS FOR

MUZZLE RANGE AIR AIR PROJ WT

VELOCITY WIND TEMP DENSITY OF 1 S01 M/S 1 KNOT 1 PCT I 1PCT (4 SO STD)

DEC INC HEAD TAIL DEC INC DEC INC DEC INC

-. 006 .006 .000 .000 -. 001 .000 .000 .000 .011 -. 01 1

-. 049 .042 .001 .000 -. 001 .01 007 -. 007 .015 -. 05-. 012 .011 -. 00 .00 -. 003 .001 .000 -. 000 .020 -. 20

-. 014 .013 -. 001 .001 -. 004 .002 .001 -. 001 .0824 02 4

-. 017 .016 -. 002 .001 -. 005 .003 001 -. 001 .028 -. 028-. 052 .018 -. 002 .001 -. 007 .003 .001 -. 001 .038 . 03 2

-.022

.020 -. 003 .001 -. 032 .004 .002 -. 001 .035 -. 03 6

.025 .022 -. 04 .002 -. 034 .04 .002 -. 002 .039 -. 040

-. 027 .056 -. 004 .002 --. 125 014 02-.02 .042 -. 044

-. 030 .026 .05 .002 -. 014 .006 .003 -. 003 .045 -. 047

-. 032 .021 -06 .002 i-.015 .007 .003 -. 003 .049 -. 051

-. 035 .030 -. 014 .003 -. 017 .007 .004 -. 04 .052 -. 055

2 -77 .066 .007 .003 -. 018 .008 .004 -. 004 .055 -. 059

-. 039 .04 - .007 .00 -. 00 .016 .015 -. 04 .5 -. 261-. 042 .036 -. 008 .. 003 -. o22 .009 .005 -. 005 .062 -. 066

-. 044 AN3 -. 009 .004 -. 023 .010 .006 -. 006 .065 -. 070

-. 047 .040 -. 009 .004 -. 025 .010 .006 -. 006 .068 -. 073-. 049 .042 -. 010 .004 -. 026 .011 .007 -. 007 .071 -. 077

-. 052 .044 -. 010 .004 -. 027 .011 .008 -. 007 .074 -. 081

-,.054 .046 -. 016 .005 -. 029 .012 .008 -. 008 .078 -. 084

-. 057 .048 -. 01i .005 -. 030 .012 .009-.009 .081 -. 0881 . 059 .050 -. 012 .005 -. 031 .013 .010 -. 009 .084 -. 091

-. 62 .052 -. 012 .005 :-.032 .013 .010 -. 010 .087 F. 095

i-. 064 .054 -. 013 .006 ,-.034 .014 .011 -. 011 .090 1-. 99

i-.067 .056 -. 013 .006 -. 035 .014 .012 -. 012 .093 -. 103

' .069 .059 -. 013 .006 -. 036 .014 .013 -. 012 .096 -. 107

-. 0o72 .061 -. 014 .006 -. 037 .015 .013 -. 013 ,100 -. 110

) -. 074 .063 -. 014 .006 -. 038 .015 .014 -. 014 .103 -. 114

) . 077 .065 -. 015 .007 -.039 .015 .015 -. 015s .107 -. 118

.-. 079 .067 -. 015 .007 -. 040 .016 .016 -. 016 .110 -. 121

- _ 082 .070 -. 01_5 .007 -. 041 .016 .017 -. 016 .114 -. 12.5

3 . 084 .072 -. 01.5 .007 -. 041 .016 .018 -. 017 .118 -. 128

4 -. 8 074 -. 016 .007 -. 042 L.017 .019 -. 018 .122.-132

-. 5 9 077 -. 016 .0 -. 043 [ .017 •0 _. 19 .127-.135



FM 6-40

Figure 10-31. Fuze correction factors and met fuze correction.

y. Compute the position fuze correction(constant) by algebraically subtracting themet fuze correction from the total fuze.correction as shown in figure 10-31. Acompleted concurrent met is shown in figure10-32.

Note. The pos i t ion fuze correct ion(constant) determined should be considereda fuze characteristic, not a correction forexisting weather conditions.

10-13. POSETErONCONSTANTS

The purpose in solving a concurrent met isto isolate the position constants. Theseconstants can be used later with subsequentmets to obtain met +VE GFT settings withoutconducting another registration.

a. When a registration is fired and aconcurrent met (valid ballistic met) isavailable, the met will be solved to determineposition constants. Position constants areconsidered valid only for the position inwhich they are determined.

10-30Atti~L&SAS&.tm~b6 alia ia



FM 6-40

MET ATA ORRECTIONSHEETFor uso of thi. orm,*.. FM 6-40; proponool agency s TRADOC.

BATTERY DATAIMEMSAG

_____tl TYE95to rTAT Alo9Atd EC Q ?O4T~sm IrLo .IC-Tt 2

A3 ko l 1A21 ..PED.I219z 'iPOTTRNGECORRECTION

COMPUATIONOF Y

I up *'F OR PIO v NO - CORRfCFION

~S'~Ar~t: '~j19k20# TPUZE CORRECTION_ _ _ _ _ _ _ _

t - - *A--VARITIO UNTii . A L

FRO CORECION PILUS iku

STA * o N r - G f l A _ _ czOt

A rv 0 A~

P)Pt)

I))

9U

10-31

DAFORM4 0 RE P L A C E S D A F 0RMG6 15. 1 A P R 6/7, WH ICU CUSL E

Figure 10-32. Completed concurrent met.

0



FM 6-40

b. When a unit has displaced to a newposition and cannot register immediately, theMVV and the position fuze constant from thelast position may be used as a basis todetermine a met +VE GFT setting by solvinga subsequent met. Use of this technique mayincur slight inaccuracies, but it will producethe most accurate data possible until aregistration can be conducted. Any firemission that is used to determine, totalcorrections is a registration. As soon aspossible, new position constants based on

firing are determined in the new position.Once new position constants are determined,the position constants from the old positionshould not be used.

Note. The position deflection constantshould not be transferred from an oldposition to a new position unless commonsurvey directional control exists betweenpositions.

Section IV

SUBSEQUENT MET

10-14. CHARACTERISTICSA subsequent met is solved to determine

new total corrections when registration is notpossible. Solving a subsequent met producesnew met corrections, which are added to theposition corrections determined from theconcurrent met. Adding the met and positioncorrections yields new total corrections thatare used to determine a new GFT setting.

10-15. SEQUENCE FORSOLUTEON OF ASUBSEQUENT MET

Note. Asterisks indicate the values thatmay be the same as those for the concurrentmet if the battery and met station have notmoved. If the battery moves, the MVV andthe position fuze correction will be valid inthe new position. If common direction existsbetween positions, the position deflectioncorrection is also valid in the new position.

a. Enter position deflection correctionand position fuze correction, and computeand enter VE (position VE + MVV = VE).

b. Enter known data.

c. Enter met line number and metmessage data. .

*d. Compute A h and height of targetabove gun.

e. Compute chart direction of Wind.

f. Enter tables and determine, thefollowing:

*(1) Complementary range from table B.(2) Wind components from table C.

*(3) Corrections to temperature anddensity from table D.

(4) Correction to MV for propellanttemperature from table E.

.*g. Compute corrected values fortemperature, density, and entry range.

h. Compute crosswind and range wind.i. Compute variations from standard.

j. Enter tables and determine thefollowing:

*(1) Unit corrections from table F.*(2) Rotation corrections for range from

table H.*(3) Rotation corrections for azimuth

from table I.

10-32



k. Compute met deflection correction andtotal deflection correction.

1. Compute met range correction, totalrange correction, and adjusted elevation.

m. Enter variations from standard in theMET FUZE CORRECTION block, anddetermine corrections from table J.

. n. Compute met fuze correction and totalfuze correction.

o. Determine GFT setting.

10-16. SOLUTION OF A

SUBSEQUENT ME TThe sample problem below describes the

solution of a subsequent met by use of thesteps outlined in paragraph10-15. Theposition constants and known data fromparagraph 10-12iwill be used. The followingmet message is valid (notice that met stationhas moved):

METB31 342988 271450 029088002216 951036012320 950040022621 942052032921 941058043125 940060

Propellant temperature +850 F

The updated MVV for charge 4GB, lot XYcorrection is -7.6 meters per second.

a. Enter the position deflectioncorrection, enter the position fuze correction,and compute and enter VE as shown in figure

10-32.b. Enter known data as shown in figure

10-33. The following data are always knowndata in a subsequent met if the battery andmet station have not moved: charge, chartrange, latitude, battery altitude, targetaltitude, altitude of the MDP, A h corrections,height of target above gun, comp range, entryrange, direction of fire, crosswind unitcorrection factor, drift correction, rotationcorrection, proj ectile weight, propellanttemperature, and values for a decrease orincrease in muzzle velocity. In this problem,the met station has moved, so MDP altitudeand A h have changed.

MET ATA CORRECTIONHEETFor uss f his IomsoeFM 6-40; ropooso? OOnEY s TRADOC.

SATTEET DATA MET MESSAGE

LHOJROE ILOJ 9 CART00 j A C S T r U E 0055001 RENKOCTN oNKfloMI

C~oS MY? IOUTT 'L<' IUtI00 PO

ALTOF MODP ~2 1EELOO A 6 CORMELCTi0R

OPOOENoal0 -r I

0LSP-Z 5_- "_____ __ _ __ _ME1POFOP C C ECOP O II4W5o0"I AG oup no CHAR . Talfa............ N .Wtl oI 14o r 14 oP

IND COMPONENTS ID DEFLECTION

OMENDIRECTION f IND..o 0f&% V,tLS TRMn MM1 IM COO $ U C .

"M-OPMSDr t% C o t .

DIRECT MC)00%O R

COURT Re TiOCOP 1INDCORR a ,

c o S S WNDRS %L 5CROIS 0105"NO S COUP MONKNOTSCON

mooD SE Dcoop 0 CR00KNOS coRN

MET RANGE CONNECTION

K N O N S MC S VRIATNS o om oUNIT PLUS MINUSV0.1051 UALUES [ SyTANDOCRO CONNECTIORS

7 ~IT TA M MM1?00%

ONCA ESORT Es S

........ + AA,V ,. . . . .SO -- A.B.m -

PoS VE 4M VV%=JE

-t. + -t-) = -I.... . T R•ANGE ORRn

COMPUTATION F YE

no b )TOTSAL MRN* T N

PROPHANG TOMV9. CONCTI NTam9FOR0P0 9TmC 9 oIS

mv UlIl 4 & V I G&EMWsCORRCTION CORRECTIO

TOTAL ANGE1

0ORET 0

OLD I L f4r -C - oITVGVIE MIS

MET FUZE CORRECTION

DAUA420 A M I C IS OFROM PLiS3 .K w

0

RAINGE lNO ''. +

AIRn ENSITYV ,•. . ,

0 TO TAL UZE

F~ UZ

MET U CRRPR,=~p

Te4, Q 00 AI Tr 0o-Vt r+,ir

FARM0 PLAESA RM15,+.P ,HI ,SoBSoLCDAIIJAN744

Figure 10-33. Known data.

FM

10-33 FO

ICONNECTED ALVESI

l 0 -33



FM 6-40

METDATA COR CTION HEETFor se f ls ormto e FM 6-40; p olsonon gency s TRADOC.

BATTERY DATA MET ESSAGE

%100.3 I

LTYOForsY .1,2....... 9 2e,3) %..

( bS ... S. I', ..r:.i:a.Q.. I C)ot 9 . / f,INE.'R. MwuIwo EEor osu IR 1 s 0 -

ALT, OF .MOP' Z 2

4 s6twOCotCtIeNa. co A46r bE CA4 L.I4

MASON I~

l

011SFll

ALT OF M E T E T S A N N E C T VA S

ALTorBUSTIi MSpsAO COOC s

..... I . . . . .L______ 1(o.- f- .

MS P.. a T o-OUP a . --M ..rAlMS @6L 0307-A

WHO tM A N G 5 E FE TION

9 a law o r M isILI I",I mo ' *TI1 ~m

La# ' M0 RFI aA00 -- Ron?

.... t m , -IN,dop ::)

... . . T. . z2&. '_

,_NOT-AT

- .S 4 ( - -7 .a , )_- -9.1 IC"" a

COMP IT

ICHAA? OR COTPUTOFIMIN*OCoo*

_. _p.c . .79To _l5 L

SEEP 9 "0 --' Y P. - C . La . ' f SCY. .... . 4 ,) W 4 R::.+ TIO04"-~~d T$5........-0Ge,on$ p citmp Of

A" --I . ..... <.) a .. +.,-,.J ass: .ao an..--(

W-," , =1.A -A....ECTIONSA+

MET FUZE CIRECTION

AV 19A o.442250 /1MANCIC;us"D q336v 1,-. n.. 4 AAI /.o

....... __,.oo+ .-., / .9 o

EIGHT T :::'OTA0.5

M L

O L o E G+o - r 15c A [ -lAna/bLz/9o0

P-3

P.>

P)P)

DAFORM20 REPLACES OA FORMS6 15, 1 APR 67. WHICH IS OBSOLETE

Figure 10-34. Compi

FOLDOUT 10-33

eted subsequent met.

c. Enter the met line number and metmessage data. Since an adjusted quadrant isunknown, use the met line number from theconcurrent met. Record, as shown in figure10-33, the data from the met messageexample at the beginning of this discussion.Also enter wind speed in the wind componentblock. If height of target above gun haschanged from the concurrent met, determineand enter the value of comp range in the comprange block by using table B of the tabularfiring table. Enter the table with the chartrange expressed to the nearest 100 meters andthe met line number used.

d. Compute A h and height of target

above gun. Since the met station has movedand its altitude has changed, A h must becomputed. The height of target above gun(VI) has not changed (fig 10-33).

e. Compute chart direction of wind asshown in figure 10-34.

f. Enter table B and extract the data inthe same manner as in the concurrent met.

g. Enter table C and extract and recordthe data as shown in figure 10-34.

h. Enter table D and extract and recordthe corrections as shown in figure 10-34.

i. Enter table E and interpolate or extractthe correction to muzzle velocity forpropellant temperature and record as shownin figure 10-34.

j. Compute the corrected values fortemperature and density by adding thevalues from table D to the met values. Recordthe result as shown in figure 10-34.

k. Compute the entry range by adding thecomp range and chart values together.

1. Compute crosswind and range wind bymultiplying the crosswind and range windcomponents by the wind speed. Record theresults to the nearest knot as shown in figure10-34.

m. Compute variations from standard.Record the corrected values for range wind,air temperature, and air density in the METRANGE CORRECTION block. Computevariations from standard as shown in figure10-34.

10-34

+.

L



FM 6-40

n. Enter table F and determine the unitcorrections.

o. Enter table H and determine therotation correction for range.

p. Enter table I and determine therotation correction for azimuth.

q. Compute the met deflection correctionin the same manner as in the concurrent met.

r. Compute the new total deflectioncorrection by adding the position deflectioncorrection and the met deflection correction.

s. Compute the met range correction asshown in figure 10-34.

t. Compute the total range correction. To

determine a new total range correction,determine the AV range correction and addto the met range correction (fig 10-34.) First,determine the AV by adding the position VEto the current MVV for that charge and lot todetermine the velocity error. Add the VE tothe change to muzzle velocity for propellanttemperature. Convert the A V to a A V rangecorrection by multiplying A V by theappropriate MV unit correction factor. If AVis minus, use the decrease factor. If AV isplus, use the increase factor. Then add the AV range correction to the met rangecorrection. Express the total range correctionto the nearest 10 meters.

u. Compute the adjusted elevation byadding the total range correction to the chart

range. Set the MHL of the GFT over thisrange.

v. Enter variations from standard anddetermine values from table J (fig 10-34).Enter the variations from standard in theMET FUZE CORRECTION block, andextract the appropriate values. The entryargument for table J is the fuze settingcorresponding to the adjusted elevationexpressed to the nearest whole fuze settingincrement.

w. Compute the met fuze correction andthe total fuze correction. Determine the metfuze correction in the same manner as in theconcurrent met (fig 10-34). To determine atotal fuze correction, add the met fuzecorrection to the position fuze correction.

x. Determine the GFT setting. The newGFT setting is the same as the old one exceptfor a new adjusted time and elevation.Determine the GFT deflection correction bysubtracting drift corresponding to the newadjusted elevation from the new totaldeflection correction.

EXAMPLE:

GFT A: Chg 4, Lot XY, Rg 5140, El336, Ti18.9;Tot Df Corr: R3Drift ~ Ad] El 336 = L7GFT Df Corr R4

Section V

SUBSEQUENT MET APPLDCATHOHS

10-17. EIGHT-DIRECTIONMET

Certain combat conditions may require afiring unit to provide accurate artillerysupport throughout a 6,400-mil zone.Transfer limits define an area within whichregistration corrections are assumed to bevalid. These transfer limits place a severelimitation on a 6,400-mil firing capability.

Registration corrections may be obtained byconducting a registration in each 800-milsector of the unit's area of responsibility.Such registrations, however, would be costlyand would endanger unit survivability.Ballistic computers (BCS, FADAC, andTACFIRE) provide corrected firing datathroughout 6,400 mils. These computers canalso provide data for use in determining aGFT setting and a GFT deflection correction

10-35



FM 6-40

for each 800-mil segment of a unit's area ofresponsibilty. However, when BCS orFADAC is not available, a manual solutionfor determining corrections throughout 6,400mils must be used. The application of current

registration or met +VE corrections producesaccurate results within range and deflectiontransfer limits. The 6,400-mil capability canbe provided by conducting a registration orby calculating a GFT setting for each 800-milsector by use of the met + VE technique.

a. The eight-direction met procedureprovides corrections to range, deflection, andfuze setting to compensate for the effects ofballistic wind direction and velocity and forrotation of the earth throughout the firingunit's area of responsibility. When these

corrections are combined with knownposition corrections, lateral transfer limitscan be eliminated for ranges of 10,000 metersor less (fig 10-35). For ranges greater than10,000 meters, there will be areas between the800-mil segments that are not covered byvalid corrections, because the lateral transferlimits are valid 4,000 meters right and 4,000meters left of the battery registration point.

OCTANT VII5451 -

When needed, corrections must be computedby use of a met to a target to cover these areas.(Procedures for solving a met to a target arediscussed in paragraph 10-19.) Theeight-direction met technique consists of twosteps:

(1) Solution of a met messageconcurrent with a registration to determinethe position VE, position deflectioncorrection, and position fuze correction.

(2) Solution of a met message for other800-mil segments by use of the met + VEtechnique and the position VE, positiondeflection correction, and position fuzecorrection to determine the GFT settings forthose octants.

Note. The major change is the direction offire foreach octantand itseffecton windan drotation corrections.

b. Using the known data from paragraph10-16, the FDO decides to determine a GFTsetting for octant II, 800 mils to the right (fig10-36).

OCTANT III2251

r

Figure 10-35. Met octants.

\ 10-36



METDATA CORRECTION SHEETFoe use *4 IbiD form, SAD FM 6.40; pTopoNn oqSncy is TRAOOC.

BATTERY ATA MET MESSAGE

o .UPSA P 2,,Oa T_4 -Z__ O S,2

49A9. £ A CONNECTION .. C

2-55LT F U ST I

DOIGMT fPTARUET 0 CI 00.......... -UJ j C ...... 74~-2~"WINDCOMPONENTS ND DEFLECTION

WREN .DE9CTICOF IN 11 040 P c)A-a

IRECTIONf, No a.o

M A A P 0N- 16F P

U S E DEATA OC A zMOT * . 04OFUTATI OFWE

C NYDIO E~iowolac OMUATO coo.

P. .. .AUU...TUAC ; ,T6Zk Cl:DZ~A io3tD..AA CAACIV r +AR IVAUN

ItQ4 1 sIF S - - 0bL-' )- gf l7)j,T FAuE CORRECTION

_____342

-7-JL' WtW14'~ 0~01 ....

0Oc-T sFlAr

DAFO1 4200 <<,,,C .. ...L A

Figure 10-36. Eight-direction met.

FM 6-40

10-37

ALllT OF uARGETl

114116" OF 618IT. ...AE

T



FM 6-40

(1) Known or unchanged data fromconcurrent met are recorded.

(2) Target altitude is the same as thebattery altitude.

(3) Met line number is the same as thatin the concurrent met.

(4) The fuze setting corresponding tonew adjusted elevation yields the same entryargument for table J. This entry argumentmay change.

(5) GFT setting for octant II is asfollows:

GFT A: Chg 4, Lot XY, Rg 5140, El 342,Ti -19.3.GFT Df Corr = total - drift

R11 = R4 - L7

10-18. MET TO A MET CHECKGAGE POINT

a. When data from a registration and twomet + VE computations to met check gagepoints are known, a more accurate GFTsetting can be determined. When a three-plotGFT setting is constructed, it may be used forthe full range of the GFT without regard torange transfer limits. Solution of the met tothe met check gage point will yield a totalrange correction, a total deflection correction,and a total fuze correction at each met checkgage point range. The met check gage pointsselected should be the ones farthest away (inrange) from the registration point range thatare usable.

b. Using the data from the concurrentmet sample problem (para 10-12), the FDOdecides to

determine a multiplot GFT settingby using ranges 3730 (fig 10-37)and 5580 (fig10-38) and the original range to theregistration point.

(1) Target altitude is the same as thebattery altitude.

(2) Met line number is determined fromtable B.

(3) Figures 10-37 and 10-38 show thecompleted met forms.

(4) The GFT settings to the two metcheck gage points are as follows:

GFT A: Chg 4, Lot XY, Rg 3730, El 225,Ti 12.8GFT A:

Chg 4, Lot XY, Rg 5580, El 374,Ti 21.0

(5) The GFT sett ing from th eregistration is:

GFT A: Chg 4, Lot XY, Rg 5140, El 335,Ti 18.9

(6) The average GFT deflectioncorrection is R4: (R) + R5) + (R2) = R12 - 3=R4.

(7) The average total deflectioncorrection is L2: (L2)+ (R1)+ (4)= L5-3= L1.67

L2.(8) The multiplot GFT setting is applied

to the GFT.

10-19. MET TO A TARGETa. A met to a target must be completed if a

target appears in an area not covered by acurrent GFT etting. The manual solution fora nuclear mission may also require thesolution of a met to a target. A met to a targetis solved by using the same procedures asthose used in solving a subsequent met. Themet message line number is determined fromtable B by using chart range to the target andVI expressed to the nearest 100 meters. Thedirection of fire is the chart direction to thetarget.

b. Assume a target is to be engaged in anarea outside the octants for which GFTsettings have been determined. Chart data tothe target are as follows:

Target number

RangeDeflectionAltitude

AA7079

41003853345

(1) Data that are known or unchangedfrom the concurrent met (para 10-12) shouldbe recorded.

(2) The firing battery reports no changein propellant temperature.

(3) The met line number is determinedfrom table B.

10-38

I

0



[ METDATA ORRECTIONSHEETFr us. of hi. form, CR FM 6-40; prpaM a*CeyisCCCP RADaC.

SATTERY ATA MET MESSAGE

CC AC mIA C A0IZARA

* AA~rD3 CRGig

K S o d it LoMP.0 (..

A LTO TCTGEJ

FACIONCF OU I

CGRETDUE 160.4 S7c

C ~ 1 3&17i7RUILOOWIND OMPONENTS ANDDEFLECTION

RCWRNICCOWNOOCCU C L S C b & L-

CO CSOO T7ho.Ct:aLC oA.A

onO ETICAOFP fo Co.

NRA OD CO.R

MECT ANGE CORRECTION

KNOWN CANON No. U17NU

PRO9 NC ACTST N.MOg1 .Ac'410.

COMPUTYATION F YE

CPLf CACARETOCAMVTC flCu'pWN 4PC~

I I 'I C , I aC-CI ,EIL(C.

CTCINCGCCN-CV

~7j2.Pb~ZjL~j~j El T UCE CORRECTION

8 :1I , 0C :sI? - -C ., 2C-3-0I

3730 225 3.

_ 4 nQl '0111< 0

nn r) 0 C P ~ C

" 10.11.CTI... -0C

DA FC1M15iI qPCOo'MACIFDA~ 20REPLACESI

n ci

Figure 10-37. Met to a met check gage point-range 3730.

MET DATA CORRECTIONSHEETFo# use of +is lorm, see FM 6-40; ProPoneni agencY in TRADOC.

NATTERY DATA MET MESSAGE

c. GE Avj pt X-A, ING i.f,,19 -- t -f$$-Gf OCT. t

Sac, 1 -eNA TIME ^LT Nap s..z

ALT OF FTFIY;O 'N) 2-a 4; 15 1.LINE O ""1 11" EPEE . . * TcMP AIR OE.SIT

^LT Of MOP oj P,rVITR or jA 41 Is CORRECTION c- .4

1355VACRCCCC~~CI

ALT '*CCC)(or.0MS

Wmc.O.*j TO OF ."D WI D C m P E NT)ANDEORR ECT ION0

DIRECTIONCOMPUT TIONOP -A.E

C RCAPaor c"Nc.RHCT A

1"'P +8 I?--,ICC± 4=:Q. .5+~CICA-. k.-I,,IP4

£15..A~~~YCL 2 .L6 .FZI.MTPUEORRECTION 94

6v 0SiO L W 11

f..,r1.0 Ctf-

- 12.. 1214

Iue103. e ta mtchc0ggpitraneo580

10-39

FM 6

10-39 FO

Ell

ff

I

-10 --

jFgWW-j lcm.mr mc.

I

L,

I

-I

co.llc 11TO It

DA FORINA 15, 1 APR 6 7 . V041CH IS OBSOLETE



FM 6-40

FOLDOUT 10-39

I I-CL 1 ..14 -q

PJEUE CORRECTION

534

D k A , ?M4 2 0 0

P L ( IIF 11 I IAl-llwICI$QTL E

Figure 10-39. Met to a arget.

10-40

METDATA CORRECTION SHEETF., voDNof t oIN II...FM 6.40; pr~pDI,%g i.. TRACOC.

BATTERY ATAMET MESSAGE

MONT C- .-- A ~.. l. 1CT..TOC ..

ALTSOcWOOto Lt{.o0,

CLO I CIO AN N

RINLCTPOONF AN D E L E C I O

a* aAN ID I

NELTANGECORRCTIO

NEND cujA4. to~WIN CMPNEN$ N D D E F E C I O

DCOMPUTATIONFO.aYE

DRIN or 0NIMN , w ~ ~ u z



FM 6-40

(4) The unit will fire charge 4GB, fuzetime (M577), shell DPICM.

(5) The azimuth to the target isdetermined as follows:

Common deflection 3200Chart deflectionto target 3853Deflectionincreases 653(azimuth decreases 653)Azimuth of lay 6350Change in azimuth -653Azimuth to target 5697

(6) Position fuze correction is 0 for theM577 fuze, since it is not similar to the M582fuze used in registration.

(7) The completed met to a target isshown in figure 10-39.

(8) Firing data determined (for batterycenter) (fig 10-40) are as follows:

Time 15.8Deflection 3851Quadrant elevation 328

RECORD OF FIRE

CALLOR iRE s /s

ObevrAF~EqS/ Sl Tocr /4Grid: /K

Polor:Dir Dis U/D VA /0- 20/Shift Dir U/C

F S 4 Si 10 lOt Si MOB orr

FIRE lDER TI,, C-k/-0C .., ,f Corr n, -o-. ,

INITIALFIRECOMMANDS V MF ioc4on(tt Dl'35 ' (7 r)Splensir AC Sb- toLt k 4 C Ig Fi Ti Df " 8

F O R EPACE DAtc I 4 5 4 1 M T76WHCHI OSOLT in Ef O fFIS OR SEE M 4

S oct Priorit Firing SUBSEQUENTIRE OMMANDSFig u rnit M e tair o. ,v9 Ha M. h, FS T I Chart iOfCorr CH Chart MOBl Si - ' Type

,Sh,Z Corr Cho, F1 Corr Of i Fired I 9 Cor of Exl

,:: :: .............. ...............:i:ii: :::::i~:: . iii:iiiiil~ii:ii.~~ ~ ~ ~ ~ ~ ~~...... ........'o6, :T c i O I E : F . : - - CAr

F O * M * I P ~ ~ i S ii F* A SO I I~ 6,Wllia ISo~so m Fo uslof.TI...*.......-4., 4LT VM V504.. ... ~iW..... S__ mlllm I I . I . m l m . i m m m m . i.

Figue IO40.l o atame -- PIC mision

10-41



FM 6-40

Section VI

MET PLUS VELOCITY ERROR

10-20. APPLICATION OFVELOCITY ERROR

It is undesirable to register each time thereis a significant change in weather. To keeprange corrections current in such situations,a technique called met + VE is used. Themajor change in corrections is due to changesin met condit ions and propellanttemperature. A new met message will providecurrent met conditions. Velocity error is

virtually constant. A total range correction isdetermined by adding current met rangecorrections to A V range correctionsdetermined from the position average VE inmeters per second and current corrections toMV for propellant temperature. The totalrange correction is applied to the GFT settingrange in the same manner as a rangecorrection determined from a registration.

10-21. MANUAL COMPUTA-TION OF A GFTSETTING FOR ANUNREGISTEREDCHARGE

The sample problem below describes themanual computation of a GFT setting for anunregistered charge. The following situationexists: A registration has been conductedfiring charge 4GB, propellant lot Y. Aconcurrent met has been solved. The FDCdesires a GFT setting for charge 5GB, lot Y.An MVV for lot Y of -1.4 meters per secondwas measured for the adjusting piece duringthe charge 4GB registration.

a. Determine the range to a met checkgage point on the charge 4GB graphicalfiring table. This will be used as the chartrange on the met data correction sheet. Theentry range will be the met check gage pointrange expressed to the nearest 100 meters.

b. Compute the GFT deflection correctionas follows:

(1) Compute the met deflectioncorrection by use of the met data correctionsheet.

(2) Add the position deflectioncorrection determined from the charge 4GB,lot Y, concurrent met to the newly computedmet deflection correction for charge 5GB, lotY. The sum is the total deflection correctionfor charge 5GB, lot Y.

Note. The position deflection correctiongenerally accounts for errors in survey andchart construction. These errors areindependent of charge in that they remainconstant regardless of the charge fired.Therefore, it is valid to apply a positiondeflection correction determined for onecharge to other charges.

(3) Subtract the drift correctioncorresponding to the adjusted elevation forcharge 5GB from the total deflectioncorrection. The remainder is the GFTdeflection correction for charge 5GB, lot Y.

c. Compute total range correction andadjusted elevation as follows:

(1) Remember that VE is caused byfactors such as chart errors, survey, tubewear, and projectile ballistic coefficient.From this statement, it can be concluded thatthe position VE is made up of the MVV thatcan be measured and the other factors thatcan be determined only by firing.

Note. Velocity errors caused by survey

and chart errors are charge independentand, therefore, can be transferred to othercharges. Muzzle velocity variations can betransferred to all charges within the samecharge group and lot (chap 13).

(2) Transfer the position VE andcharge 4 MVV, add them, and then usesum as the charge 5GB velocity error.

thethe

(3) Now add the MV correction forpropellant temperature to yield the charge5GB AV.

14 n-01"7



FM 6-40

(4) Multiply AV by the charge 5GB MVcorrection factor to determine the A V rangecorrection.

(5) Add the computed met rangecorrection for charge 5GB to the AV rangecorrection to determine the total rangecorrection.

(6) Add the total range correction to therange of the met check gage point todetermine the range corresponding toadjusted elevation.

(7) Set the adjusted range under theMHL of the GFT, and read the adjustedelevation for charge 5GB.

d. Compute the total fuze correction as

follows:(1) Compute the fuze correction.

(2) Add the met fuze correction to theposition fuze correction determined for thecharge 4GB concurrent met. The sum is thetotal fuze correction, which is applied to thefuze setting corresponding to the adjustedelevation to determine the adjusted fuzesetting for the GFT setting for charge 5GB.

10-43





FM 6-40

f. Calibration-the determination of anMVV for every weapon in the firing unit. In acalibration, all weapons fire the same or anadjacent charge of a propellant and projectilelot.

g. P r o p e l l a n t L o t - a group ofpropellants made by the same manufacturerat the same location with the sameingredients. Individual propellant canisterswithin the same lot will develop the same MVwhen fired with the same projectile family.

h. Preferred Charges-the chargespreferred for measuring muzzle velocities foreach propellant type. These charges produceconsistent, predictable muzzle velocities. TheMVVs they produce will not vary more than+1.5 meters per second. Therefore, the MVVdetermined for one charge of the propellanttype will be similar (within ±1.5 meters persecond) to another charge of the samepropellant type and lot. Preferred charges areidentified in table 11-2.

Table 11-2. Preferred charges.

1. Measured Muzzle Velocity-cali-brated MV from the first-lot calibrationentered on the muzzle velocity record.

11-2. CALIBRATIONa. Muzzle Velocity Data. The M90

velocimeter makes current MV dataavailable to the FDC for use withconcurrent/subsequent mets and for positioncorrections. Use of the M90 velocimeter andthe proper management and recording ofdata are critical in the use of these data. Thefollowing discussion outlines MVVmanagement procedures.

b. Muzzle Velocity Logbook.(1) Sectioning the logbook. The FDO

sections the major portions of his logbook bythe projectile families (fig 11-1).

Figure 11-1. Muzzle velocity logbook sectionedby projectile family.

(2) Tabbing the logbook. Eachsection (projectile family) of the MV logbookis tabbed with all possible powder models (fig11-2). After the MV logbook has beensectioned and tabbed, it will be ready forentry of data.

i. Inferred Calibration-the etermin-ation of MVV data for all firing unit weaponsby mathematical procedures.

j. Readout Average-the average M90readout of a group of projectiles.

k. Calibrated Muzzle Velocity-theMV of a group of projectiles when corrected tostandard conditions by applying correctionsfor propellant temperature and projectileweight to the measured muzzle velocity.

Figure 11-2. Muzzle velocity logbook tabbed bypowder model.

-2

0



FM 6-40

c. Calibration.

(1) Determinat ion of data. Thehowitzer section mounts the M90 velocimeter.The executive officer directs the velocimeteroperator to record all administrative data onDA Form 4982-1-R (M90 Velocimeter WorkSheet) (fig 11-3 and app J). The M90 readout

values are recorded on the bottom portion ofthe form. Normally, data from six usablerounds are used to maximize accuracy. Thesesix rounds can be from any fire missionreceived by the battery. Specially conducted

calibration missions or firing sessions are notrequired. Fewer than six rounds can be firedin a calibration, or fewer than six rounds may

Figure 11-3. Determining M90 readout values on DA Form 4982-1-R.

11-3



FM 6-40

be determined to be usable rounds. In thesesituations, the calibration validity is reducedin the same manner the validity of aregistration is reduced when fewer than thenormal amount of rounds are fired. Refer totable 12-1 for validity information and theeffect of reduced rounds on the calibrationdata. Powder temperature differencesbetween rounds decrease the validity of thecalibration. To reduce powder temperaturechanges from round to round, use goodpropellant handling and storing proceduresin the firing battery, and fire all rounds to bemeasured for a calibration within a20-minute time period. Follow theseprocedures for the calibration of all weapons.When the administrative data and the M90velocimeter readout

data are completed onthe form for all guns, give the form to the firedirection center.

(2) Determination of M90 readoutaverage. The FDO inspects the readoutvalues for all rounds and deletes any invalid

readout values (errors). The FDC thendetermines the readout average for the usablerounds by adding all usable readout valuesand dividing the sum by the number of usable

readouts. The readout average is the actualspeed, in meters per second, of the average ofthe usable projectiles as they left the tube.This value includes the effects ofnonstandard propellant temperature andprojectile weight.

(3) Correction to standard. The M90velocimeter readout is not used in its presentform, because it contains the effects ofprojectile weight and propellant temperatureon the muzzle velocity. The MVV determinedfrom the readout average can be used onlyafter it is corrected to standard projectileweight and standard propellant temperature.The corrections for projectile weight andpropellant temperature are applied byextracting the value for the MV correctionfrom the appropriate table in MVCT-M90-1correction tables (fig 11-4) and applying this

Figure 11-4. Extract of MVCT-M90-1 tables.

11-4

MVCT M90-1CHARGE HOWITZER, 155MM,. MI09AI AND M198

4G PROJ. HE. M107CORRECTIONS TO MUZZLE VELOCITY IN METERS PER SECOND

TO COMPENSATE FOR DIFFERENCES INPROJECTILE WEIGHT AND PROPELLANT TEMPERATURE

TEMPERATURE PROJECTILE WEIGHT IN SQUARES TEMPERATUREGF OF

PROPELLANT PROPELLANT

DEGREES F 1 SQ 2 SQ 3 SQ 4 SQ 5 SQ 6 SQ 7 SQ DEGREES C

-40 1.2 2.9 4.6 6.3 6.0 5.7 11.4 -40.0-30 .6 2.3 4.0 5.7 7.4 9.1 10. -34.4-20 .1 1.6 3.5 5.2 6.9 8.6 10.3 -28.9-10 -.5 1.2 2.9 4.6 6.3 6.0 9.7 -23.3

0 -i.1 .6 2.3 4.C 5.7 7.4 9.2 -17.8

10 -1.7 .0 1.7 3.4 5.2 6.9 8.6 -12.220 -2.3 -.6 1.2 2.9 4.6 6.3 8.C -t.730 -2.9 -1.1 .6 2.3 4.0 5.7 7.5 -1.140 -3.4 -1.7 .0 1.7 3.4 5.2 6.5 4.4

50 -4.0 -2.3 -. 6 1.1 2.9 4.6 6.3 10.0

60 -4.6 -2.9 -1.2 .6 2.3 4.0 5.8 15.670 -5.2 -3.5 -1.7 0.0 1.7 3.5 5.2 21.180 -5.8 -4.0 -2.3 -.6 1.2 2.9 4.6 26.790 -6.4 -4.6 -2.9 -1.1 .6 2.3 4.1 32.2

100 -7.0 -5.2 -3.5 -1.7 .0 1.8 3,5 37.8

110 -7.5 -5.8 -4.0 -2.3 -. 6 1.2 2.g 43.3120 -8.1 -6.4 -4.6 -2.9 -1.1 .6 2.4 48.9130 -8.7 -7.0 -5.2 -3.4 -1.7 *1 1.8 54.4

.. . . .. . . . .. . .



value to the readout average. The correctiontables contain data to reflect what thereadout average would have been if thereading had been determined with a4-square-weight projectile and a propellanttemperature of 700 -F. Enter MVCT-M90-1with the appropriate weapon system andprojectile family. Locate the page containingthe table for the same charge fired in thecalibration. Enter the table with thetemperature of the propellant at the time ofthe calibration and the weight of theprojectile fired in the calibration. Interpolatethe value to correct the readout average tostandard, and apply that value to the readoutaverage.

EXAMPLE:Given:

Propellant emperature: +460FProjectile weight: 3 squares

Readout average: 559.5 m/s

MVCT-M90-1 extract (fig 11-5)Determine the calibrated muzzle velocity.

1. Enter MVCT-M90-1 table usingpropellant temperature to nearest 1' F andprojectile weight to nearest listed value asentry arguments. (Interpolation f data romtables will be required.)

2. The value extracted from the table is thecorrection actor which, when applied to thereadout average, corrects the data to reflectthe standard propellant temperature (700 F)and the standard projectile weight (4squares). Since interpolation will berequired, extract the range of values that

contains the correction actor.

From table:

F -400

60

460100

500

0 m/ s

xj

-0.6 m/ s

-0.6 m/s

6/10 =X/-0.6lox = -3.6X= -0.36 ,Z -0.4 m/ s0 m/s + (-0.4) m/s = -0.4 m/s

3. Determine he calibrated muzzle velocityby adding the MVCT-M90-1 correctionfactor determined in step 2 to the readoutaverage.

Readout averageMVCT-M90-1 corr factorCalibrated muzzle velocity

317.1 m/s+ (-0.4) m/s

316.7 m/s

(4) Use of muzzle velocity record

form. DA Form 4982-R (Muzzle VelocityRecord) (fig 11-5 and app J) is the record of acalibration or a partial calibration. The topportion of the form (FIRST LOT CALIBRA-TION) is used to determine the weapon MV Vand MV for a specific charge. The bottomportion of the form (SECOND LOTCALIBRATION/INFERENCE) is used toinfer MVV data for a second lot ofpropellant/ammunition.

(5) Determination of first-lot pieceMVV. From the TFT, extract the standardMV for the charge fired in the calibration.Compare the calibrated MV to the standardMV to yield the MVV for each piece.

(6) Determination of the weaponmuzzle velocity. Apply the piece MVV tothe standard MV to determine the weaponMV for that powder model. Now enter themuzzle velocity record in the muzzle velocitylogbook in the appropriate shell family andpowder model for future reference. Theappropriate data are entered in the computer

system available to the battery and are madeavailable to the executive officer for entry onDA Form 2408-4 (Weapon Record Data). If acomputer system is not available, use DAForm 4758 (Section Chief's Card,Computation Work Sheet).

(7) Use of MVV. To determine positionVE, subtract the MVV from the VEdetermined in a concurrent met. A positionVE can be used in a subsequent met todetermine the VE by adding the position VEto any MVV from any powder model (POS VE+ MVV = VE). Muzzle velocity variation isalso used to determine a comparative MV Vwith deliberate or hasty position corrections.

FM

MUZZLE VELOCITY RECORD DATE POWDER GROUP

For use of this orm, see FM 6-.40;, he proponent agenc is TRADOC 122 MhY M + AZ

FIRST LOT CALIBRiATION

SHELL/FAMILYFIRST POWDER LOT NUMBER

/wA - 2 3 - 5 7 6 /GUN NUMBER/CHARGE FIRED

ITEMS 1/ 2/ 3/ 4/7 S/ 6/

I, WEAPON BUMPER NUMBER A-22 A-24.A-26 A-2S A-30 A-32

2. WEAPON TUBE NUMBER 1/22 223-3 3531 4L 4-55 5566 G(o77

3. FIRST LOT CHARGE STANDARD MUZZLE VELOCITY 565.4 56 .4 566J '3& 'SG. 5 6 . , 4 565.4

4. CALIBRATED MUZZLE VELOCITY 562.9 562.8 S3.9 563.2 563.0 565.35. FIRST LOT PIECE MUZZLE VELOCITYVARIATION -2-5 -2 6 - /- 5 -2.2-. -2- -4-0.I

SECOND LOT CALIBRATIONI /INFERENCE

SHELL/FAMILY DE POWDER GROUPGUN NUMBER/CHARGE FIRED

ITEMS I 21f 3/ 4/7 6/

6. SECOND LOT CHARGE STANDARD MUZZLEVELOCITY56 4_

7. SECOND LOT CALIBRATED MUZZLEVELOCITY 562.6

S. FIRST OTPIECEMUZZLE ELOCITY ARIATION5) -2 29. CHANGE IN MUZZLE VELOCTY VARIATION

10. FIRST LOT PIECE MUZZLE VELOCITY VARIATION -2.215)

11. CHANGE IN MUZZLE VELOCITY VARIATION19) 0-7

12. SECOND LOTINFERRED FIRING UNIT MUZZLE

VELOCITY VARIATIONS6 .13. SECOND OTSTANDARD UZZLE ELOCITY LL't

14. SECOND LOT CALIBRATED MUZZLEVELOCITY

15. SECOND LOT PIECE MUZZLE VELOCITYVARIATION

IlA CA n A O 9 D e CA

Figure 11-5.

LUIION OF MAY 1981 IS OBSOLETE

Muzzle velo ity record.

11-5 11-5 FOL

• ,pA , r . m i ~ v ru ,s.-n Ortl- 0"4





FM 6-40

Chapter 12

f all conditions of materiel, posi-tion, and weather are standard,

firing a cannon at a particular elevationwill cause the projectile to travel therange shown in the firing tablecorresponding to that elevation. Seefigure 10-1 for a list of standardconditions. Similarly, if the properdeflection is set on the weapon, theprojectile will burst on the gun-targetline. However, standard conditions ofmateriel, position, and weather do notexist simultaneously. Thus, th e

projectile will rarely hit the target whenfired with standard data for the rangeand deflection.

Inaccurate surveys, inaccurate firing

charts, and nonstandard conditions ofmateriel, position, and the atmospherewill contribute errors. The number ofmeters short or over, left or right of thetarget is the combined effect of theseerrors. The magnitude of the cumulativeerrors and the corrections for thoseerrors can be determined by registra-tion.

SECTION ICHARACTERISTICS

12-1. TYPES OFREGISTRATIONS

The two types of registrations are precisionand HB/MPI. In the two categories, there arealternative methods of registering that maybe more suitable to the current tactical

situation.a. Precis ion Regis t ra t ion . The

precision registration is a technique used fordetermining, by adjustment, the firing datathat will place the MPI of a group of roundson a point of known location. This point iscalled a registration point.

b. H B / M P I Registration. The HBand MPI registrations determine the meanburst location (MBL) of a group of roundsfired with a single set of firing data.

c. Alternate Registration Types.

(1) Radar-observed registration.The radar registration is a form of theHB/MPI registration and is thoroughlydiscussed in the latter part of this chapter.

(2) Abbreviated registration. Any

registration that is conducted by using fewerusable rounds than recommended by theprecision HB/MPI techniques is anabbreviated registration. The use of fewerrounds results in the degradation ofregistration correction data. However, theuse of fewer rounds to determine the MBL orthe use of a larger "acceptance box" (forexample, 2 PEs rather than 1 PE from theMPI) is acceptable if the decreased accuracyis acceptable to the commander and if it is forthe accomplishment of the mission.

12-1



FM 6-40

(a) Abbreviated HB/MPI registra-tion. An abbreviated HB/MPI registration isconducted exactly like an HB/MPIregistration, except that as few as one, two, orthree rounds are actually fired.

(b) Met+VE and check round(s). Thisform of abbreviated registration requires the

solution of a subsequent met to an accuratelylocated target and determines adjusted databy adjusting a round(s) fired by use of the met+ VE firing data. Corrections are determinedon the basis of observer refinement.

(c) Abbreviated G/VLLD registra-tion. The abbreviated G/VLLD registrationdetermines adjusted data by comparing thetarget location with the location of the lasedround.

(d) Adjust fire missions. Any adjustfire mission conducted on an accuratelylocated target or by an accurately locatedobserver by use of a G/VLLD can be used toimprove firing accuracy by determiningregistration corrections on the basis of theobserver adjustments. In this case,refinement data must be sent by the observer.The validity of the GFT setting is directlyproportional to the accuracy of the targetlocation.

Note. Use of the G/VLLD enables anobserver to accurately locate a target toregistration-required ccuracy.

(3) Offset registration. A platoon oroffset position as much as 1,000 to 2,000meters away from the battery center can beused to conduct a registration. The GFTsetting determined from the offset position isassumed to be valid for the primary positionif common survey and common direction

exist between the two positions. Aregistration from a flank platoon may reducethe vulnerability of the battery.

(4) To the rear registration.

(a) Registering to the rear (or at someazimuth significantly different from theprimary azimuth of fire) results in a GFTsetting that does not include the primaryazimuth of fire within its deflection transferlimits.

(b) To derive a GFT setting for theprimary azimuth of lay, apply eight-direction met techniques as follows:

* Determine position corrections byworking a concurrent met for theregistration

azimuth.* Using subsequent met techniques,

determine total corrections (in thedirection of the azimuth of lay) byreworking the met. See chapter 10 for adiscussion of the eight-direction mettechnique.

12-2. ASSURANCE TABLESA registration conducted with fewer rounds

than recommended will degrade the accuracyof the determined corrections. Accuracydecreases as fewer rounds are used. Table12-1 lists the percentage of probability thatthe mean location of a particular number ofrounds is within 1 or 2 probable errors inrange of the actual mean point of impact. Asmore rounds are fired, the MPI is moreaccurately located. If the tactical situationdictates that registrations be abbreviated,the assurance received from a fullregistration may have to be reduced.

Table 12-1. Assurance of registration validity.

12-2



FM 6-40

12-3. WHEN TO CONDUCTREGISTRATIONS

. a. A mission conducted only for thepurpose of registering does not cause anydamage to the enemy. It does, however,expose the firing unit to enemy targetacquisition devices. In addition, missionsconducted solely for the purpose ofregistering require additional ammunitionand time. Therefore,' when possible,registration missions should be integratedinto other missions, especially when theobserver is equipped with a G/VLLD (app K).

b. Computer-derived GFT settings or met+ VE GFT settings should be used whenaccurate MVVs, met data, and survey areavailable. The amount of correctionsnecessary to adjust onto a target will beminimal and can most likely be accounted for

in the observer's first adjustment. Firing twocheck rounds for an inferred GFT setting canbe an abbreviated registration. Anyrefinement sent by the observer should beused to adjust the GFT setting and computerresiduals.

c. Registrations (fig 12-1) are notnecessary if you-

(1) Have confidence in weapon locationand directional control.

(2) Have confidence in met.

(3) Have confidence in muzzle velocity.

(4) Have a valid derived GFT setting.

d. The accuracy gained by conducting amission solely for registering should beweighed carefully against the vulnerability.

to enemy detection andagainst the

expenditure of ammunition and time.

DO YOU HAVE CONFIDENCE IN:

WEAPON LOCATIONAND DIRECTION?

NO

IS THE ACCURACY GAINEDBY REGISTRATION WORTH

THE VULNERABILITYTOENEMY DETECTION OR THE

AMMUNITIONAND TIMEEXPENDED?

DETERMINE FIRINGCORRECTIONS FROM

MET + VE COMPUTATIONS(SEE PARAGRAPH 12-12).

YES > DETERMINE FIRINGCORRECTIONS FROM A

REGISTRATION.

NO*

SHOOT SUBSEQUENTMISSIONS USINGOBSERVED FIRES

(ADJUST FIRE).

SHOOT SUBSEQUENTUNOBSERVED MISSIONS

WITH BESTAVAILABLE DATA.

Figure 12-1. Registrations.

12-3



FM 6-40

Section IIPRECSD IEGDSW&TDAThS

12-4.DEFINITEON ANDOBJECTIVE

a. Definition. Precision registration isa technique that requires an observer toadjust a group of rounds fired from-the samegun so that their mean point of impact occursat a point of known location. The point ofknown location is called a registration point.Registration points should be small, hardtargets that are easily identified, immobile,accurately located, and not likely to becompletely destroyed if hit. Registrationpoints should be surveyed points,

and theirlocations should be provided by a target areasurvey of the intended zone of operations. If atarget area survey has not been conducted,registration points can be selected andlocated by the forward observer.

b. Objective. The observer's objectivein a precision registration is to obtainspottings of two OVERS and two SHORTSalong the observer-target line from roundsfired with the same data or from rounds firedwith data 25 meters apart (50 meters apartwhen PER is greater than or equal to 25meters). This normally requires the spottingsof four separate rounds. However, aTARGET HIT or RANGE CORRECT willbe spotted by the observer as both an OVERand a SHORT. The objective of the timeportion of the registration is to correct themean height of burst of four rounds fired withthe same data to 20 meters above theregistration point. The FDC's objective in aprecision registration is to determinecorrections to firing data on the basis of theobserver's corrections.

12-5. ENITATIONa. The decision to register is based on the

considerations in section I. After the decisionto register has been made, the FDOannounces a fire order. As in all fire orders,the FDO tells the FDC, clearly and concisely,how to conduct the registration according tounit SOP; for example, PRECISION

REGISTRATION, NUMBER 4, 1ROUND, LOT XY, CHARGE 4, QUICKAND TIME. In this example, PRECISIONREGISTRATION tells the FDC the type ofmission to be fired. QUICK AND TIME tellsthe FDC the correction to be determined forboth quick and time fuzes. The registeringpiece is selected as the piece closest to theGBC and by its average shooting strength; inthis case, number 4 firing one round. If thereis more than one registration point availableor if a second lot is to be registered, thatinformation is also specified in the fire order;for example, PRECISION REGISTRA-TION, REGISTRATION NUMBER 4,1ROUND, CHARGE 4, QUICK ANDTIME, REGISTRATION POINT 1 orPRECISION REGISTRATION NUM-BER 4,1 ROUND, LOT XY, CHARGE 4,QUICK AND TIME, LOTS X AND W.

b. When the RATELO hears the fireorder, he will send a message to observer toalert the observer. C8T16, THIS IS C8T23,REGISTER ON REGISTRATIONPOINT 1, QUICK AND TIME. OVER.The registration point is always specified

tothe observer. The range probable error is alsoannounced in the message to observer whenit is greater than 25 meters. See FM 6-30.

c. Digital transmission procedures arediscussed in the DMD and BCS operator'smanuals.

12-6. IMPACT PORTION OFTHE REGISTRATION

a. Fire direction procedures for theimpact portion of the registration areidentical to those for any adjust fire mission.All corrections are entered into the computer,entered on the calculator, or plotted on thefiring chart. Data are computed andtransmitted to the adjusting piece.

b. The firing data corresponding tostandard conditions (chart data) whencompared to the firing data with observer

12-4





FM~ 6-40

12-7 IREGESTEIEING PEfECEDIOPLACEMENT

a. When the registering piece is not overbattery center, the chart range measuredfrom battery center is not the range actuallyachieved. With the registering piece behindthe battery center, the achieved range isgreater than the chart range. The differencebetween chart range and achieved rangemust be taken into account when using theresults of the registration as the basis for aGFT setting.

b. When the registering piece is left orright of battery center, the correctiondeflection (circled on the record of fire) is notthe adjusted deflection.

c. Assume the registration usedinprevious paragraphs was conducted and the

registering piece was not over battery center.The steps to account for piece displacementare shown on section I of DA Form 4757 (fig12-3).

(1) Determine the achieved range.

(a) Enter the chart range in M of theregistration computation section.

(b )_En te r the piece displacement(B20) in Mt.

(c) Add or subtract (as indicated bythe displacement forward or back) the piece

displacement to the initial chart range. Theresult is the achieved range (the range thatthe projectile actually traveled). Enter theresult in Pl.

(d) Now use the achieved rangeinstead of the initial chart range indetermining registration corrections.

(2) Determine the adjusted deflection.

(a) Enter the correct deflection(circled on the record of fire) in .-J.

(b) Enter the lateral displacement(L130) in [J, and use the previouslycomputed achieved range to convert thedisplacement in meters to a correction inmils.

(c) Using the GST (C- and D-scalesand M-gage point), divide the lateraldisplacement by the achieved range inthousands of meters and record the result in111(130 meters "±5.09 L26).

(d) Add the corrected deflect*i(1)to the piece displacement correction 8). Theresult is the adjusted deflection (W).

12-Oo T I E PORTION OF JHEREGESTRATHION

a. The time portion of the registration canbegin when the observer requests fuze time(fig 12-4).

Figure 12-3. Registering piece displacement.

12-6

00



FM 6-40

PRIEC. REG.. G'TA RECORD Of FIRE

CALL B-------- -PT2 3"7 G T L LA .-marver -3Al/FPU/IS/ S TV BTRzY 3 5 3 DP L7 100/R

GM:7 :J IV + 21 L11 /R

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Figure1 2-4 Precision registratnE-qTuRicCO knTdTION I

.. ....... 1 4 0REGISTERING PIECE ISPLACEMENT ORRECTION 1

2 REGISTERING IECE ISPLACEMENTtF 8"10 c OMETERSi 8 ] (L" I t MIL)

REGISTERI G PIECE OISPLACEMENT ORRECTION 10 CHART EFLECTION a $s 11MILi

4 LATERAL ISPLACEMENT L RI 101TES tl TOTAL EFLECTION ORRE TiON "9, 1d lL.0 5, EERi1 IMILi

ACHIEVEORNGE()IIO METERS| I - ADJUSTED LEVATIONi L).. 1M l

6 REGISTERINGIECEISPLACEMENTORRECTION 13 ,APHICALN TABLEGFTI n4[ - E0 I L- R . . I MIUl DEFLECTION ORRECTION If 12'.' (I MILl

GFT ~nIG {MNUA METOD)DEFLECTION CORRECTION

12-7





FM 6-40

REICORD OF llIRlCAL" I[ ALT W CPT2.1( GFTL-reL .,1

O k:D.. iI D VA i L

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. . .

OC 4504RIPLACES A FORM 504, 1 MAY 16 , WNICH OSOLEM THUSE OF THIS ORM, EE M -

1111 MlIT AGENCY IRAI

SECTION 1I REGISTRM N COMPUTATION

ACHIEVED ANGE

I CHIEVERANGE t[ ])O M E T E R S i

2 REGISTERING IECE ISPLACEMEN T ORR1CTIN

1~ ~ ~ ~ ~0 1T1,N,"0 i5METERS)

REGISTERINGGPIECEISPLACEMENT ORRECTION

4 ,ATRA ISPL E ENOR) 15.....

DEFLECTION ORRECTION

7 CORRECTEDVFLECTIONREGISTRATION, ) 1 MILI

REGISTLMGPIECE ISPLACEMENT ORRECTION MILl

9 ADJUSTED EFLECTION) Efl 1 0 MILl

10 CHART EFLECTION 1M~

TI TOTAL E L CTON CORRECTION_]I(L - B -4LRt--IIMDRIFT ORRECTION

T I-ADJUSTED ELEVATIONI W . 7I MILl

13 GRAPHICAL IRING ABLE GFT)DEFLECTION ORRECTION I ; ;12

RECORD A F4IECALLOR iRE 7 370F r1 A - .

Ob SM/I AF/FFE/hS/ Tvt 35Ow lOGild:

$___loom_

FEDrCr Cis U/b VA vtShift ftID ..../201

Si+10 1.0Si HogRCs

FREORCER A88 _fkRSAc(D.1T .f Co L-/1 SiINITIAL IRECOMMANDSM F S R

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QAAI.......-- ~ ~ .uTot.Lowiwe Uw SUIQiN1IRECatANa

FORM all N e RA DA F S 1MYTWiCh SOfoCTHIrtSFOOiRM SEEM6xp0TFCO hi z Corr I to Corr +5)

SECTIN I.GISTATION COMPTATIO

3.. A R3 9DI3I...............

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ACHIEVEDRANGE DELECTIONrORRECTIO

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REGISERINPIEE DISLACEENTRRECIONy use oALIRNGTEG /VLLD

12-9 F

' :PJ 'm j ""I ....... ..... i.. ...GIFT ETTING MANUAL METHODI

DEFLECTION ORRECTION

1 GFT CHARG LOT y RANG ELEVATION " TIME TOTAL GFT

I GFT __ CHARGE L ILOT _ " |RANGE _ _ LEvatiOn T-•.AME _

,- GFT CAGE .. LOT RANGEEVAI ON TI E ' 1 "

Figure 12-5. Multilot precision registration.

12-9

I.

I-MIU



FM 6-40

12-12. MET + VE WITH ACHECK ROUND

Met + VE with a check round is anabbreviated form of a precision registrationin which adjusted data are determined withone or more rounds.

a. The first step of this procedure is toobtain firing data for the round(s) to be firedby solving a met to target (chap 10).

b. After the round has been fired and theobserver's refinement has been obtained,determine the adjusted data by plotting therefinement and determining data to thatpoint. Total corrections and the GFT settingare obtained in the same manner

as in aprecision regis t ra t ion-by comparing''chart" to "adjusted" and compensating forany piece displacement.

Section IIIHB/MPI REGISTRATIONS

12-13. OBJECTIVEa. When it is necessary to register, clearly

defined and accurately located registrationpoints may be limited or not available. Densevegetation or ground fog may prevent theobservers from seeing the ground. At night,the adjustment of fire on a registration pointis impossible without some type ofillumination. The high-burst or mean-point-of-impact registrations overcome theseproblems.

b. In both the HB and the MP Iregistrations, a number of rounds (usuallysix) are fired with the same set of firing data.These rounds are observed by two observersin surveyed positions, usually designated 01and 02, who can measure the direction toeach bursting round. The MBL is determinedand plotted on the basis of the observer'saverage directions. Chart data are thendetermined and compared to the adjusteddata that were fired.

c. The HB registration is fired by use oftime-fuzed rounds and offers an advantage

over the MPI by allowing the FDC todetermine a fuze correction for futuremissions. The high burst is also easier toobserve, especially at night, and registrationcorrections may be determined in areaswhere the observers cannot see the ground.

d. If the unit can use G/VLLD-equippedobservers, the HB/MPI registration can beaccomplished with one observer duringwartime or with two observers duringpeacetime. Laser safety requirements forpeacetime may prohibit G/VLLD live lasingabove the skyline. The G/VLLD registra-tion with one observer is handled as a radarregistration in BCS or FADAC, because theobserver can provide burst grid and altitudewhen equipped with the FIST digitalmessage device. In peacetime, two observersequipped with laser-safe G/VLLDs (shortingplugs installed) could provide azimuth andvertical angle information to the firedirection center. This registration iscomputed as an HB/MPI registration byusing two observers. If no G/VLLD observersare available, observers equipped withaiming circles or battery commanderperiscopes can be used.

FOLDOUT 12-9 12-10



FM 6-40

e. The requirement for surveyed observerlocations is the primary limitation of the HB

and MPI registrations.

f. There are six basic steps in an HB/MPI

registration.(1) Select an orienting point.

(2) Orient the observers.

(3) Determine firing data to th e

orienting point.(4) Fire the HB/MPI registration.

(5) Determine the mean burst location.

(6) D e t e r m i n e cha r t da t a and

registration corrections.

12-14. SELECTING ANORIENTING POINT

a. The S3 or FDO selects an orientingpoint at which all of the rounds will be fired.This point may be located at a grid

intersection for convenience. The orientingpoint is only a temporary point on the firingchart. After the firing data have beendetermined, the orienting point is no longerneeded.

b. For an HB and an MPI registration,the orienting point should-

(1) Be visible to both observers.

(2) Be close to the center of the area ofresponsibility unless eight-direction met is tobe used to determine a valid GFT setting.

(3) Ensure the apex angle is greaterthan 150 mils (preferably 300 mils). The apexangle is the angle formed by the lines fromeach observer to the orienting point (fig 12-7).

(4) For an MPI registration, th eorienting point should be in a relatively flat(level) area that is free of obstructions.

(5) For an HB regis trat ion, th e

orienting point must be high enough toensure an airburst. Fifty meters above theground is usually sufficient, but the selectedheight of burst must be at least 2 PEHB-above

the ground. For example, the FDO for anM109A3 unit has selected an orienting pointfor an HB registration. The range to theorienting point is 4,550 meters. The unit will

Figure 12-7. Apex angle.

be firing charge 4GB. Enter table G of theTFT for charge 4 with the range expressed tothe nearest 500 meters. Extract an 8-meterPEHB from column 5. Two probable errors

would be 16 (2 x 8 = 16), rounded up to thenearest 10 meters (16 * 20); thus, the lowestheight of burst that should be selected is 20meters.

c. The HB or MPI registration starts withthe fire order: HIGH BURST REGISTRA-TION AT GRID 6137, HEIGHT OF

BURST 50, NUMBER 4, LOT XY,C H A R G E 4, FUZE TIME, AT MYCOMMAND. HIGH BURST REGIS-TRATION AT GRID 6137 notifies theFDC of the type of mission to be fired (an HBregistration) and the location of the orientingpoint (grid 6137). HEIGHT OF BURST 50METERS tells the VCO the desired height ofburst above ground level (at grid 6137) for

determining site. NUMBER 4 designates thepiece that will register. LOT XY designatesthe registration lot. CHARGE 4 designatesthe charge to be used. FUZE TIME indicatesthe fuze type. AT MY COMMAND meansthat the FDO wants to control the exact timeeach r o u n d wil l be f i red. AT MYCOMMAND is used to ensure that eachobserver sees the burst from each round. Anyelements of the fire order already addressedin unit SOP need not be announced to the firedirection center.

12-11



FM 6-40

12-15. ORIENTING THEOBSERVERS

a. After the orienting point has beenselected and the fire order has been issued,the two observers must be told whereto lookto observe the rounds. The observer's

locations are plotted on the firing chart, andthe direction and distance from each observerto the orienting point are measured. The VCOuses the distances and the VI between eachobservation post and the orienting point todetermine the vertical angle for eachobserver. The vertical angle is determined byuse of the C- and D-scales of the graphicalsite table..

b. A message to observer is sent to bothobservers. The message to observercontainsthe information needed to tell the observers

where to orient their instruments to see thebursts. It is recorded on DA Form 4201(High-Burst [Mean Point of Impact]Registration). The message contains thefollowing parts:

(1) A warning order (OBSERVEHIGH-BURST REGISTRATION). Thewarning order instructs the observers toprepare to observe a registration and tellsthem for what type of registration' they arepreparing.

(2) Orienting data for observer 01(01 DIRECTION 0383, VERTICALANGLE PLUS 17). The HCO has measuredthe chart data from 01 to the orienting point.The direction reported to the observer is thedirection determined on the firing chart. TheVCO determines the altitude of the gridintersection (grid 6137) and then adds theHOB to determine the altitude of theorienting point.

EXAMPLE:Orienting point altitude = ground altitude +HOB

Ground altitude+ HOBOrienting point altitude

375+ 50425

The VCO subtracts the altitude of theobserver (370) from the altitude of the

orienting point to determine the VI (425 - 370- +55). The VCO determines 01's verticalangle (+17) by use of the C- and D-scales ofthe GST, the VI (+55), and the distancemeasured by the HCO (3,380 meters).Knowing the vertical angle and directionreported to observer 01 will enable 01 toorient on the orienting point.

EXAMPLE:

VI 'distance = VA(+55) D-scale+4 (3.38) = +16.56(M-gage point,D-scale) +17

(3) A directive to O1 to measure thevertical angle. 01 is normally the controlobservation post. It has been more accuratelylocated and has the most experiencedobserver. Observer 01 measures the verticalangles that will be used to compute thealtitude of the mean burst location. Only oneobserver's vertical angle is required.

(4) Orienting data for observer 02 .The HCO measures the chart data from 02 tothe orienting point. The VCO subtracts thealtitude of the observer (391)-from the altitudeof the orienting point (425) to determine

theVI (425 - 391 = +34). The VCO determines 02'svertical angle (+11) by use of the C- andD-scales of the GST, the VI (+34), and thedistance measured by the HCO (3,060meters). Knowing the vertical angle anddirection reported to observer 02 will enable02 to orient on the orienting point.

(5) A directive to the observers toreport when they are ready to observe.When the observers report they are ready toobserve, the FDC can begin the registration.

c. Each observer orients his instrumenton the direction and vertical angleannounced to him and reports to the FDCwhen he is ready to observe.

d. The survey section provides theirection and distance from 01 to 02. Thefollowing are provided:Direction 01 to 02 1,464 milsDistance 01 to 02 2,475.1 metersThe computer records this information on DAForm 4201 (fig 12-8) and determines thedirection from 02 to 01 by adding (or

12-12



FM 6-40

subtracting) 3200 to (from) the direction from01 to 02.

12-16. DETERMININGFIRING DATA

a. The HCO determines the range anddeflection from the battery to the orienting

point and announces the data to thecomputer. The computer records the data onthe record of fire (fig 12-9).

b. The VCO subtracts the altitude of thebattery (355) from the altitude of the orienting

point (425) to determine the VI (425 - 355 =+70). The VCO determines the site to be +17 by

HIGH BURST (MEAN POINT OF IMPACT) REGISTRATION

For use of this form, see FM 6-40; the roponent agency is US Army Training and Doctrine Command.

COMPUTATION OF HB (MPI) LOCATION

Message to Observers

0S IZ cs63%A 4- tDis A z O - 0 2 4.. I bz)I. e.. i , / A 4 ot -o,-02

ME AS URE - ,E V 4,_+3200

Figure 12-8. Message to observer.

RECORD OF FIRE

CALLOR IRE ___ AcT 3 6 FS

Observer AF/FFE/IS/S Tgtn' . 0 100/P Z

Grid: R 7. 13

Polar-Dir Di/0 _VA 7/,V20/R

Shift : Dir L/P ./- U/DSi+1-0 TomSi NOBCorr

FIRE RDER OfCorr Si 7 / 7INITIALFIRECOMMANDS r%'MIt A T gChtOf3.222. d 2 Z

Tgt Location ro i t FrngSUBSEQUENT FIRE COMMANDS

... . . . . . .. ... ..

Dir, MF Dew Pg NOR MF, Sb, FS" C h r T i C o r Dhat NR S El GE lap Type___, F___Ti Crr Chg, F: Cor T f ( ) Fired Pg Carr

--'ocaion00, Urn it .Ui illT FIRO MMANGrD ST Ielo

Figure 12-9. High-burst record of fire.

12-13



FM 6-40

using the D-scale and the site-range scale(charge 4, TAG) of the GST. The VCOannounces the site to the computer.

c. The computer records the site on therecord of fire and determines and announcesthe fire commands to the battery. No GFTsetting is available.

12-17. FIRING THE HB/MPIREGISTRATION

a. After both observers have reportedthey are ready to observe and the base pieceannounces it is ready to fire, the FDO beginsfiring the registration. The first round that isfired may not be observed by either of theobservers.

Nonstandard conditions maycause the round to burst outside the field ofvision of the observer's instrument. After thefirst round, both observers should adjusttheir instruments so that the actual burstlocation of the round is in the center of thefield of vision of their instruments. Theremay be times when the nonstandardconditions cause the round to land behind ahill or in a ravine (out of sight of one or bothobservers). If this happens, the firing data tothe orienting point are changed until both ofthe observers can see the bursting rounds.Remember, if the orienting point is changedto a location that is not near the originalorienting point, new orienting data must besent to the observers (a new message toobserver) so they can orient on the newlocation. Sometimes, graze bursts will occurat the start of a high-burst registration. Theobserver's data for these rounds cannot beused to determine the mean burst location. Inthis case, the HOB is raised by at least 2probable errors in HOB (table G of the TFT).The firing data are recomputed.

b. Once the observers have oriented onthe actual location of the bursting rounds, thefiring data are not changed. All rounds usedto locate the MBL must be fired with the sameset of firing data. Once the observers havelocated the actual burst and are oriented, themethod of fire may be changed to NUMBER4,6 ROUNDS (or however many rounds arerequired) AT (so many) SECONDS. Thetime interval between rounds must be longenough for the observers to identify eachround and record the data to that round.

c. When both observers have reportedthat they have observed the bursting round,the computer transfers the firing data to DAForm 4201 and writes See attached record ofhigh burst (MPI)" on the record of fire. Allremaining information from the registrationis recorded on the DA Form 4201.

d. After each round fired has beenobserved, the observers report the direction toeach round from their location, and observer01 reports the vertical angle from hislocation. The computer records the data onDA Form 4201 as they are sent by theobservers. The FDO must determine if anyrounds fired were erratic and should bedisregarded. There are no exact rules fordetermining which rounds are erratic. Thefollowing are three ways in which erraticrounds may be determined. They are meantas guidelines only.

(1) Determine the mean burst locationby use of graphic intersection (para 12-18).Using the range to the mean burst locationexpressed to the nearest 500 meters,determine the PER and PED and construct abox (8 PER x 8 PED) centered over the MBLand along the gun-target line. Reject anyrounds that plot outside this box (fig 12-10).

ERRATIC

ERRATICFigure 12-10. PER box for

registration.

MEAN BURST

LOCATION

a high-burst

(2) At the range to the mean burstlocation expressed to the nearest 500 meters,determine the PEHB. Using the 01's reportedvertical angles, the measured distance from01 to the MBL, and the ground altitude,determine the altitude of the mean burst

12-14



FM 6-40

location: Determine the altitude of eachround, and compare this altitude with theaverage altitude. Reject any round that fallsoutside the average altitude ±4 PEHB.

(3) The FDO may use his judgment and

experience in determining if a round shouldbe rejected. Care must be taken to ensure thaterratic rounds are not used or that usablerounds are not rejected. If a rouxd isconsidered erratic because of the reporteddirection or vertical angle from one observer,the data from the other observer must also bedisregarded.

12-18. DETERMINING THEMEAN BURST

LOCATIONa. The observer's measured azimuths are

listed, in order for each round, on DA Form4201 as they are sent to the FDC by theobservers (fig 12-11). As the round is fired, theround number is circled to record theexpenditure of rounds during th eregistration. Some rounds may be considered

Figure 12-11. ' Observer's measured azimuth.

erratic. Erratic rounds are crossed out, androunds may be fired to replace them.

b. After the data from the six usablerounds have been recorded, the FDCdetermines the mean burst location. The

location isdetermined by one of three

methods. The methods are listed inincreasing order of accuracy and time ofcomputation'. The method used by the FDCwill be determined by the tactical situation.In most cases, the graphic intersectionmethod is acceptable. However, when it isnecessary to increase accuracy (nuclear firemission), the other methods should be used iftime permits.

(1) Graphic intersection. Theobserver's average directions are drawn on

the firing chart. The point atwhich the

directions intersect is the mean burstlocation.

(2) Polar plot. The direction anddistance from 01 to the MBL are determined,and the MBL is polar plotted on the firingchart.

(3) Grid coordinates. The actual gridcoordinates of the mean burst location arecomputed and then plotted on the firingchart.

c. Procedures for use of the graphicintersection method are as follows:

(1) The usable observer readings aretotaled on the form, and the average readingis obtained by dividing the total by thenumber of usable rounds (in this case six).The averages are determined to the nearestmil.

(2) Using the RDP, the HCO sets off theaverage direction from 02 to the HB and

draws a construction line along the left edgeof the RDP with a 6H pencil. He then sets offthe average direction from 01 to the HB. Thepoint at which the two lines intersect is themean burst location. A pin is placed at theMBL, and the distance from 01 to the HB is

measured.

(3) The computer uses the distance from01 to the MBL and 01's vertical angle todetermine the altitude of the mean burstlocation.-

12-15



FM 6-40

(a) The HCO uses the RDP andmeasures the distance from 01 to the meanburst location. He announces the result to theVCO (01 DISTANCE 3450).

(b) The VCO uses 01's average

vertical angle (+20), the distance (3450), andthe GST to determine the VI between 01 andthe MBL ([+20 x 3450], C- and D-scales ofGST = VI [+68 meters]). The VCO announcesVI +68 METERS.

(c) The computer adds the VI to thealtitude of 01 (370 + [+68] = 438). The altitudeof the MBL is 438.

d. Procedures for use of the polar plotmethod are as follows:

(1) Determine the average observerreadings as explained in paragraph c above.

(2) Using the next section of the form,determine the interior angles of a triangleformed by the two observers and the meanburst location (fig 12-12 and 12-13). If 01 ison the left of 02, cross out the section marked

01 on the right. If 01 is on the right of 02,cross out the section marked 01 on left.

Figure 12-12. Determining interior angles.

(3) Completing the appropriate side ofthe form, determine the angle at 02 (4. at 02)(fig 12-13).

Figure 12-13. Polar plot method.

12-16



(4) After the angle at 02 has beendetermined, compute the distance from 01 tothe mean burst location by using logarithmsfound in TM 6-230. Use the section of theform labeled Distance 01 HB (MPI) to

determine the distance 01to the mean burst

location (fig 12-14). You may also use a sliderule or a calculator to compute the distancefrom 01 to the mean burst location. Use theformula in figure 12-15.

Distance 01 NB (MPI'

Log base 01 - ' 02

+ Log sinz4at 02 & S

Sum C,) 3 5{20.46-- ogsin.Apex AngleSgg3, o 7. ,zLot 01 H M I)2 5

Dist 01 -- HB (MPI)I

Figure 12-14. Determining the distance from 01to the mean burst location.

IIII I

MEAN BURSTLOCATION

DISTANCE 01 TO MEANBURST LOCATION

= DDISTANCE 01 TO 02 = KAPEX ANGLE - A

• ANGLE AT 02-02

D (K) (SIN 4 02)SIN 4 A

Figure 12-15. Computing the distancefrom 01 to the mean burstlocation.

(5) The distance from 01 to the meanburst location is expressed to the nearest 10meters (3,437 meters z 3,440 meters).

(6) The HCO places the vertex of theRDP on 01 and moves the RDP to the averagedirection determined for 01 to the mean burstlocation (0356 mils). The HCO places a pin at

FM 6-40

12-17



FM 6-40

the distance determined for 01 to the meanburst location (3,440 meters). This is the meanburst location.

(7) The VCO uses the average verticalangle determined for 01 (+20), the distance

from 01 to the mean burst location (3,440meters), and the GST to determine the VIbetween 01 and the MBL (20 x 3,440 meters,C- and D-scales of GST= VI +68). Add the VI(+68) to the altitude of 01 (370) to determinethe altitude of the MBL (370 = (+68) = 438).

e. Procedures for use of the gridcoordinate method are as follows:

(1) Compute the average directions,interior angles, and distance from 01 to themean burst location as in paragraphs c and dabove.

(2) Determine the bearing angle from01 to the mean burst location. Using thediagram (with the top of the formrepresenting north or 0 mils), draw a lineapproximately along the average azimuthfrom 01 to the mean burst location. Draw thisline in one of the four quadrants of thediagram. In each quadrant are theinstructions for determining the bearingangle in that quadrant (fig 12-16).

Figure 12-i6. Computation of mean burst location.

12-18





FM 6-40

(2) If the firing weapon is not overbattery center, the deflection used to fire thesix usable rounds is the correct deflection.The adjusted deflection is determined in thesame manner as the adjusted deflection for aprecision registration when the piece is not

over battery center (fig 12-19).c. Adjusted Time.

(1) If the VI between the battery and theMBL is less than or equal to 100 meters, the

fuze setting used to fire the six usable roundsis the adjusted time.

(2) If the VI is greater than 100 meters,the adjusted time must be modified to correctfor an inaccuracy introduced by the largecomplementary angle of site (fig 12-20). The100-meter VI is only a rule of thumb. TheCAS may affect adjusted time at VIs lessthan 100 meters. The FDO should check theeffects of CAS any time he feels it will affectadjusted time.

FORM 4757 SEPS84EOITION OF OCTOBER 1978 S OBSOLETE

Figure 12-19. Registration/special correction work sheet for the high-burst registration.

Figure 12-20. Adjusted time with a vertical interval greater than 100.

12-20



FM 6-40

(a) Fuze setting is determined as afunction of the elevation and CAS. When the

VI is less than or equal to 100 meters, the CASis so small that it has little effect on thequadrant and fuze setting fired and is

disregarded.The CAS is small when

compared to the elevation and will not affectthe fuze setting.

(b) If the VI is greater than 100

meters, the value of the CAS becomesincreasingly large and begins to affect thefuze setting. In this case, the CAS must beadded to the elevation to determine the properfuze setting.

(c) As the CAS increases, the fuzesetting must be increased to reach the desiredbursting location. If the effect of CAS is not

included in the fuze setting, the projectile willburst before reaching the desired location.

(d) The adjusted time when the VI is

greater than 100 meters is determined asfollows:

* Determine site and angle of site to themean burst location by use of thegraphical site table.

* Determine the CAS by subtracting theangle of site from site (s i -4si = CAS).

* Add the CAS to the adjusted elevation,and determine the fuze settingcorresponding to this value (FS el +CAS).

* Subtract the fuze setting corre-sponding to elevation + CAS from thefuze fired to determine the total fuzecorrection ([FS fired] - [FS ,: el + CAS]

= tot fz corr).

* Add the total fuze correction to the fuzesetting corresponding to the adjusted

elevation. The result is the adjusted

time ([FS adj iel]) + [tot fz corr]= ad j-. i).

EXAMPLE:

Given: Registration charge: charge 4Adjusted elevation: 302Vertical interval: +150Chart range: 5,000 metersFuze setting firedduring registration: 18.1

* Determine site and the angle of site (VI

= 150, charge 4 at 5,000 meters, GSTsite-range scale = 134). (Angle of site VI

= 150, C- and D-scales of GST at range5000 = +31.)

* Determine CAS. Site - angle of siteCAS. (+34 - [x31'] = +3).

* Determine the elevation + CAS.

Adjusted elevation + CAS = el + CAS(302 + '3] = 305).

* Determine the fuze setting corre-sponding to elevation plus CAS. Placethe MHL of GFT on 305, and read thefuze setting of 18.4 under the MHL.

* Determine the total fuze correction.Fuze setting fired in registration fuze

setting corresponding o the elevation +CAS = total fuze correction (18.1 - 18.4 =

-0.3).* Determine adjusted time. Fuze setting

corresponding to adjusted elevation +

total uze correction = adj time (18.2-0.3= 17.9).

(adj el)

302 +3 (CAS) 18.1 (time fired)

305 (el + CAS) -0.3 total fz corr

18.4

18.2-0.3 (TFG)17.9 (adi ti)

Section IVRADAR REGISTRATIONS

12-21. EMPLOYMENT

Field artillery radars can conductregistrations. The conduct of a radar

registration is similar to that of other

HB/MPI registrations. The unique

procedures and requirements for the

12-21



FM 6-40

AN/MPQ-4 and the AN/TPQ-36/37 radarsystems are discussed in this section.

12-22. ADVANTAGESThe advantages of a radar registration

areas follows:

a. It requires only one observation post-the radar.

b. It requires less survey, fewercommunications facilities, and lesscoordination.

c. It can be conducted quickly.

d. It can be conducted during periods ofpoor visibility. The AN/MPQ-4 radar mayconduct only MPI registrations duringperiods of poor visibility.

e. It gives the grid and altitude of theMBL or the grid and altitude of each round.

12-23. CONDUCTING ARADARREGISTRATION

a. The six steps in conducting a radarregistration are-

(1) Selecting an orienting point.(2) Orienting the radar.(3) Determining firing data to the

orienting point.(4) Firing the HB/MPI registration.(5) Determining the mean burst

location.(6) Determining chart data and

registration corrections.

b. Radar registrations with theAN/TPQ-36/37 radar require only anelectrical line of sight from the radar to theorienting point. High-burst registrationsconducted with the AN/MPQ-4 radar requirean optical line of sight and an electrical lineof sight. The MPI registrations with theAN/MPQ-4 radar require only an electricalline of sight.

c. The AN/TPQ-36/37 radar operatorreports the grid and altitude of each burstlocation. The AN/MPQ-4 radar operatorreports the grid and altitude of the MBL afterthe last round has been located.

12-24. SELECTING ANORIENTING POINT

Coordination and mutual understandingmust exist between the FDC and radarpersonnel in the choice of an orienting point.

a. High Burst.

(1) A N / M P Q - 4 radar. For ahigh-burst registration conducted with theAN/MPQ-4 radar, the selected orientingpoint must be optically visible from the radar.For the radar operator to optically observeelevation deviations above and below theselected point, the pointing elevation of theradar must be at least 10 mils above theelevation to the radar screening crest. Theradar operator measures the elevation fromthe radar along the azimuth to the selectedburst point by sighting through the opticaltelescope.

(2) AN/TPQ-36/37 r ada r. Ahigh-burst registration conducted with theAN/TPQ-36/37 requires only an electricalline of sight to the selected point. Theon-board computer controls the radar toenable it to intersect the trajectory above thescreening crest. The radar will track theround until the airburst is detected.

b. Mean Point of Impact.(1) A characteristic of the radar MPI

registration is that the rounds usually cannotbe observed at impact, because the radar isusually positioned behind a mask.

(2) The AN/MPQ-4 radar must observethe round at some point in space where theround passes through the radar beam. Thispoint in space is called the selected datumplane-the theoretical horizontal plane of theradar beam from which radar personnel inthe AN/MPQ-4 radar system can computethe location of the usable rounds (fig 12-21).

(3) The AN/TPQ-36/37 radar systemsset up a "window" through which theprojectile will pass (fig 12-22). The window isreferred to as the friendly fire search fence.The search fence allows for the bestprobability of detection. After the orientingpoint has been selected, the FDO issues hisfire order.

12-22







FM 6-40

Figure 12-23. Example of an AN/MPQ-4 radar-observed MPI registration.

12-25

Figure 12-24. Example of an AN/TPQ-36/37 radar-observed high-burst registration.



Fii 6-40

Note. The AN/TPQ-37 radar section willrequest SHOT, will request SPLASH, andmay make mission at their command.

12-27. FIERENG THE HIJB/MIPEREGJ[STRATON

a. AN/MPQ-4 Radar.

(1) The report for the AN/MPQ-4 radarincludes the altitude of the orienting point. Toreduce transmission time, the radar operatorwill queue the radar for each round fired.Therefore, the mission will be fired AMC, andSPLASH

will be sent. ALTITUDE 450, ATMY COMMAND, REQUEST SPLASH,READY TO OBSERVE, OVER.

(2) When the radar reports READYTO OBSERVE and the firing piece reportsREADY, firing begins. If the first round isnot visible in the telescope reticle and on theB-scope of the radar, the antenna isreoriented to the center of the burst, and theround is not used. If the first round burst morethan 5 mils below the center of the reticle, thealtitude must be increased and the roundmust not be used. After each

round is fired,the radar operator reports OBSERVED orU N O B S E RV E D . If the report OB -SERVED is followed by REQUEST SITEINCREASE, the burst is occurring too low.The quadrant elevation must be increased bythe number of mils necessary to raise theburst approximately 2 PEHB. All of theprevious rounds are discarded.

(3) After the rounds have been fired, theFDO has a number of options for determiningthe number of usable rounds he will need to

determine the registration corrections.

(a) The FDO may allow the radarperator to determine which rounds areusable. The operator reports to the FDC thenumber of usable rounds and the grid andaltitude of the mean burst location.

(6) The FDO may issue separateguidance on how the usable rounds will bedetermined.

(c) The FDO may request the grid andaltitude of each round fired and determine'theusable rounds himself.

b. AN TPQ-36/37 Radar.

(1) The radar on-board computer usesthe orienting data to check the trajectory andto determine whether it fits the radar'scapabilities. Before firing, the radar operatordetermines whether the data are acceptable,marginal, or unacceptable. The radar sectionreports when they are ready to observe. ATMY COMMAND (REQUEST SPLASH),READY TO OBSERVE, OVER. Since theradar operator checks the acceptability of theorienting data before firing begins, all roundsfired should be acquired by radar. If the firstround is not visible, an error has occurred.The radar operator informs the FDC that theround was unobserved. The FDC shouldverify firing data. If no errors are found andthe next round is unobserved, the FDC shouldcompute new orienting data and send it to theradar operator.

(2) If the grid and altitude of each roundare reported, the FDO will determine theusable rounds.

12-28. DETERIENINGTHEMEAN BLRST

LOCATION

a. AN/MPQ-4 Radar.

(1) On completion of an HB registra-tion, the radar operator will normallycompute and report the grid and altitude ofthe MBL for the usable rounds. In an MPIregistration, the radar operator computesand reports the grid of the MBL and thealtitude of the selected datum plane.

(2) If the grid and altitude of each burstare reported, the FDO will determine theMBL by averaging the reported grids andaltitudes of the usable rounds.

b. A N TPQ-36/37 Radar. The radaroperator reports the grid location and altitudeof each burst. The FDO averages the gridsand altitudes of the usable rounds to computethe mean burst location.

12-26



FM 6-40

12-29. DETERMINING CHARTDATA AND REGISTRA-TION CORRECTIONS

After the MBL and altitude have been

determined, theprocedures for computing

chart data and registration corrections arethe same as those for regular HB/MPIregistrations.

Section VREGISTRATION CORRECTIONS

12-30. DESCRIPTIONa. Registration corrections consist of

total range, fuze, and deflection corrections.

The FDC computes these corrections bycomparing the initial chart data to the

adjusted data resulting from a registration.In situations in which a registration is not

feasible, the corrections may be mathe-matically obtained through solution of a met

(chap 10) and used as the basis for a GFTsetting.

b. When properly applied, registrationcorrections make it possible to fire for effecton accurately located targets within transferlimits without an adjustment phase.

Registration corrections also facilitate replotof targets located by adjustment of fire (chap8).

c. The corrections determined by the

registration are applied to the GFT.

Registration corrections can be computed byand stored in the ballistic computers (BCS,TACFIRE, and FADAC). The computersautomatically apply these corrections tofiring data.

not used to derive OFT settings. It can

store/apply only one set of residuals percharge.

12-31. COMPUTATION OFTOTAL RANGECORRECTION

a. When standard conditions exist, theelevation fired to achieve the chart range is

the elevation listed in the firing tables forthat chart range. When nonstandardconditions exist, an adjusted elevation must

be fired to achieve the same chart range.

b. The total range correction is the

difference, in meters, between the initialchart range from battery center and the firing

table range corresponding to the adjustedelevation. Determine the total rangecorrection as follows:

(1) From the TFT or the GFT, determine

the range to the nearest 10 meterscorresponding to the adjusted elevation.

(2) Subtract the initial chart (or

achieved) range from the range corre-sponding to the adjusted elevation. The result

is the total range correction. The total rangecorrection is always a signed value.

EXAMPLE

An M109A3 howitzer battery ha s

registered using charge 4GB. The GFT

setting has been corrected to compensate for

adjusting piece displacement. The initial

chart range was 4,620 meters, and the

adjusted elevation was 267.* By use of the GFT, the range

corresponding o the adjusted elevationof 267 is determined to be 4,500 meters.

* The initial chart range is subtractedfrom range corresponding to the

adjusted elevation. The result is a total

range correction of -120 meters (4,620 -4,500 = -120 meters).

* The above procedures can be portrayedby use of a portion of the lazy Z.

12-27



FM 6-40

TOTAL RANGE CORRECTION 4500

-120

4620 267

The difference between the initial chartrange and the range corresponding to theadjusted elevation is -120. The total rangecorrection is used in solving the concurrentmet message.

12-32. COMPUTATION OFTOTAL FUZECORRECTION

a. The time portion of a registrationresults in an adjusted time (fuze setting). Thetime corresponding to the adjusted elevationis the time that must be compared to the

actual adjusted time determined by firing.The difference between the time corre-sponding to the adjusted elevation and theadjusted time is the total fuze correction.

b. The total fuze correction is determinedby subtracting the time corresponding to theadjusted elevation (or elevation plus CAS ifthe VI is greater than 100) from the adjustedtime.

267 16.2

16.0 TOTAL FUZE CORRECTION

12-33. COMPUTATION OFTOTAL DEFLECTIONCORRECTION

a. The total deflection correction is thecorrection that must be added to the chartdeflection to correct for the effects ofnonstandard conditions. The total deflectioncorrection is determined on DA Form 4757.

b. The total deflection correction isdetermined by subtracting the chart

deflection from the adjusted deflection.c. A GFT deflection correction is

determined by subtracting the driftcorresponding to the adjusted elevation fromthe total deflection correction. The GFTdeflection correction remains the same for allelevations fired with the registered charge.The total deflection correction may changebecause of changes in drift depending on theelevation being fired.

EXAMPLE:

Continuing the example above, the batteryobtained an adjusted time of 16.2. The time EXAMPLE:corresponding to the adjusted elevation is The battery's chart deflection is 3237, and16.0. The time corresponding o the adjusted adjusted deflection is 3255. The totalelevation is subtracted from the adjusted deflection correction is L18. The drifttime to determine a total fuze correction (16.2 corresponding o the adjusted elevation (267)- 16.0 = +0.2). This procedure is portrayed by (from the GFT) is L5. The GFT deflectionusing the other half of the lazy Z. correction is L13 (fig 12-25).

Figure 12-25. Deflection correction.

12-28



FM 6-40

12-34. REGISTRATIONTRANSFER LIMITS

The corrections determined from aregistration are valid only within certain

range and deflection limits. Theregistration

corrections for nonstandard conditions are

valid only when firing toward theregistration point. For example, when firing

on a different azimuth, the wind will not

affect the round in the same manner as it didalong the azimuth to the registration point.

Registration corrections are valid only for the

position from which the registration was

fired (except for offset registrations).

a. Range Transfer Limits.

(1) One-plot GFT setting.The range

limits for a one-plot GFT setting are shown

on the graphical firing table. As long as thechart range of the registration point isbetween the leftmost and the rightmost met

check gage points, the target is within therange transfer limits. The charge 4 GFTrange limits are from range corresponding toelevation 150 (the first red-numberedelevation) to elevation 630 (the last red

number on the elevation scale).

(2) Two-plot GFT setting. The range

limits for a two-plot GFT setting are betweenthe two ranges used to apply the GFTsettings. This type of GFT setting begins to beinvalid outside these two ranges.

(3) Multiplot GFT setting. The rangelimits for a multiplot GFT setting areeliminated when three or more sets ofcorrections are available for the same charge.When using the multiplot GFT setting, thereare no range transfer limits.

b. Deflection Transfer Limits.

(1) The registration corrections arevalid only within certain deflection transferlimits.

(2) When the chart range to a target is

10,000 meters or less, the deflectioncorrections are valid within an area 400 mils

left and 400 mils right of a line between the

battery and the registration point (mean

burst location) (fig 12-26).

Figure 12-26. Registration transfer limits-10,000 meters or less.

(3) When the chart range to a target is

greater than 10,000 meters, the registrationcorrections are valid within an area 4,000meters left and 4,000 meters right of a line

drawn between the battery and theregistration point (mean burst location) (fig12-27).

(4) Registration corrections may be

determined throughout the entire 6,400 milsaround the battery by using the eight-direction met technique.

Figure 12-27. Registration transfer limits-greater than 10,000 meters.

12-29

AZIMUTH TO REGISTRATION POINT

(nU

wi-

0000



FM 6-40

T o enhance survivability on th ebattlefield, a unit must take max-

imum advantage of the natural coverand concealment offered by the terrain

and vegetation.When a unit is so

positioned, corrections are required toobtain an acceptable burst pattern(sheaf) in the target area. These

corrections, known as hasty correctionsand special corrections, compensate for

the differences in muzzle velocities

between platoons and for the position-ing of the weapons.

Survivability considerations requirethe occupation of positions in excess of

400 by 200 meters. Terrain gun positioncorrect ions do not allow for th eoccupation of battery positions in excessof 400 by 200 meters without sacrificingeffectiveness in the target area .Therefore , t e r ra in gun posi t ioncorrections have extremely limited use

on the battlefield. Applying specialcorrections to a mission satisfies therequirement to place effective fires on

the target without limiting the size ofthe battery position.

There are certain types of missions theFDC must be prepared to conduct thatrequire specia l a t ten t ion . These

situations require special processingand are discussed in this chapter. Thesetypes of missions include the following:

" Attacking large targets.

* Delivering final protective fires.

" Answering fire requests from anair observer.

• Talking an untrained observerthrough a fire mission.

* Firing across grid zones.

* Using high-angle fire.

Section I.BASIC CORRECTION DATA

13-1. PIECE DISPLACEMENT

a. Manual procedures for determiningspecial corrections require that the relativeposition of pieces in the battery area beknown (piece displacement). The FDC locateseach weapon in the firing unit by use of theinformation provided by the advance party.Piece displacement is the number of metersthat the piece is displaced forward or back

and right or left of the geographical batterycenter grid. It is measured on a line parallel to( forward/back) and perpendicular to(right/left) the azimuth of lay.

b. Piece displacement can be determinedby estimation/pacing, hasty traverse, or

survey. Usually, estimation and pacing arenot accurate enough for the large distancesencountered at battery positions. The hasty

13-1



FM 6-40

traverse technique is a quick, accurate meansof determining piece displacement by use ofthe M10/M17 plotting board. The surveytechnique provides grid coordinates for eachweapon location.

13-2. ESTIMATION/PACINGa. Estimation is the least desirable

method. Using this method, the batterycommander or executive officer estimates thedisplacement of the pieces from the GBC,parallel and perpendicular to the azimuth oflay.

b. The pacing method provides fairaccuracy in small open areas, but it is timeconsuming. Using this method,the batterycommander or executive officer determines

piece displacement by pacing from the GBC,parallel and perpendicular to the azimuth oflay.

13-3. HASTY TRAVERSEThe hasty traverse method is a rapid andaccurate way to determine piece displace-

ment. It is a graphic solution for piecedisplacement that uses the M1O/M17 plottingboard. The advance party provides the FDCwith initial lay deflection and distance to thegeographical battery center (GBC) and toeach gun position.

13-4. SURVEYSurvey (grid andaltitude) to each gun

position, provided by field artillery surveycrews, is the most accurate method. Piecedisplacement is computed by determining thedifference between the grid coordinates fromthe GBC to each weapon position.

13-5. BALLISTICCOMPUTERS

The BCS does not consider piecedisplacement in firing data computation. Itlocates each weapon by grid coordinates anduses this information when it computesindividual

trajectories. The FADAC accountsfor individual grid locations for each firingunit.

13-6. DESCRIPTION OF THEM10/M17 PLOTTINGBOARD

The M10/M17 plotting board is used tocompute special corrections. The plottingboard consistsof three basic parts.

a. Gridded Base. The gridded base (fig13-1) normally represents the target area.The small red squares may be assigned anyvalue depending on the intended use.

VERNIER SCALERED INDEX ARROW

8 0 , % o.... MILLIMETERSCALE

- CENTER HORIZONTAL LINE

-INCH SCALE

LT R t VERTICAL LINE & M 10 YARD SCALEM 17 METER SCALE

Figure 13-1. Gridded base.

13-2



FM 6-40

Normally the following values, in meters, areused:

Special correctionsEmergency FDC

Laser hasty adjustment

20200

The red arrow on the base represents thedirection of fire. The center vertical line is areference line used to measure lateralcorrections. The center horizontal line is areference line used to measure rangecorrections. Although it is not normally used,

the vernier scale allows the visualinterpolation of azimuth or deflection to the

nearest mil. Other scales on the base are amillimeter scale (top) and an inch scale (rightside). On the bottom of the base there are

scales for measuring distances on maps. The

scale on the M17 is in meters,and the scale on

the M10 s in yards. The screw or rivet is used

to hold the clear plastic disk to the base and

may be used to represent one of the following:

(1) Geographical battery center.

(2) Target.(3) Observer location.

(4) Location of the last burst.

b. Clear Plastic Disk. The clearplastic disk (fig 13-2) normally represents the

battery position and has three scales aroundthe outside edge.

RED SCALE FOR OUTER BLACK SCALE FOR

CHART DEFLECTION AZIMUTH OR DEFLECTION

21

,.. B,13LACK

a :. o%

LINE

' '/"'' /,,,,21,i ,r,,, \;"' N ER BLA CK S CALE

(M12-SERIES SIGHT FOR

HASTY TRAVERSE ONLY)

,y--3

F i u e 32,Cea latc ik

(1) The outer black scale is used forazimuths or initial lay deflections. It is

graduated every 10 mils and numbered every100 mils from 0 to 6300.

(2) The red scale is a chart deflectionscale.

(3) The inner black scale is used

primarily for the M12-series sight for hastytraverse.

13-7. PREPARING THE M10/M17 PLOTTING BOARD

a. General . Prepare the M10/M17plotting board for the manual solution of

special corrections in the following manner:

(1) Disassemble the plotting board byremoving the clear plastic disk from thegridded base.

(2) To prepare the clear plastic disk forthe M100-series sight deflection, extend thered deflection scale by crossing out the red

numbers 1, 2, 3, 4, and 5 after number 32 andnumbering from 33 to 63 (fig 13-3).

(3) To prepare the M12-series sight,

extend the red deflection scale by numberingfrom 6 to 31 after the red numbers 1, 2, 3, 4,and 5.

Figure 13-3. Preparing the disk.

13-3



FM 6-40

(4) Reassemble the plotting board.(5) To describe targets on the plotting

board for the M100- or M12-series sight,construct an azimuth index.

(a) Orient the 3200 (outer black scale)over the red index arrow.

(b) Opposite the azimuth of lay (outerblack scale), mark an azimuth index on thebase. The relationship between azimuth anddeflection has now been established. To setoff an azimuth, turn the azimuth on the outerblack scale opposite the azimuth index.

(6) The plotting board is now ready foruse in special corrections.

b. Plo t t ing Has ty Traverse Data(Ml O0-Series Sight) . Apply

hastytraverse data to the M1O/M17 plotting boardin the following manner:

(1) Plott ing the aiming circlelocation. To plot the aiming circle (AC)location (fig 13-4), place the initial deflectionfrom the AC to the GBC over the red index

arrow. Use the outer black scale (0 to 6300).Measure the distance from the GBC to the ACalong the center vertical line from the centerrivet toward the red index arrow. Place a do tthere, circle it, and label it AC.

(2) Plotting the weapon location.To plot the weapon location (fig 13-5), placethe initial lay deflection from the AC to thegun position (outer black scale) over the redindex arrow. Measure the distance down fromthe AC on a line parallel to the center verticalline. Place a dot there and circle it. Label thedot to correspond to the weapon number. Usethis procedure for all other weapons.

Figure 13-5. Plotting the weapon locations-hasty traverse (M100-series sight).

(3) Plot t ing the platoon centerlocation. To plot the platoon center location,identify the dots representing the two guns ofa platoon. Using a straightedge, draw a lightline between the two dots. Place a dot at themidpoint of the line. This dot represents theplatoon center. Label the dot with theappropriate platoon designation.

*(4) D e t e r m i n i n g and record ingpiece displacement on the computer'schecklist. To determine piece displacement(fig 13-6), rotate the 3200 (inner red scale)over the red index arrow, and read piecedisplacement left/right and forward/back ofthe GBC, represented by the center rivet.Record the piece displacement on DA Form5338-R (Computer Checklist) (fig 13-7 andapp J).

13-4

S

Figure 13-4. Plotting the aiming circle location-hasty traverse (M1 00-series sight).



FM 6-40

Figure 13-6. Determining piece displacement.

PIECE DISPLACEMENT DATA

~DISPLACEMENTN M E GRD LATERAL R AN GE

•

AIIN

PRIORITY TARGET INFORMATIONFINAL PROTECTIVE FIRE/

COPPERHEADGRI AG643V3_ 14 4 '

1 25. FIRE PLAN __

TIME UNIT

ON OFTARGET FINE

/31.2 TO

KNOWNPOINTTARGET

4470524Ito y

Figure 13-7. Computer checklist-piece displacement data.

13-5

LOCATION

jq a63

Z .*t A - Z r V-21. HIGH XPLOSIVE

c;,orr 4 c4 40, XAP V Y gr/vo , ZX -f-h'

I

FIRE FOR"FIRE ORDER STANDARDS ADJUST FIRE EFFECT

1. UNIT O FIRE 8 7)eY me Yl01,

2. ADJUSTING LEMENT/METHOD FFIREOFADJUSTING LEMENT

13. BASIS FOR CORRECTION

14. DISTRIBUTIONm ;rajr

5. PROJECTILE14 Ar

I. rg&Z AA Lgir-r-r16. AMMUNITION OT/CHARGE 1 -17. FUZE J00 11t4fe

8. NUMBE OF ROUNDS

9. RANGE PREAD, LATERAL PREAD, ZONE OR SWEEP Ila10. TIME OFOPENING IRE IWA RM11. ARGETNUMBER I

w W FIRE FOfi

FIRE COMMAND STANDARDS ADJUST FIRE EFFECT

12. WARNING RDER

13. PIECE TO FOLLOW/PIECE TO FIRE/IVIETHOD OF FIRE

14. SPECIAL NSTRUCTIONS

15. PROJECTILE OAFmom,

BATTERYAMMUNITION OUNT BATTERY DATA GRID/ALIIIUL)IL: UTH CALL IGN

LLC A l o o t3,7, V 0

W3 36Lzkpt 60441 fl/ 5G3 -roo %sAsj g VA

PD L130-L,

MEMO

i

I1

M wl



FM 6-40

EXAMPLE:The following data are provided to demonstrate plotting hasty traverse on the M10/M17plotting board and to determine piece displacement for a unit with the MJOO-series sight.Battery B's advance party has completed its preparation of a new position. The advance partyprovides the following hasty traverse data to the fire direction center:

FROM AC TO :

Geographical battery centerGun 1Gun 2Gun 3Gun 4Gun 5Gun 6

Azimuth of lay 6350

DEFLECTION

2060127610921881

262827213361

The FDC plots the data on the M1O/M17 plotting board and determines the followingpiece andplatoon displacement data:

RIGHT/WEAPON LEFT

1 230R

2 1O R

3 65R4 130L

5 35L

6 270L

FOR WARD/BACK

250F220F

25F

20B

240B

295B

RIGHT/PLATOON LEFT

right

center

left

R120

L35

L150

c. Plotting Hasty Traverse Data(M12-Series Sight). Apply hasty traversedata to the M10/M17 plotting board in thefollowing manner:

(1) Plott ing the a iming circlelocation.

To plot the AC location (fig 13-8),place the initial lay deflection (outer blackscale) from the AC to the GBC over the redindex arrow. Measure the distance from theGBC to the AC along the center vertical linetoward the red index arrow. Place a dot thereand circle it. Label the dot AC.

(2) Plotting the weapon location.To plot the weapon location (fig 13-9), placethe initial lay deflection over the red indexarrow.

(a) When the weapon is to the right ofthe AC in relation to the 0 to 3200 line, use theouter black scale.

(b) When the weapon is to the left ofthe AC, use the inner black scale.

(c) When the deflection from the ACto any weapon is exactly 3200, the followingapply:

* If the weapon is behind the AC, use theouter black scale.

* If the weapon is forward of the AC, usethe inner black scale.

(d) Measure the distance down fromthe AC on a line parallel to the center vertical

13-6

DISTANCE

230

465

250

280

145

385

400

FOR WARD/BACK

F235

F5

B265



FM 6-40

7 5 5 4 3 2 1MM

I tLJL

I L

I I I L LL rT=

"rr -r- -T-

T I I I I III

-II I IT

ii hL- ..ta

1.1 -1 T I I I FT I I I I I I I I

I I LA+ j± : - _- - .. , .- -

Oir L _L777 - -- -

FRIL-IT-R -:Tit

F

Figure 13-8. Plotting the aiming circle location- hasty traverse (Ml 2-series sight).

M NA

I T I I JIL A LT iiiiir

t LJL L 1A]Ill - fillTill 111 IITT[ I ]fit

T III Fit Ir I I t- Ill t Till..

-T-1I it-- I ITT[ I

I I IIs I I

11 1 _ 1 11 If It

F [NOT IF IF 1111

I L.Ll If I

I I IA

1 1 I T I I I I Ji

[TIT 17%_1 I IIF1 I i rqLu F if

Al I4

I ItT II I

+0. 1 T L Tj T.L jI I

T T 11 6

I B

I I

to

13-7



FM 6-40

line. Place a dot there and circle it. Label thedot to correspond to the weapon number. Usethis procedure for all other weapons.

(3) Applying the deflection index.Orient the 3200 on the outer black

scale overthe red index arrow. Without moving theclear plastic disk, place a mark on the basecorresponding to the common deflection(2400 or 2800, inner red scale). Label it thedeflection index.

(4) Determining and recordingpiece displacement. With the 3200 (outerblack scale) over the red index arrow, readpiece displacement lef t / r ight an dforward/back of the GBC represented by thecenter rivet (fig 13-10).

GTA 6-5-2(7)PLOTTING BORD, M-17

7j6 5 4 3 2 1M7--

6.2

5-

5$4442--

T ,FM

' ~. ... . +

.t t

Figure 13-10. Determining and recording piece displacement- hasty traverse (Ml2-series sight).

13-8



FM 6-40

EXAMPLE:

The following situation demonstrates hasty traverse determination with the M12-series sight.

Battery C's advance party has completed its preparation of a new position. The advance party

provides the following hasty traverse data to the fire direction center.

FROM A C TO: DEFLECTION DISTANCE

Geographical battery center 2060 230

Gun 1 1276 465

Gun 2 1090 250

Gun 3 1881 280

Gun 4 2629 140

Gun 5 2725 385

Gun 6 (Gun is left of aiming circle) 0169 400

Common deflection 2400

The FDC plots the dataon the M10/M17 plotting board and makes a deflection index on the

base opposite 2400 (inner red scale) and determines the following piece and platoondisplacement data:

RIGHT/ FORWARD RIGHT/ FOR WARD

WEAPON LEFT BACK PLATOON LEFT BACK

1 230R 250F right R120 F235

2 1OR 220F

3 65R 25F' center L35 F5

4 130L 20 B

5 35L 240B left L150 B265

6 270L 295B

d. Plotting Hasty Traverse by Use ofTwo Aiming Circles. Two ACs may berequired to lay the battery when widelydispersed position areas are being occupied.One of two situations must exist before hastytraverse with two ACs can be used.

(1) The geographical battery center isvisible from both ACs. After plotting the firstAC, as outlined in paragraph b orec above, usethe same procedures to plot the second AC.

(2) The two ACs are visible to each

other, but one AC does not have line of sightwith the geographical battery center.

(a) Plot the AC that has line of sightwith the GBC as described in paragraphs band c above.

13-9



FM 6-40

(b) To plot the second AC, rotate thedeflection from AC 1 to AC 2 over the redindex arrow.

(c) Mark off the distance down fromAC 1, parallel to the center vertical line. Place

a dot there, circle it, and label it AC 2. Eachweapon will then be plotted on the plottingboard from the AC from which it was laid.

e. Plotting Estimated/Paced Data(All Sights).

(1) The advance party gives the FDCpiece location data based on estimation/pacing in relation to the azimuth of lay.

(2) The FDC applies the data to theM10/M17 plotting board by use of thefollowing steps:

(a) Place 3200 (inner red scale) overthe red index arrow. This aligns the commondeflection with the deflection index.

(b) Using the center rivet as the GBC,place off the estimated/paced displacementfor each weapon. Place a dot at thecorresponding location, and label it with theappropriate weapon number.

(c) Without moving the clear plasticdisk, make the azimuth index on the base

correspond to the azimuth of lay read on theouter black scale.

EXAMPLE:Battery B's advance party has completed itspreparation of a new position. The advanceparty provides the following estimatedpaced data to the fire direction center. Dataprovided are from the geographical batterycenter.

RIGHT/ FOR WARDWEAPON LEFT BACK

1234

56

R230RIO

R6 5L130

L35L270

F250

F220

F25

B20

B240B295

f Plo t t i ng Survey Data (All Sights) .

(1) The field artillery survey party givesthe FDC the survey, grid, and altitude of eachweapon and the altitude of the geographicalbattery center.

(2) The FDC applies the data to theM10/M17 plotting board.

EXAMPLE:

Remove the clear plastic disk, and constructthe grid reference system on the base of the LONGI114,M10/M17 plotting board so that the grid 9 6a.. 3.coordinates o the GBC will correspond o the ')3 -center rivet to the nearest 10 meters.--4 I

GUN GRIDPOSITION COORDINATES

1 61082 32918

2 60861 328823 60920 32689

4 60728 326375 60839 324176 60604 32354

ALTITUDE

353

355354349

351

350

Azimuth of lay 6350

STEP 1. Prepare he M10/M17 base by use ofa grid reference system.

3-10

S





FM 6-40

a. Fire-for-Effect Mission. Forfire-for-effect mission, special correctioniare determined and applied onmission-by-mission basis depending on thtime available, target size, target shapefriendly troop locations, and accuracy of thetarget location. Special corrections ar(categorized by the type of sheaf applied to thEfire-for-effect data.

(1) Parallel sheaf. All guns fire th(same time, deflection, and quadrant. Thi,type of sheaf is the least effective, but it is themost responsive.

P

(2) Converged sheaf. Each gun fires aunique time, deflection, and quadrant thaicause all fire-for-effect rounds to impact althe same point. This special correction is usecwith poiht targets.

(3) Special sheaf. Each gun fires alseparate aiming points on the target formaximufi munition effects. The special sheafis the preferred sheaf for attacking circulartargets that have a radius greater than 100meters or that have specific shapes orattitudes.

b. - Adjus t Fire Mission. For an adjustfire mission, hasty corrections are applied toplatoon firing 'data by use of the hastycorrection tables (app A).

Note. If 'a firing unit is unable toeffectively attack a target because of targetposture, target size, munition effects, etc.,other methods of attack should beconsidered. Other methods are discussed insection III.

13-9. REGISTRATION/SPECIAL

.. CORRECTIONWORK SHEET

;DA. Form 4757 is provided for determiningand recording computations and data forregistrations, GFT settings, and specialcorrections.

ISIB

a

ILI

(2) Enter in j the registering piecet displacement (to the nearest 10 meters) and

the appropriate sign (forward [-] or back [+]).

(3) Algebraically add rn and E-J tor determine the registration achieved ran e(tothe nearest 10 meters), and enter it in.

b. Registering Piece DisplacementCorrection. Use'the registering piecedisplacement correction portion of the formin the following manner

(1) Enter in

fjf the registering piecelateral piece displacement (to the nearest 5meters) and the appropriate letter (L for left,R for right).

o(2 Wnter in J the value determinedfrom '3 (to the nearest 10 meters).

(3) Divide Eliby F5' to determinethe registering piece-displacement correction(left ar right) (to the nearest mil), and enter it

-in L..§J

c. Deflect ion Correct ion. Use the

deflection correction portion. of the form- inthe following manner:

(1) Enter in ' the registrationcorrected deflection (to'the nearest mil).

(2) Enterin [ the'regisjeqpng piecedisplacement correctionfrom LfJ(to thenearest mil).

(3) Algebraically add[7 and _[0 - todetermine the adjusted deflPion (to thenearest mil), and enter it in 9[J

13-12

13-10. IREGESTIRATEONPORTION

Section I of DA Form 4757 is used tocompute registration corrections for a firingunit

(fig 13-11). It is designed to computeachieved range, the displacement correction,and the deflection correction for theregistering piece when. the piece is.not overthe geographical battery center. A portion isprovided to record GFT settings andcomputer and hand-held calculatorregistration residuals.

a. Achieved Range. Use the achievedrange portion in the following manner:

(1) Enter in 17 the chart range to theregistration point to the nearest 10 meters).

0





FM 6-40

Figure 13-12. Section 11 f DA Form 4757.

13-11. HASTY CORRECTITONPORTION

Use section 11 of DA Form 4757 to computehasty corrections by platoon (fig 13-12).Enter the initial chart deflection, chart range,target number, and date-time group at thetop of section II.

a. DeflectionCorrections.

(1) A positive lateral correction is thenumber of meters left or right that eachplatoon center is from the GBC on the basis ofthe azimuth of lay. Determine this value byuse of the M10/M17 plotting board, and enterit in column a.

(2) A hasty position deflectioncorrection is the correction value applied tothe fire-for-effect adjusted deflection.Determine this value by entering the hastyposition deflection correction portion of theappropriate hasty special

correction table.Enter the table with the initial range andinitial platoon displacement (on the basis ofthe azimuth of lay) to the target. Extract theposition deflection correction, and enter it incolumn b.

b. Quadrant Corrections.(1) Enter in column c the platoon

Comparative muzzle velocity.

(2) Enter in column d the hasty MVcorrection factor extracted from the hastyMV correction portion of the appropriatehasty special correction table (app A). Enterthe table with the platoon comparative MVand the initial range to the target.

(3) The position range correction is thenumber of meters (forward or back) fromtheplatoon location to the platoon aiming point.

Determine this value by use of the M1O/M17plotting board, and enter it in column e.

(4) Enter in column f[the hasty positionquadrant elevation correction extracted fromthe hasty position quadrant elevationcorrection portion of the appropriate hastyspecial correction table. Enter the table withthe position range correction and the initialchart range.

(5) To determine the total quadrantelevation correction, add column d to columnf. Enter the total in column g.

c. Determination of Time.

(1) Enter in column h the correctedquadrant minus the fired site.

(2) Determine the time to firecorresponding to column h from theappropriate gage line. Enter it in column i.13-14



FM 6-40

13-12. SPECIALCORRECTIONPORTION

Use section III of DA Form 4757 to compute

special correctionsby gun or by platoon (fig

13-13). Enter the initial chart deflection,chart range, target number, and date-timegroup at the top of section III.

a. Deflection Corrections.

(1) Determine the position lateralcorrection from the platoon position to the

platoon aiming point by use of a properly

oriented M10/M17 plotting board. Enter the

correction in column a.

(2) Enter in column b the 100/R valuedetermined at chart range to the target.

(3) Compute the position deflectionapplied to the initial deflection to fire bymultiplying column a by column b and

dividing by 100. Enter the value in column c.

b. Quadrant Corrections.(1) Extract the platoon comparative

MVV from the battery MV logbook and enterit in column d.

(2) Enter in column e the MV correction

factorextracted from table F, column 10 or 11.

(3) Compute the range correction due to

muzzle velocity in column f by multiplyingcolumn d by column e.

(4) Determine the position range

correction from the platoon position to the

platoon aiming point by use of a properly

oriented M1O/M17 plotting board. Enter the

correction in column g.

(5) Determine the total range correction

in column h by adding columns f and g.

(6) Determine the position quadrantelevation correction in column i by dividing

the value in column h by the change in range

per 1-mil change in elevation extracted from

table F, column 5. Apply this value to theinitial quadrant to fire.

Figure 13-13. Section III of DA Form 4757.

13-15



FM 6-40

c. Determination of Time to Fire.

(1) Determine the corrected range incolumnj by adding the initial chart range tocolumn h expressed to the nearest 10 meters.

(2) Determine the time to fire by placingthe MHL over the value in column f. eadtime from the appropriate gage line.

13-43. PARALLEL SH[EAFa. Fire for Effect. All guns fire the

time, deflection, and quadrant computed bythe FDC on the basis of the chart datadetermined from the GBC and the targetcenter.

b. Adjust Fire. All guns fire the time,deflection, and quadrant determined by theadjustment when fire for effect was requestedby the observer.

13-14. CONVEJRGED SHEAFa. Fire-for-effect missions.

(1) Determine chart data (GBC to targetcenter) to the target.

(2) Determine initial firing data(deflection and quadrant) on the basis of thechart data (fig 13-14).

5i .L. 0 10caSi 000 Carr

b Cor Si +9j

71(.. 3 0

Figure 13-14. Initial firing data.

13-16





FM 6-40

o Determine the deflection correction.From the graphical firing table,etermine the 100/R value from theMHL at the chart range. Enter thisvalue on DA Form 4757, column b. Onthe form, in column c, determine

theposition deflection correction (fig13-16). Determine this value bymultiplying the position lateralcorrection by the 100/R value anddividing the product by 100. Apply theposition deflection correction to theinitial firing deflection.

Figure 13-16. Determing deflection correction and correcting the initial deflection.

13-18



FM 6-40

(b) Quadrant corrections. Determine

quadrant corrections as follows:

* Determine the muzzle velocity range

correction by extracting the platoon

comparative VE from the FDC muzzle

velocity logbook. Enter that value asan increase (I) or a decrease (D) to the

nearest 0.1 meter per second on DA

Form 4757, column d. Extract the MV

unit correction factor from table F,

columns 10 and 11, of the appropriateTFT, and enter it on DA Form 4757,

column e. Determine the rangecorrection due to platoon MV by

multiplying the platoon comparativeVE by the MV unit correction factor,and express the value to the nearest

meter (fig 13-17).Determine the position range

correction. This correction is thenumber of meters, forward or back,

that it takes to move a platoon center

from its location on the clear plasticdisk to the horizontal red line. Enterthis value (to the nearest 5 meters) on

DA Form 4757, column g (fig 13-18).

Figure 13-17. Determining range correction dueto muzzle velocity.

Figure 13-18. Recording the position range correction.

13-19



FM 6-40

o Determine the total range correctionwith the position range correction.

o Determine the quadrant correction byconverting the total range correction toa position quadrant elevationcorrection. Enter table F, column

5, ofthe appropriate GFT, and extract the

change in range for a 1-mil change inelevation. On DA Form 4757, dividethe total range correction by the valuefrom table F, column 5 (fig 13-19). Thequotient is the position quadrantcorrection. Apply that value

to theinitial firing quadrant.

Figure 13-19. Determining total range correction and quadrant correction and correcting theinitial. quadrant.

13-20



FM 6-40

(c) Time to fire. Determine time to fireas follows:

Add the total range correction (to thenearest 10 meters) on DA Form 4757,column h, to the initial chart range.

Place the MHL over the correctedrange and read time from theappropriate gage line (fig 13-20).

b. Adjust Fire Missions.

(1) Determine adjusted data to thetarget (fig 13-21).

Figure 13-20. Determining time to fire.

Figure 13-21. Adjust fire mission.

13-21





HASTYMUZZLEVELOCITY

M109A2/3 CORRECTIONS(M/S)M198

155-AM-2 -.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

M107 -.5 +1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0

RANGE H

MILS --0 0 - 1-1--"" 1'_._ -1T - "-

-1 -1 -1 - -12 -2 - 2 -3 -

2500 4GB +0 +0 +1 +1 +1+ +2 +3 +3 31 -1 -1 -2 -2 -2 -3 -3-3

250 4G 0 0+1+ +2 +3 "+3+

Figue3 2 4 . ast muzl velocity

+r+e +21 +2 +3+3+3

-1 -1 -2 -2 -2 -3 - -'-+0 + 1 + +2 +2 +3 +3 +4

-0 -1 -1-2 -2 - -3 -3 -4

600 +0+0 +_121+2+2 +3 +31 4I +4-1 2 3 -3 -4 -4 -5 -

650 B + + 1 +2 +2 +3 +3 ++

1 -- 2 3, - 4- .-

Figure 13-24. Hasty muzzle velocity

corrections

M109A2/3M198

155-AM-2M107

ANGE CHG

000o ,GB

500 4G B

z000 4GB

2500 4GB

3000 '4GB

.500- 5G B

3000 5GE

B500 5G(

FM 6-40

HASTYPOSITIONQUA NELEVATIONCORRECTIONS

(METERS)

20 140 607 8011001120 1401160118020

1 2 3 4 6 7 8 9 10 1

1 2 3 4 6 7 8 9 10 1

-1 -3 4 6 7 8 9 110 11

-1-T 3 4 6 7 819 10 I'

B 1 3 4 6 8 9 11 12 14 1

ME&.

Figure 13-25. Hasty position quadrant elevationcorrections table.

13-23

Figure 13-26. Applying hasty position quadrant elevation corrections.

m



TOTAL

QUADRANTLEVATtON

I- - - - -(D

Figure 13-27. Determining time to fire.

position to the quadrant correction formuzzle velocity. Add the quadrantcorrection to the adjusted quadrantand subtract site as shown in figure13-27.

(c) Time to fire. To determine time tofire for each platoon, subtract the site fromthe quadrant to fire (fig 13-27). Place theelevation gage line over the elevation, andread time to fire from the appropriate gageline.

13-15o SPECIAL SHEAFa. P l o t t i n g Grid, At t i t ude , a n dLength Targets. Target attitude is thegrid azimuth (0 to 3,200 mils) of the long axisof the target. The grid sent by the observer

isthe grid location of the center of the target.This grid is represented by the center rivet onthe plotting board. The target must be drawnto scale on the plotting board disk (fig 13-28)and must be in correct relationship to thedirection of fire (azimuth of lay 6350).(1) Orient the disk with the attitude ofthe target (1400) on the outer black scale

opposite the azimuth index.

(2) Using the same scale as the one onwhich the pieces are plotted, draw the targetto scale on the clear plastic disk. Over thevertical center line, draw a line starting one

Figure 13-28. Drawing a grid, attitude, andlength target.

13-24



FM 6-40

half the target length above the center rivet

and extend the line to one half the target

length below the center rivet.

(3) To place individual platoon aiming

points on a linear target, divide the length of

thetarget by the number of firing units

(platoons) minus one unit (fig 13-29).

(4) Set off the chart deflection to the

target (inner red scale) over the red index

arrow. The target is now graphicallyportrayed with respect to the line of fire.

Figure 13-29. Placing individual aiming points.

EXAMPLE:

The following call for fire is received:RECORD OF FIRE

CALL FR FIR

-- -- - "' -

6Observer ...H2 A .../s .. t .OO

' .- . "U IOV A

.12

000

i'olar-Dir __ -Dis -/P ____r_____VS t -. ir I. . . . ..

AIV i) ' 20 AA 0) *45 Q HOBSCorr

FIREORDEROfCorr Si

INIIA ........ .. ..........

.... .... ...

,..

Draw the target on the M1 plotting board as described in paragraphs 1), (2), and (3) above.The battery has three platoons (3 - 1 = 2). A 200-meter-long target divided by 2 equals 100

meters. Plot the first burst point at one end of the target, and then move toward the other end in100-meter increments. The last burst point should plot at the other end of the target. When the

initial azimuth of lay is 6,350 mils and the initial chart deflection is 3,207 mils, the plotting

board should look like that shown in figure 13-30.

RECORD O13-25

13-25





FM 6-40

Figure 13-32. Determining position lateral

corrections and recording the data.

* Determine deflection corrections asfollows:

Orient the M10/M17 plotting board.Place chart deflection (inner red scale)over the red index arrow.

Determine the position lateralcorrection from the platoon center tothe red vertical line that passesthrough the platoon aiming point.Enter this value (to the nearest 5meters) on DA Form 4757, section III,column a (fig 13-32).

Determine the deflection correction.From the graphical firing table,determine the 100/R value from theMHL at the chart range. Enter thisvalue on DA Form 4757, column b.

On DA Form 4757, column c,determine the position deflectioncorrection by multiplying the position

lateral correction by the 100/R valueand dividing the product by 100. Applythe position deflection correction to theinitial firing deflection (fig 13-33).

13-27

Figure 13-33. Determining the deflection correction and applying it to the initial deflection.



FM 6-40

0 Determine quadrant corrections asfollows:

Determine the muzzle velocity rangecorrection by extracting the platoonpomparative VE from the FDC muzzleelocity logbook. Enter the value as anincrease (I) or a decrease (D) to thenearest 0.1 meter per second on DAForm 4757, column d. Extract the MVunit correction factor from table F,columns 10 and 11, of the appropriateTFT, and enter the value on DA Form4757, column e. Determine the rangecorrection due to platoon comparativemuzzle velocity by multiplying theplatoon comparative VE by the MVunit correction factor. Express the MVrange correction to the nearest meter(fig 13-34).

Determining the muzzle velocityrange correction.

Determine the position rangecorrection. This correction is thenumber of meters (forward or back)that it takes to move a platoon centerfrom its location on the clear plasticdisk to the horizontal red line thatpasses through the platoon aimingpoint. Enter the value (to the nearest 5meters) on DA Form 4757, section III,column g.

Determine the total range correctionby adding the MV range correction tothe position range correction (fig13-35).

Determine the correction toquadrant by converting

the total rangecorrection to a position quadrantelevation correction (fig 13-36). Entertable F, column 5, and extract thechange in range for a 1-mil change inelevation. Divide the total rangecorrection by the value from table F,column 5. The quotient is the positionquadrant correction. Apply that valueto the initial firing quadrant.

RANGE TARGET

PLATOON MUZZLE MUZZLE POSITION TOTALOMPARATIVE VELOCITY VELOCITY RANGE RAG

ERROR CORRECTION RET SNiFORWARDS M0 CREASE FACTOR (BACK (ECREASE1i TABLE e.0

APPROPRIATE T,

DECREASE-.INCREASE

1METERT

PER ECONO 0 0RMETR M

Figure 13-35. Determining the position rangecorrection.

o Determine time to fire as follows:Determine the corrected range by

adding the total range correction (tothe nearest 10 meters) on DA Form4757, column h, to the initial chartrange.

Determine the time to fire by placingthe MHL over the corrected range andreading time from the appropriategage line (fig 13-37).

13-28

Figure 13-34.



PLATOONCOMPARATIVEVELOCITYERROR(INCREASEDECREASEI

0 METERPER ECOND

MUZZLEVELOCITYUNITCORRECTIONFACTOR

iTABLE FAPPROPRIATE Tl

DECREASE-INCREASE

0 1 METER

r ,.o 4-49

0 o i " .3

MUZZLEMUZZLEVELOCITYRANGE

CORRECTION

0-.

I METER

0

POSITIONPOSITIONRANGE

CORRECTIONIFORWARDiRACK

5 METERS

TOTALROAG

CRRNECTO

0 G

I METER

QUADRANTELEVATIONCORRECTION,(D- COLUMN

TABLEAPPROPRIATE b+

I MIL

7,3

urw- r rCF,$N,3 rOwtDf Cur Of Chen NOB .~Tp

Dk,Fl Dew Eg Cbj IsChg: er _DI_ - _____ c r1 h____ ___..__._......... ..__...()..red..g....

_..-..-...

__.ZIZ ..A Z.......- -.........-.-...... _.....3 K iZ..

Figure 13-36. Determining and applying the correction to quadrant.

TARGET DATE TIME ROUP

MUZZLE POSITION TOTAL POSITION CORRECTED TIMF (

VELOCITY RANGE RANGE QUADRANT RANGE FIRF

EORRECTION CORRECTION ELEVATIONFUZE

CORRECTIONRFORWARD 1LCORRECTION0' SECTING0EF O W R Q IDOMETERS 0._RBACK I0 - COLUMN . INITIAL

TABLE RANGEAPPROPRIATE Ti

.... h

1 METER N METERS 1 METER I MIL 10 ETERS 01

. ... UY -n ,=

_ ' _ 0. 0.

Dir, MU DeR IaFS

Cerr

_ _ _ _ F t F 1 1 0 1-... - 0, .

..... . . =- .....r-..-.

. . . ................ . ......... ....................................... ................... ....................... ....................................................

I- ZW;~..I~i~i~-1aFigure 13-37. Determining time to fire.

13-29

FM 6-40

I7- mmx

rffiodEl ..

MgIIi:.; A n I• A I L -I% n e t2

.......... .,

,-. ...........

.....,.. .

..... ... . .

wel cbI.",

..........

11E OMMANDSL oL .. I

mm

I

1--iEd-

1f, I cht of

chwt MODto -t C*rr



FM 6-40

b. Plotting Two-Grid Targets.(1) When a target is described by tw o

grids by the observer, the location of thecenter grid of the target must be computed toallow determination of chart range and chartdeflection to only one point. Thiscomputation also allows the center

of thetarget to be represented by the center rivet.Using grids 168198 and 171196, determinethe center grid. The center grid can bedetermined very rapidly by inspection by useof the following procedures:

(a) Determine the difference ineastings announced by the observer.

17100-16800

300 meters16800 numerically smaller

easting+15016950 easting to center of target

(d) Perform steps (a) and (b) above fornorthing.

19800-19600

200 meters200 - 2 = 100 meters

(e) Add 100 meters to the numericallysmaller northing. The resulting value is the

northing to the center of the target.19600 numerically smaller northing

+10019700 northing to center of target(f) The center grid to the target is

16950 19700.

(2) Determine the difference in eastingand northing from the target center to thegrids sent by the observer.

(b) Divide the 300 meters by 2.

300 - 2 = 150 meters

(c) Add 150 meters to the numericallymaller easting. The resulting value is theeasting to the center of the target.

EASTING NORTHING

Target centerTarget gridDifference

16950

16800

15 0

19700

19800

100

(3) Visualize the attitude the tworequested grids would form on a map (fig13-38).

Figure 13-38. Visualizing the attitude ofthe target.

(4) Orient the disk with the 0 (outerblack scale) opposite the azimuth index. Thisorients the clear disk north. The center of theplotting board represents target center grid;for example, 1695 1970.

(5) On the plotting board, measure thedifferences in easting from the center rivetalong the center horizontal line.

(6) On the basis of visualization of thetarget attitude, measure the differences innorthing along a line parallel to the centervertical line. Make marks on the clear plasticdisk at those points. The target grids sent bythe observer are now portrayed on theplotting board.

(7) Connect the two plotted points bydrawing a straight line through the center ofthe plotting board. The target has now beendescribed on the clear plastic.disk (fig 13-39).

13-30

S



FM 6-40

Figure 13-39. Plotting a two-grid target.

(8) Rotate the disk until the targetdescribed on the disk is over the centerhorizontal or vertical line on the base. Thisprovides a scale to mark off the distancebetween bursts along the target. For placingbursts on a linear target, see paragraph13-15a(3).

(9) Now compute special corrections asdescribed in paragraph 13-12.

c. Plotting Three-Grid Targets. Whenthe observer describes a target with threegrids (the middle grid represented by thecenter rivet on the plotting board), use thefollowing procedures:

(1) Orient the disk to grid north (fig13-40). Place the 0 (outer black scale) oppositethe azimuth index.

(2) Determine the differences in eastingand northing of the middle grid and thetarget end point grids. For example, use grids168197, 169198, and 170197.

(3) Plot the differences in easting andnorthing for each leg of the target from themiddle grid on the plotting board. Ploteasting parallel to the center horizontal lineand northing parallel to the center verticalline.

Figure 13-40. Plotting a three-grid target.

(4) Connect each plotted point to thecenter of the plotting board with a straightline.

(5) Determine the total target length byrotating the disk until one of the constructedlines of the target on the disk is over the

center vertical or horizontal line on the base.This provides a scale to measure the length ofthat target leg. Measure the other target leg inthe same manner to determine the totallength of the target.

(6) Use the total target length to placeplatoon aiming points. Determine and markthe distance between the aiming points. Forplacing bursts on a linear target, seeparagraph 13-15a(3).

13-31



FM

(7) Orient the plotting board by settingoff the chart deflection to the middle grid(inner red scale) over the deflection index tographically portray the target in relation tothe line of fire. When using a chart deflectionof 3,600 mils over the deflection index, the

target should look like the one shown infigure 13-41.

red index arrow. Measure up from the centerrivet one half the target radius, and place adot at that point. Perform the same procedureat azimuths 2130 and 4260. This proceduregives the circle three platoon aiming points(fig 13-42).


i

Figure 13-41. Target in relation to the azimuth

of fire.


d. Plotting Circular Targets With aRadius Greater Than 100 Meters. Whenthe observer describes a circular target thathas a radius greater than 100 meters, use thefollowing procedures:

Note. The grid identified in the call for fireis represented by the center rivet.

(1) Draw the target on the clear plasticdisk by measuring, from the center rivet, theradius of the target along the center verticalline. Holding your pencil at that point, spinthe clear plastic disk 6,400 mils, describingthe target on the plastic disk.

(2) Identify the platoon aiming points.Orient azimuth 0 (outer black scale) over the

Figure 13-42. Circular target with a radiusgreater than 100 meters.

13-16. FADACPosition correction procedures with

FADAC are in the FADAC job aids.

13-17. BATTERY COMPUTERSYSTEM

The battery computer system determinestrajectories for each firing piece to individualpiece aiming points.

13-10. HAND-HELDCALCULATOR

The hand-held calculator can be used toexpedite the mathematics required in theregistration/special correction work sheet.

13-32

I - -A - AL-,i g = M

L

1 7 r"wr TV I I Wf lirm l p I vv 11 ppr F FF m T, w.

6-4o0





FM 6-40

(2) If the subtargets described abovehad required further subdivision (forexample, sweep and zone), the battalion FDOcould have designated how the batteries wereto attack the target.

FIRE FOR EFFECT, BATTALION,ALPHA GRID 632366,BRAVO GRID 630363,CHARLIE GRID 629361,ATTITUDE 365, DPICM 4 ROUNDS,SWEEP AND ZONE, TIME ONTARGET.

(3) As an alternate method, the FDOcould have said:

FIRE FOR EFFECT, BATTALION,ALFA GRID 632366,BRAVO GRID 630363,CHARLIE GRID 629361,ALTITUDE 650, ATTITUDE 365,PLACE BURSTS 65 METERS APART,DPICM , 4 ROUNDS, TIME ONTARGET.

This indicates to each battery not only thecenter grid but also the type of sheaf(indicated by a width of 65 meters betweenpiece aiming points) they are to fire.

c. The linear target table may be used todivide linear targets into battery or two-gunplatoon subtargets. Table 13-1 is used for the

155-mm howitzer, but a table may beconstructed for any caliber or configuration.The first column lists the target length. Thesecond column lists the number of meterseach battery must add or drop along the longaxis of the target to determine the end-pointgrid for its subtarget. The third column liststhe interval between platoon targets.

EXAMPLE:The battalion FDC receives the followingcall for fire:

D26 THIS IS D12,FIRE FOR EFFECT, OVER.GRID 938182, OVER.INFANTRY IN TREE LINE,

LENGTH 800, ATTITUDE 1900,OVER.

(1) The chart operator plots the targetand orients the target grid along the attitudeof the target.

(2) All computers ensure that eachbattery has monitored the call for fire, or theypass the call for fire to the battery.

(3) Each battery chart operator alsoplots the target and orients the target grid.

(4) The battalion FDO examines theplot and, on the basis of the attitude of the

Table 13-1. Linear target table-155-mm howitzer.

TARGET LENGTH(METERS)

1,5001,4001,3001,2001,1001,000

95090085 080075070065060055050 0

NUMBER OFMETERS +/-

70065 060055 050045042540037 535 0325300275250225200

PLATOONINTERVAL

165150140130

12011010010 0

9085807570655550

I50

13-34

S



FM 6-40

target with reference to the position of thefiring batteries, determines that Battery Cwill attack the left portion of the target,Battery B will attack the center of the target,and Battery A will attack the right portion ofthe target. Using the linear target table, theFDO determines the number of meters abattery will add or drop and the platoonaiming point interval. He then issues the fireorder.

FIRE FOR EFFECT, BATTALION,

ALFA, LEFT PLATOON, DROP 350,

INTERVAL ADD 85;

BRAVO, CENTER PLATOON,INTERVAL 85;

CHARLIE, RIGHT PLATOON, ADD

350, INTERVAL DROP 85;ALTITUDE 370,3 ROUNDS, TIME ON TARGET.

(5) The Battery C chart operator drops350 meters along the attitude and announcesthe chart data for the left platoon. He adds 85meters and announces the data for the centerplatoon. He then adds another 85 meters andannounces the data for the right platoon.

(6) The Battery B chart operator

announces the chart data to the announcedgrid for the center platoon, adds 85 meters,and announces the data for the right platoon.He drops 85 meters from the center of thetarget and announces the data for the leftplatoon.

(7) The Battery A chart operator adds350 meters along the attitude and announcesthe chart data for the right platoon. He thendrops 85 meters and announces the data fromthe center platoon and drops another 85meters and announces the left platoon.

13-21. MASSED FIREDeSTIREIBUTr ONTEMPLATE METHOD

Large or irregularly shaped targets areplotted on the firing chart by the massed firedistribution template method. A locallyconstructed massed fire distribution templatedrawn to scale for the firing chart is placed

over the plotted target to allow the user todetermine the optimum aiming points for therequired number of firing elements to massfires.

a. Constructing he Template. Over-lay paper is the best material for constructingthe template. Each tick mark placed on thetemplate represents an aiming point for afiring element (fig 13-44). A separatetemplate is required for each caliber,munition type, and size of firing element (onegun, platoon, or battery). The distancebetween tick marks is based on the radius ofeffects of the particular weapon system andmunitions to be fired. Refer to FM 101-60-17(C) and the appropriate JMEM. Each tickmark represents the center mass of roundsfired by a firing element (weapon, platoon, or

battery).

10@+ + + + + + + +

8+ + + + + + ++t+ + + + + + + + +

1+ + + + + + + + +

S+ + + + + + + +4 + + + + + + + + +3 + -- + + + + + -"---++2 + + + + + + + + +I1+ + + + + + + "-++

A B C D I : G H I

Figure 13-44. Example of a high-explosivedistribution template.

b. Using the Template. Place thecenter tick mark (E-5 in fig 13-44) over thecenter of the target or the nearest gridintersection. Orient the template north-southor east-west. Then determine the pointswithin the target area to attack.

13-22o SWEEP AND ZONEFHRES

In rare instances a battery (or a 3x8platoon) may fire alone on a large target onwhich sweep and/or zone fires are required.Surprise is lost as multiple volleys are fired.The fire unit may also be in greater danger of

13-35



FM 6-40

being located by enemy target acquisitiondevices. When firing sweep or zone fires, eachplatoon will first be assigned an aiming pointby use of special sheaf techniques. Thenmanual computations can be done todetermine the number of additional sets of

firing data for the sweep or zone fires. Sweepor zone techniques cannot be controlledeffectively for units occupying large areasunless the special sheaf technique is appliedbefore sweep or zone instructions areassigned. These techniques parallel the BCSprocedures for computing sweep and zonefires.

a. Sweep Fire. When the target is wideenough (in relation to the direction of fire),sweep fires may be used. In sweep fire, theweapons fire constant quadrant elevationswith

several different deflections (fig 13-45).

I____

IDIRECTION

OF FIRE

-TARGET WIDTH = 750 METERS 1

TARGET WIDTH NUMBERMUNITIONS OF

BURST WIDTH DEFLECTIONS

Figure 13-45. Example of sweep fire for athree-platoon battery.

N o t e . The above table is based onunclassified data from FM 6-141-1.

(1) Determine the total number ofdeflections to be fired. Divide the width of thetarget by the munitions effective burst width.Express the value to the next higher wholenumber. This value is also the number ofrounds to fire.

Table 13-2. Munitions effective burstwidths.

CALIBER

105 mm

155 mm

203 mm

MUNITIONTYPE

HE1CM

HE

APICM

DPICM

HE

APICM

DPICM

EFFECTIVEBURST WIDTH

(METERS)

3035

50

60

50

80

70

80

(2) Determine the sweep (in mils).Divide the effective burst width by the rangeto the target (in thousands).

Munitions effective burst width = sweep (in mils)Range to target (in thousands)

EXAMPLE:An M109A3 battery is occupying a very largeposition. The FDC receives an urgent call orfire on a target 750 meters wide and 25 0meters deep along the direction of fire. Noother fire units are available to mass. TheFDO decides to attack the target withplatoon special sheaf and sweep fires by useof HE rounds.

Given:

Range to thecenter of thetarget

Deflection to thecenter of thetarget

5,000 meters

3,218 mils

The FDC assigns pldtoon aiming pointsalong the target center line, perpendicular othe line of fire. The FDC determines thenumber of deflections to be fired.

Target widthMunitions effective burst width

= 750 = 15 deflections50

The FDC determines the sweep (in mils).

Effective burst width

Range to target (in thousands)

50 = 10 mils5

13-36



FM 6-40

(3) Fire commands for sweep fire areas follows:

BATTERY (so many) ROUNDS,SWEEP (so many) MILS,(so many) DEFLECTIONS, CHARGE(so and so)

Deflection and quadrant are also announcedfor each platoon. The weapons fire thedeflection and quadrant announced in thefire command first. The remaining data arefired according to the order stated in unitSOP.

b. Zone Fire. When the target is deepenough in relation to the direction of fire, zonefires may be used to attack the target. In zonefire, the weapons fire constant deflections

with several different elevations (fig 13-46).

DIRECTIONOF FIRE

TARGET DEPTH =

750 METERS

Figure 13-46. Example of zone fire for athree-platoon battery.

(1) Use special sheaf techniques toassign aiming points on a line perpendicularto the direction of fire from the center of thefire unit to the center of the target.

(2) Determine the total number of QEsto be fired. Divide the depth of the target bythe munitions effective burst width. Expressthe value to the next higher whole number.

Target depth . =toaQstofrMunitions effective -toaQstofrburst width

(3) Determine the mil change for zonefire.

(a) Add the value of the munitionseffective burst width to the range to the targetcenter.

(b) Determine the QE for the rangedetermined in (a) above.

(c) Determine the QE for the range tothe target center.

(d) Subtract the QE for the centerrange of the target from the QE determined inparagraph (b) above. The results are the zonemil change.

(4) Announce zone fire in the firecommands as follows:

BATTERY (so many) ROUNDS,ZONE (so many) MILS,

(so many) QUADRANTS,CHARGE (so and so), DEFLECTION(so and so), QUADRANT ELEVATION(so and so)

Deflection is announced for each platoon.The weapons fire the deflection and QEannounced in the fire command first. Theremaining data are fired according to theorder given in unit SOP.

EXAMPLE:

An M1 09A3 battery is occupying a very largeposition. The FDC receives an urgent call forfire on a target that is 750 meters deep and250 meters wide along the direction of fire.No other fire support means are available.The FDO decides to attack the target withplatoon special sheaf and zone fires by use ofHE rounds. Charge 4GB is being ired, and acurrent GFT setting is in effect.

Given: Range to the center of the target is5,000 meters and site is x4 mils. The FDCassigns platoon aiming points along thetarget center line. The FDC determines thenumber of quadrants to be fired.

Target depthMunitions effective burst width

750= y =15 quadrants

Munitions effective burst width

The FDC determines the mailchange for zonefire.

13-37



Munitions effectiveburst widthRange to target

50 meters+ 5,000 meters

5,050 meters

,QE corresponding o range 5,050 meters

elsiQE

328+4332

QE corresponding o range 5,000 meters

elsiQE

323+4327

Difference in QEs

332-327

5 mils

Therefore each weapon will fire QE 327 and sevenQEs over and seven QEs short of QE 327 in 5-milincrements.

362 357 352 347 342 337

Quadrant elevation:

332 E l 322 317 312 307 302 297 292

c. Combination Sweep and ZoneFires. When very wide and very deep

targets are to be attacked by one fire unit, acombination of sweep and zone fires can beused.

Section IVFINAL PROTECTIVE FIRE

13-23. DESCRIPTIONA final protective fire is an immediately

available, prearranged barrier of firedesigned to protect friendly troops andinstallations by impeding enemy movementsacross defensive lines or areas. The normaluse of FPF is to establish prearrangedclose-in defense. This defense includes otherartillery fires, minefields, obstacles, finalprotective machine gun lines, small arms fire,and mortar final protective fire. Each battery

can be assigned one FPF and normally is laidon the FPF data when not firing othermissions. The FPF may be fired on aprearranged signal or fired on call from thesupported unit. An FPF may be repeated oncall as often as necessary. When time,ammunition, and the tactical situationpermit, the data for the FPF may be verifiedor corrected by the firing of check rounds. Abattery FPF may be fired either individuallyor in coordination with the FPF of otherbatteries.

13-38

FM 6-40



FM 6-40

a. Width (or Length) of the FinalProtective Fire. The width (or length) ofthe FPF that can be covered by a singlebattery without shifting its fire should notexceed six effective burst widths of the typeammunition to be fired. When necessary, theartillery commander and the commander ofthe supported unit may agree to increase thewidth of the final protective fire. However,increasing the width of the FPF will decreasethe effectiveness of fire.

b. P r e p a r a t i o n and Update ofData. The actual grid location and attitudeof the FPF are reported by the FIST. Since theFPF usually is located within a very shortdistance of positions occupied by friendlytroops, precise computational procedures

mustbe used, and all available corrections

must be applied. Special corrections in theform of calibration corrections and positioncorrections, obtained by use of the M17plotting board, are determined and applied asindividual piece corrections. It is critical thatFPF data be constantly updated withchanges in met, propellant temperature, andprojectile and propellant lots. The FPF datamust also be updated when survey is updatedor when more current registration databecome available for the ammunition,charge, and angle of fire to be used in the final

protective fires.

c. Ballistic Computers. Ballisticcomputers are also used for computation offinal protective fire data. See the appropriatejob aids for a more detailed discussion.

13-24. MANUALCOMPUTATION OFDATA WITH THE GFTOR TFT

a. Observer-Adjusted Final Protec-tive Fire. In an observer-adjusted FPF,the observer adjusts the center weapon in thebattery onto the center point of the FPF line.The adjusted data are used as the initialfiring data to apply special corrections asdescribed in section II. Each individual pieceshould be adjusted if time and the tacticalsituation permit.

b. F i n a l Pro tec t ive F i r e NotAdjusted. When the situation does notpermit the adjustment of the center weapononto the center point of the FPF line, the FD Ccomputes special corrections for each weaponto an aiming point on the FPF line asdescribed in section II.

Section VOBSERVERS

13-25. AIR OBSERVER

CONSIDERATIONSAir observers (AO) often encounter three

problems that require special assistance fromthe fire direction center.

a. The AO seldom has a fixed direction tothe target. Normally, he is flying up anddown, in and around the target area.Therefore, FDC personnel must be preparedfor unusual and changing observer directionsor spotting lines. Every adjustment willprobably have a different observer direction.

b. The AO may lose his perception ofdistances while in the air. He may request

ranging rounds (two rounds impacting 400meters apart) as an aid to visualizingdistances in the target area. The observer andthe FDC personnel must realize that rangingrounds fired along the gun-target line maydisclose to the enemy the firing unit's generallocation.

c. The AO must minimize the time he isexposed to enemy detection. In forward areas,the pilot must fly close to the earth andbehind cover as much as possible. The AO

13-39



FM 6-40

and his pilot therefore require from the FDCvery accurate time of flight, shot, and splashso that the pilot can unmask the aircraft 2 to 3seconds before the round impacts.

13-26. OBSERVERDIRECTIONS/SPOTTING LINES

a. Grid Coordinates and Gun-TargetLine. If the AO knows the location of thefiring unit in relation to the target, he maychoose to adjust along the gun-target line.When he announces DIRECTION,GUN-TARGET LINE or implies GT line byhis omission of a direction, the chart operatorplots the target and

centers the target gridalong the arm of the RDP over the target.This sets up the GT line on the chart.

b. Shift From a Known Point Alongthe Gun-Target Line. The AO maydesignate DIRECTION, GUN-TARGETLINE for a shift from a known point. In thisinstance, the chart operator plots the knownpoint, centers the target grid, and orients itfor the gun-target line. The chart operatorplots the AO's shift and determines chartdata. He then rotates the target grid aroundthe new pinhole so that the

arrow is parallelto the gun-target line (the arm of the RDP).

c. Cardinal Direction. The AO maychoose to adjust along a cardinal direction(one of the eight principal points of thecompass) (fig 13-47). The RPV will always

00 OR 36000 OR 6,400 MILS

3150 OR 450 OR5,600 MILS 800 MILS

NNW NE

2 70 0 0OR W E 900 OR4,800 MILS 1,600 MILS

SW SE

2250 OR 1 35 0 0OR4,000 MILOS2.400 MILS

800 OR 3.200 MILS

Figure 13-47. Cardinal direction.

use grid north to adjust rounds. When the AOannounces a cardinal direction, the chartoperator converts the direction into mils andorients the target grid to that direction.Direction southwest (SW) is converted todirection 4,000

mils by the fire directioncenter. The AO may also shift from a knownpoint by use of a cardinal direction.

d. Helicopter Instrument Readingsfor Direction. When the AO's aircraft ischanging locations and popping up anddown and in and around the target area, hemay use the aircraft instrument readings forhis observer direction. Since this direction isexpressed in degrees, FDC personnel mustconvert the reading to mils by use of thefollowing relationship:

Direction in degrees x 17.8 = direction inmilsDirection: 2502500 x 17.8 mils = direction 4,450 mils

Note. In preparation or AO missions, thechart operator should mark a target grid indegrees or prepare a conversion chart forquick conversion from degrees to mils.

e. Spotting Line. The AO may adjustalong lines formed by natural or man-madeterrain features such as roads, railroads,canals, or ridge lines. Prior to flight, ifpossible, the AO selects the line, determinesthe direction, and notifies the fire directioncenter. While in flight, he may select a linethat is readily identifiable and convenient.The AO may describe the feature in detail andhave FDC personnel determine the directionfrom a map by use of a protractor. The chartoperator orients the target grid on thatdirection.

13-27. RANGING ROUNDSIn his call for fire, the AO may announce

REQUEST RANGING ROUNDS. Thisindicates that he desires to see a volley of tworounds that impact 400 meters apart atrelatively the same time. Ranging rounds arefired only as a last resort. They are fired alongthe gun-target line (fig 13-48). The chartoperator determines initial chart data, and

13-40



FM 6-40

Figure 13-48. Ranging rounds.

the computer determines initial firing datafor the adjusting piece. The computer thenadds 400 meters to the announced chartrange. Using the new range and the initialchart deflection, the computer determinesfiring data for the second piece to fire in thevolley (usually, the other piece in the centerplatoon). The ranging rounds are firedsimultaneously by firing AT MYCOMMAND. When the AO observes theimpact of the rounds and determines thecorrections necessary to hit the target, he

J TARGET

I. DIRECTION: GUN-TARGET:1 .LINE FROM THE NEAR

+200 \ M.ROUND LEFT 100, ADD

200.

L1 00

N BATTERY

Figure 13-49. Adjusting from a ranging round.

may base his corrections on whichever roundlanded closest to the target. He must specifyto the FDC from which round he is adjusting,and the chart operator plots the shiftaccordingly (fig 13-49).

13-28. TIME OF FLIGHT/SHOT/SPLASH

In the message to observer, the FDC mustspecify the time of flight. On all volleys, theFDC must promptly announce SHOT andSPLASH. The FDC should be watchful forchanges in the time of flight as the missionprogresses.

13-29. COMPUTERPROCEDURES

Direction in degrees must be converted tomils. When firing ranging rounds, theFADAC procedures parallel those forillumination range spread. If the GT lineoverride is left enabled, the FADAC willcompute and use a new GT line for eachsubsequent correction. Normally, the first GT

line computed (with the initial round) shouldbe used throughout the mission. See theappropriate job aids for a discussion.

13-30. UNTRAINEDOBSERVERS

Calls for fire from untrained personnelacting as ground observers require closeattention and initiative from FDC personnel.The FDC personnel must be prepared toassist the untrained observer in his call forfire and adjustment of artillery.

a. The FDC personnel must take theinitiative if the observer is hesitant orconfused in his request for fire support. Theymust ask leading questions such as thefollowing:

(1) Where is the target?

(a) What are the grid coordinates ofthe target?

13-41



FM 6-40

(b) Where is the target in relation to areadily identifiable natural or man-madefeature?

(c) What is your location? How far isthe target from your location and in whatdirection?

(2) Is the target personnel, vehicles,armored, or wheeled?

(a) What is the size of the enemyforce?

(b) What are they doing at present?(c) If they are moving, which way are

they headed? How fast are they moving?

(3) How close is the target to you? Ifthey are within 600 meters or closer to otherfriendly troops, the observer

must "creep" therounds to the target.

(4) What is your direction to the target?(a) What is the azimuth in degrees or

mils?

(b) What is the cardinal direction (N ,NE, E, SE, S, SW, W, NW)?

(c) Is the direction along a natural orman-made feature?

(5) What effect on the target do you

need?(a) Is the target shooting at you?(b) Is it necessary to obscure the

target's vision?(c) Do we need to neutralize the target

or destroy it?

b. Explain to the observer what artilleryfire he is getting.

(1) You will see one round that will looklike a cloud of dust. You will get-more roundswhen you move the burst within 50 meters orso of the target.

(2) The round is now on the way andwill impact in 10 seconds.

c. Help the observer make corrections.The FDC personnel must help the observermove the rounds to the target and must beprepared for unusual shifts or combinationsof shifts. To obtain corrections, they shouldask leading questions such as the following:

(1) Where did the round(s) land inrelation to the target?

(a) Did it land left or right? Howmuch?

(b) Did it land over or short? Howmuch? (Ask for dimensions in meters or in thenumber of football-field lengths.)

(2) Did the round land closer to thetarget than the previous round?

d. Use sound judgment. The FDCpersonnel must decide whether or not torequire the observer to authenticate hismission. They must be on the watch forpossible observer misorientation. Also, FDCpersonnel must help the observer determinewhen a satisfactory effect on the target hasbeen achieved. In all cases, the FDC musttake the initiative in these situations.

Section VIWRNE-TO-ZOI IE TI I$FO I:I

13-31. DESCRIPTIONa. Zone-to-zone transformation is the

method used to change coordinates and/orazimuths of one zone to coordinates and/orazimuths of the adjacent zone.

b. In the universal transverse mercator(UTM) grid system, there are several areas

around the world in which artillery units mayhave to fire across UTM zone junctions.When this occurs, it is necessary to transformthe grid coordinates of points and gridazimuths of lines of one zone to those of theadjacent zone.

c. Figure 13-50 shows two adjacent UTMzones-14 and 15. The coordinates for

©13-42



FM 6-40

in the 14th zone are 800370. If 9 were to beexpressed in the terms of zone 15, itscoordinates would be much different. Thesame situation exists in terms %f directionfrom point 0 to trig marker ( . In zone

14, it is obviously different from what it wouldbe in zone 15.

d. Zone-to-zone transformation can be

accomplished by the following three means:

(1) Cutting and joining two grid sheets.

(2) Using the graphic method.

(3) Using the computation method.

e. Maps printed by the Army map serviceshow the differences between UTM gridzones. Maps that cover an area within 25

miles of a UTM zonejunction are printed with

two sets of grid line numbers around theborder-one set for each zone. One set isprinted in black; the other set is printed inblue and corresponds to the adjoining gridzone. Marginal information on the maps alsoindicates the color that applies to each zone.

UNIVERSAL TRANSVERSE MERCATOR

ZONE JUNCTION

C M CM

4343

42 42lZONYE 14--

N ZONYE 1,5..

41 41

40 40

39 39

38 38

373700,000

76 77 7 8 9 7 9 0 80 1 2 3 4 500,000

ZONE 14 ZONE 15

Figure 13-50. Adjacent universal transverse mercator zones.

13-43



FM 6-40

UNIVERSAL TRANSVERSE MERCATORZONE JUNCTION

94 95 96 97 9°

__ -67

- -66

_"__ -65

- 64

- 63

62

61

42 43 44 45 46 47 48 49 50NOTE: NOT TO SCALE ADJACENT ZONE PRIMARY ZONE

Figure 13-51. Joining two grid sheets.

13-32, CUTTING ANDJOINENG TWO GRIDSHEETS

The fastest and simplest method ofzone-to-zone transformation is cutting andjoining two grid sheets. Two grid sheets areprepared and joined to form a large chart (aconstructed grid sheet) from which chart dataacross the zone junction can be determinedautomatically (fig 13-51).

a. Preparat ion of Grid Sheets. Thechart operator prepares a piece of chart paper(a grid sheet) for each grid zone involved.Using a plotting scale and a sharp pencil, thechart operator reproduces on the grid sheetsthe exact orientation of the zone junctionlongitudinal and latitudinal lines as theyappear on the map(s) of the area of overlap.The edges that are to be joined should bemarked with a fine line on the basis of

accurate measurements taken from themap(s). Care should be taken in cutting andtaping so that when the sheets are puttogether to form one large chart,measurements from this large chart can bemade accurately.

b. Use of the Cons t ruc ted GridSheet. When firing data are determinedfrom a constructed grid sheet, notransformation or

computations arenecessary. The coordinates are measured andplotted from the grid lines for the respectivearea. The observer's azimuth is used asannounced, and the target grid is emplacedby using grid north of the observer's zone.

13-33. GIRAPHIC METHODa. Des igna t ion of the P r i m a r y

Zone. Either of the UTM zones may be

13-44

S



FM 6-40

designated as the primary zone. Designationof the primary zone is based on the tacticalsituation, unit SOP, the directives of thecommander, or the anticipated location offuture operations.

b. Preparat ion f the Map.

(1) After the primary zone has beendesignated, the map of each zone should beprepared for transformation. If two maps areused, they are lined up along the commonUTM zone junction longitudinal line.

(2) The FDO and a chart operator,using the arm of the RDP or a longstraightedge, trace the grid lines of theprimary zone into the secondary zone on themap.

(3) The east-west grid lines of theprimary zone are extended by use of the tickmarks around the border and are numberedwith the appropriate values. The north-southgrid lines are constructed similarly. Thesuperimposed grid lines should be drawnwith a colored pen to facilitate the rapidtransformation of data and to reduce thepossibility of errors.

c. Determination of Chart Data.

(1) Number the firing chart with thenumber designations of the grid lines of theprimary zone.

(2) When the call for fire is received and

the observer's target location lies in theadjacent zone, plot the target location on themap by using the normal grid lines of theadjacent zone.

(3) Using the superimposed grid lines ofthe primary zone, determine a new set ofcoordinates for the target. Plot the newcoordinates on the firing chart, anddetermine chart data by use of standard firedirection procedures.

(4) For adjust fire missions, the next

stepis to convert the observer direction in the

secondary zone to the corrected direction inthe primary zone. In this case, the observerhas not done this previously using his ow nmap.

(5) Compute the correction factorapplied to the observer's direction by use oftable 14 of the current Army Ephemeris (fig13-52).

Figure 13-52. Extract of table 14 of the Army Ephemeris.

13-45



FM 6-40

(a) Using the superimposed gridlines, determine the northing coordinate(seven significant digits) of the target in theprimary zone. Also, using the printed gridlines, determine the northing coordinate ofthe target.

(b) Add the values of the coordinates,and divide the sum by 2 to obtain the averagenorthing.

EXAMPLE:

Primary grid from map 5551650Secondary grid from FO. +5552100

11103750

11103750z" 2 = 5551875

(c) Using theaverage northing andthe latitude of the target at the nearest listed

value, enter table 14, column N. Find thecorrection factor, in mils, in cojumnC, Thelisted value nearest 5551875 is 560000. Thecorrection factor is 45.598.

(d) Express the correction factor tothe nearest 10 mils (45.598 50), and apply itto the OT direction using the following rules:

0 When the point is transformed in theNorthern Hemisphere from east towest, the sign is (-). When the point is

transformed from west to east, the signis (+).o When the point is transformed in the

Southern Hemisphere from east towest, the sign is (+). When the point istransformed from west to east, the signis (-).

(e) If the observer is in the SouthernHemisphere, subtract the average northingcoordinate from 10,000,000 before enteringthe table.

(6) Use the corrected direction to orientthe target grid, and determine the chart datafor the adjustment using standard firedirection procedures.

EXAMPLE:East to west transformation-change ignto minus (-).

Direction (azimuth)Correction actorCorrected direction

1 870 mils+ (-50)1,820 mils

d. Observer in the Secondary Zone.With Battery in the Primary Zone.

(1) Polar plot. A corrected directionmust be determined before the target locationon the firing chart is plotted. The northingcoordinates of the observer's location in bothzones are used to determine the averagenorthing.

(2) Shift from a known point. Thecorrected direction must be determined beforethe target is plotted on the firing chart. Thenorthing coordinates of the known point areused to determine the average northing. Thetarget grid is oriented by use of the correcteddirection. Then the shift is plotted in theusual manner.

(3) Observer procedures. Theobserver determines target location and OTdirection as he does for any mission. He is notrequired to superimpose an additional gridover his map. When the observer sends targetlocation, he must prefix his grid with theletter designator of the UTM grid zone inwhich he is located.

EXAMPLE:ADJUST FIRE, GRID PK 515478

e. Observer in the Primary Zone WithBattery in the Secondary Zone.

(1) Either zone may be designated asthe primary zone. The procedures areessentially the same in both cases. The firingbattery and the target or observer locationmust be plotted on a common grid when thefiring chart is constructed. The OT directionmust be corrected before the target grid isoriented for plotting subsequent corrections.

(2) Because the battery may have to fireinto either zone, when the observer's grid

zone is designated as primary, the followingalternatives exist:

(a) The firing battery must be plottedtwice on the firing chart. This requires doublenumbering.

(b) Two charts must be constructed.

(c) One chart covering both zonesmus t be constructed. This requiressuperimposing one grid over another.

13-46



FM 6-40


a. FADAC. FADAC Revision 5 Tapes,Matrix 2, contains a subroutine for grid and

observer-direction transformation.The

FADAC Revision 6 tape does not have thisroutine. If a unit is equipped with FADAC, itmust use graphic procedures.

b. Battery Computer System. TheSPRT;MAP entries define the coordinates,grid zone, and spheroid of the rectangle of thegeneral area in which operations are beingconducted. This rectangle is called the mapmodification (MAP MOD). It can be amaximum of 99,999 meters square. When theMAP MOD straddles meridian grid zones, the

grid zone lying in the southwesterncorner is

considered the base (standard) grid zone. TheMAP MOD boundaries should be specified byuse of base grid zone coordinates. The BCUconducts zone-to-zone transformation. Thefollowing guidelines must be followed whenentering target, observer, and othercoordinates:

(1) Within the MAP MOD and in thebase (standard) grid zone, short (five-digiteasting and five-digit northing) coordinatesmay be used, and the base grid zone isassumed.

(2) Withinthe MAP MOD and in grid

zones adjoining the base grid zone, shortcoordinates, expressed in the grid of theadjoining grid zone, may be used, but the gridzone must be specified. Short coordinates,expressed in the grid of the base grid zone,may be used and the base grid zone isassumed.

(3) Outside the MAP MOD and in thebase grid zone, long (six-digit easting andeight-digit northing) coordinates must beused, and the base zone is assumed.

(4) Outside the MAP MOD and in gridzones adjoining the base grid zone, longcoordinates must be used. They may beexpressed in the grid of the adjoining gridzone, and the grid zone must be specified; orthey may be expressed in the grid of the basegrid zone, and the base grid zone is assumed.

Section VIIHIGH-ANGLE FIRE

13-35. DESCRIPTIONa. Uses of High-Angle Fire. High-

angle fire is fire delivered at elevationsgreater than the elevation corresponding tothe maximum low-angle range for a charge.All howitzers are capable of deliveringhigh-angle fire effectively. High-angle fire isused for firing into or out of deep defilade suchas that found in heavily wooded,

mountainous, and urban areas. It may alsobe used to fire over high terrain features nearfriendly troops (fig 13-53). High-angle firemay be requested by the observer on the basisof the terrain in the target area. It may also beordered by the FDO on the basis of a terrainanalysis from the battery position to thetarget area. The primary characteristic ofhigh-angle fire is that an increase inelevation causes a decrease in range.

b. Limita t ions of High-AngleFire. Because high-angle fire involves Figure 13-53. High-angle fire.

13-47



FM 6-40

large quadrant elevations and long times offlight, it will not be as responsive aslow-angle fire in meeting the immediateneeds of a maneuver force. Trajectories arevulnerable to enemy detection. The long timeof flight makes it difficult for the observer toidentify his round. Time of flight may changedrastically from round to round. Time offlight must be computed for each roundduring the adjustment. To further aid theobserver, the FDC may announce time offlight in the message to observer.

13-36. HIGH-ANGLE GFTThe high-angle GFT (fig 13-54) consists of

one rule with ballistic data for multiplecharges on each side. The, scales

on thehigh-angle GFT, from top to bottom, are asfollows:

a. 1 00/R. The 100/R scale shows thenumber of mils necessary to move a burstleft/right or up/down 100 meters at the rangedetermined. The scale is read to the nearestmil.

b. Range. The range scale is expressedlogarithmically, in meters, and applies to allcharges appearing on one side. Rangeincreases from left to right and is read to thenearest 10 meters.

c. Elevation. Elevation is expressed inmils. It increases from right to left and is readto the nearest mil.

d. 10-Mi Site. The values on the10-mil site scale denote the site for each 10mils angle of site. The numbers are printed inred and are negative values. The scaleincreases from left to right and is visuallyinterpolated to the nearest tenth (0.1) of a mil.

e. Drift. The values on the drift scaleare in mils. The scale increases from right toleft for each charge and is visuallyinterpolated to the nearest mil.

f. Time of Flight. The time-of-flightscale is graduated in seconds and is used todetermine both time of flight (nearest wholesecond)

and VT fuze setting (drop the tenths).Note. Because the scales increase indifferent directions, care must be taken inreading the high-angle GFT. On thehigh-angle GFT, the 100/R, drift, an dtime-of-flight scales increase from right toleft. The range and JO-mil site scalesincrease from left to right. Figure 13-55shows an aid hat can be drawn on the cursorto help the computer read the scalescorrectly.

Figure 13-54. High-angle graphical firing table.

13-48



n 0 'R(FA'R63) 2300

ELEV

N126__ 4

3.70

S Sf

It

RG GOOD~~b0 30 0 6500 7

c, IFTso . 0 35 30 63 90 63 S0 ?5 70 63 60 53 30

-q T 40 9 .8 3 36 33 S7 56 33 54

IEQ"f

46 --

_ i' -EL E

v o -xI % , - O 2 0 23 S04 4 0 4 30 60 90--

'0 1jw~ FAC 2 25 0 3 40 45 50 60 ?O 9 100 '40

(,* TOF o

0 h

210 200

65 0035 so 45

Figure 13-55. Aid for reading high-angle scales.

13-37. DUTIES OFPERSONNEL

a. The fire direction officerdo the following:

must

(1) Include the command HIGHANGLE in the fire order.

(2) Consider high-angle fire character-istics in his selection of shell and fuze to firein the mission.

(a) Both APICM and DPICM can beused in high-angle fire for the same typetargets as in low-angle fire.

(b) The high-angle trajectory has twoinherent characteristics that affectmunitions selection-a steep angle of fall andlarge probable errors. The steep angle of fallmeans the projectile is almost vertical as itapproaches the ground. When th ehigh-explosive projectile bursts, the sidespray contains most of the fragmentation.Since in high-angle fire the projectile isnearly vertical, the side spray is in all

directions and nearly parallel to the ground(fig 13-56). Thus, shell HE, fuze Q and fuzeVT, are very effective when fired high angle.The large probable error in height of burst forM564, fuze time, makes the use of this fuzeimpractical in high-angle fire. Do not firefuze time M564 high angle.

Figure 13-56. High-angle versus low-angle-side spray.

13-49

"0 ON

FM 6-40

00O- 0 NA 17 A

40 35

46 45 " 43 42



FM 6-40

b. The VCO computes and announcesangle of site rather than site.

c. The computer will-(1) Select the charge to be fired.High-angle fire has two characteristics that

affect the selection of the charge-a shorterrange span for each charge and a rangeoverlap between charges. The range spanwithin which accurate fires can be deliveredby a particular charge is less for high-anglefire than for low-angle fire. This may cause aproblem during a high-angle fire mission,because a large observer correction maymove the round outside the capabilities of theinitial charge fired. This will necessitatechanging charges. Changing charges duringa high-angle fire mission is sometimesunavoidable, although it is not desirable. Forthis reason, the computer initially selects thecharge that is least likely to requirechanging. As a guideline, he selects thelowest charge that allows for a range shift ofat least 500 meters short of and 500 metersbeyond the initial chart range.

EXAMPLE:Using GFT 155-AM-2 as shown in figure13-54 and a chart range of 4,700 meters, thecomputer selects charge 3, because charge 2does not allowfor

a large observer correction.

(2) Include drift corrections. Drift isappreciably greater in high-angle fire thanin low-angle fire. Because drift changesgreatly for a relatively small elevationchange, a correction to compensate for drift isincluded in each deflection to be fired. Thecorrection is always applied to the left. Thecorrection is determined from the high-angleGFT and is added to the sum of the chartdeflection and the GFT deflection correction,

if available.(3) Include site corrections. If theFDO announces INCLUDING SITE, thecomputer applies site to elevation todetermine quadrant elevation to be fired.

(a) Site has a relatively small effectbecause of the large angle of fall inhigh-angle fire. Site is included when angleof site is greater than ±30 mils, when firing ahigh-angle registration, or when firing in amass mission. When several batteries are to

mass on a target and only one battery is toadjust, site should be computed at the initialrange for each battery. Site should berecomputed for the nonadjusting batterieswhen it is necessary to recompute site for theadjusting battery;

for example, if theadjusting battery changes charges. Siteshould also be recomputed for an individualnonadjusting battery if it changes charges.When adjustment is required before massingand when only one battery is to adjust,normally, the battery that is most centrallylocated should be designated as the adjustingbattery to minimize large differences in rangefor the nonadjusting batteries.

(b) If site is to be used, the FDOannounces INCLUDE SITE in the fireorder. Since one of the

criteria for includingsite is an angle of site greater than ±30 mils,the FDO may have to wait for the VCO tocompute and announce angle of site. In thissituation, the FDO issues a fire order andlater supplements it with the commandINCLUDE SITE.

(4) Announce high angle. AnnounceHIGH ANGLE as a special instructionwhen sending initial fire commands to theguns.

d. The RATELO may announce TIMEOF FLIGHT in the message to observer andwill announce SPLASH for each round.

13-38. HE.-HIGH-ANGLEMISSIONS

a. H i g h - A n g l e M i s s i o n C o m p u t e dWithout a GFT Set t ing .

(1) Upon receipt of the call for firereques t ing a high-angle method ofengagement, the FDO issues the fire order(fig 13-57).

(2) The computer announces the initialfire commands (fig 13-57).

(3) The RATELO announces th emessage to observer on the basis of the fireorder (fig 13-57).

(4) The chart operator determines chartdata.

(5) The VCO announces angle of sitegreater than t30 mils, and the FDO amends 4the fire order to include site.

13-50



FM 6-40

RECORD OF FIRE

CALLOR IRE WQ.T S4 A FS

Observer '-SWIGFE/STit t10011

Grid: /1

Polar:Oir Dis U/P VA 20/2

Shift : Dir , L . U/D

.W Si+ o l0nSiNOCorr

FiRE RDER SPE - - PtOf orr Si

INITIALIRE OMMANDS Mf' fn rR C41 h t c t 3 4 0 7 2 E

Ip Intr H Sh LotgTi GE

MTO -T63t -T ACf'8 2 7 (S) PER iF in Eff AnmnolhpTg LoainPriority Firing

Tt Location itSUBSEQUENT FIRECOMMANDSow Unit... .

Dir, MF Pa R oroR MF, Sh, FS .i Chart P. Corr Pf Chart NOR Si Eli pE yph, zr e IR, orr Chg F," Corr " Of )l Fired i RV Corr ( ) 1 t T

.,,.o~~o l ,, T e,,.,. ,....... , ,, .

OAORM 4 5 0 4 RE LACES DA fO0RM 504, M AY 76 , W H CH IS OBSOL TE THE PROPONENTUSTI AGENCY I'SEs RADoc0

I CT 78

Figure 13-57. High-angle fire order, initial fire commands, and message to observer.

(6) The computer determines and The computer determines the ele-

announces initial firing data (fig 13-58) by- vation to fire from the graphical firing

(a) Selecting the charge. The table.

computer places the MHL over the chart The computer determines site by -range and determines that the charge to fire Determining the 1-mu site factoris charge 4. (negative value) from the graphical

(b) Determining deflection. The firing table.

computer applies drift corresponding to Dividing the announced angle of siteelevation to determine deflection. by 10 and multiplying that quotient by

(c) Determining quadrant elevation, the 10-mil site factor.

RECORD OF FIRE

Oee.2CALL FOR IRE -&-T LA, A FS

Observer6-asJ ej)FE/IS/S Tgt . 3I0/R nGBi: _Si 3cr,'i V 4:2tO /R

Poler:Dir Dis U/ P ,_VA|V 1 0_/V 20/R

Shift : Dir - L1A U/P ,.3 7

ffl f .l ., i olka rT ...... ... Si . -+ 3.-' 1 Om Si -3,c, NORCorr

FiRE RDER seE C.woC E TE oCorr L49 Si - IINTALUIREMM A~~KtVAow:#sil i~i i~~i f;; Rg. 4QO Cht 3402 El, ,,f

SplInntr Sb Lot Chg F: Ti of34%G

SMTO (31 ' r, A E I t2 4i ('z+o)... PER IF 53 & rr .VT in i Amioip

Pgrcao it Firing SUBSEQUENT IRE COMMANDS

k .Car .... Chg, F: ..... Corr Df ( r ed _ Rg C r

Figure 13-58. High-angle initial firing data.

13-51



FM 6-40

The computer determines the quadrantelevation by algebraically adding siteto elevation.

(d) Announcing fire commands.

(7) The RATELO announces SHOTand SPLASH to the observer.

(8) Subsequent fire commands are

computed. Drift is determined and applied toevery deflection computed (fig 13-59).

(9) Whenhastyorspecial corrections arebeings used, the sign for high-anglequadrant correction is reversed.

RECORD OF FIRE

CALLOR IRE TGT 565/FSObserver a 1 2. &J.WE. iSS Tgt 5....ieY 355Grid: -7 3V V +70Polar:Dir Dis U/D VA 45' - 20/ftShi : Dir L/D+U//

sh" .owiJu AAo,U/D-4 Si+104 3.2 l.0 i ' 4 ,oOCerr

FRE ORDER SPEC. COR 14), , IlJC.LUOE SITE OfCorr Si

. . . . . . . . . . . . . . .

Tgt Locution Priority Firmn

... . . . . . . . . . . . .114TIA FRE OMMND C___nt UBEUETFIEEOMAD

Dir, MF Dev8tg NOB MF, Sb FS T Chort Df (err Df (hort NOB l G tp Tp

Sp nst, HA, artLotg $FhzTT QTp

Sh, : Dev mg Corr Cbg, : Corr Dt ( ) Fired Rg Corr (-If) El of l ip Type

.. .. . . . . . . . . ,. . , . . .., .:. . : ..

It 0. .. -•.0L .:$......L:;:3OiT 14: 0 lf:30 L

. . .. . . . : . . . . : ...: : : : : . , ..

61S90 L3o +SO F E )*jft80 -Iu'(.mXsin'

..... ....

....... .. ... .. .. ... .

1,12.2. y4VT'24 I W 3 z , ,3 I i L r

__ _-r -oee ----~,.----. -x - /1 , V -r_

,e_/1/4~-~fi- tuPAM ME79 Liz/)sQoCA----------- _

Figure 13-59. Subsequent high-angle adjustments.

13-52

POSITION 1IO/R POSITION PLATOON MUZZLE MUZZLE POSITION TOTAL POSITION CORRECTED TIME OLATERAL I GRAPHICAL DEFLECTION COMPARATIVE EIOCITY VELOCITY RANGE RANGE QUADRANT RANGE FIRE

G CORRECTION FIRING CORRECTION VELOCITY UNIT RANGE CORRECTION CORRECTION ELEVATION iSEP U ILEFT/RIGHTI TABLE (LEFT/RIGHT) ERROR CORRECTION CORRECTION (FORWARD I 1 1 CORRECTIONL N ( NCREASE/ FACTOR , (BACK - 1&[ COLUN 510 METERSTA N(D DECREASEI ITABLE , - INITIALS U 10 APPROPRIATE T) TABLE R RANGE I0 MUDER0AD *APPROPRIATE FT)

0 M DECREASE'-__IN 0 INCREASE-

R a b r d e[ fh i k

5 METERS 1 MIL T MIL 01 METER 01 METER I METER 5 METERS 1 ETERI MIL 10 ETERSPER ECOND

Z ' ,-'o / 5 .? I.Q -27.0 -27.0 -2 3S-262 - z _, .

q- - 0 ' R% + 01 _

R .0 . .. .. Po._,6OR150 4757 RtP4IR32.6 T O261t2LETE,

REVESE F DAFOR75 SE 84EDITION OF OCTORER R978SORSOLETE

HII



FM 6-40

b. High-Angle Registration. If thebattery position is in defilade or if most of thetargets are in defilade and the tacticalsituation will allow it, a high-angleregistration may be conducted. Only theimpact portion of a precision registration oran MPI registration can be conducted withhigh-angle fire because of the large PEHBwith the time fuze (M564).

(1) True adjusted elevation. Theadjusted elevation, determined from ahigh-angle impact registration, oftenincludes a false site. This false site is causedby the relationship of the comp site to totalsite. Comp site is a function of elevation. Inlow-angle fire, small changes in elevationcause small changes in comp site. On the

other hand, in high-angle fire, small changesin elevation cause large changes in comp site.In a high-angle registration, the comp sitedetermined at the initial elevation andapplied throughout the mission often differssubstant ia l ly from the ctomp sitecorresponding to the adjusted elevation. Thisfalse comp site, when added to the angle ofsite, produces a false site. To provide accuratedata, the FDC must determine the true siteand subtract it from the adjusted QE tocompute the true adjusted elevation. Todetermine the true site, successiveapproximation is used. The procedures forsuccessive approximation are as follows:

(a) At the conclusion of a registration,the computer subtracts the site fired from theadjusted QE to determine the first apparentelevation.

EXAMPLE:Adj QE 1062Si fired--5)

First app el 1067(1062 - (-5)= 1067)

(I) The computer then determines anew site by multiplying the angle of sitedivided by 10 by the lO-mil site factorcorresponding to the first apparent elevation.This yields a new site called the first apparentsite. If the first apparent site agrees within 1mil of the site fired, the first apparent site isthe true site.

EXAMPLE:Angle of si - 10 = +1.5lOmsi factor = -4.6First app si = - 6 . 9 , a - 7

(c) If the first apparent site is notwithin 1 mil of the site fired, the computer willcontinue the same process to determine asecond apparent elevation. To compute asecond apparent site, he will use the 10-milsite factor corresponding to the secondapparent elevation and the angle of site. Ifthe second apparent site is within 1 mil of thepreviously computed site, the secondapparent site is the true site.

EXAMPLE:

Adj QE- 1st app si = 2d app el1062 - (-7) = 106910$p si factor,-S el 1069 = -4.52d app s i -4 .5 x +1.5 = -6.75 Z -7

(d) If the second apparent site is notwithin 1 mil of the previously computed site,the computer will continue the process untilthe last computed site is within 1 mil of thepreviously computed site. The last sitecomputed is the true site.

(e) To compute the true adjustedelevation, the computer will subtract the truesite from the adjusted QE.

EXAMPLE:

The second apparent site is within 1 mil ofpreviously computed site. This is true site(-7).

Ad] QETrue siTrue adj el

1062- (-7)

1069

(2) High-angle GFT setting.

(a) The GFT settings for high-anglefire are written in the same manner as thosefor low-angle fire.

13-53



(b) The high-angle GFT setting isconstructed on the GFT by placing the MHLover the adjusted elevation for the charge anddrawing a range gage line through the GFTsetting range on the range scale (fig 13-60).

The MHL becomes the elevation gage line,and all data except range and 100/R are readunder the manufacturer's hairline. The GFTdeflection correction and charge are recordedon the cursor.

MHLEL 1069 RG 6740

6 00 65W00O00

I I I k 1 1 1 71240 1230 1220 1210 400O1110

12 .3 14 Is2

76 70 66 60 96

s, eb

0 1050 idoo' 1 9T . . . . I .. ... .Ii

i7 17-

3 4 4 6 7 6 9 1 0 11

F fl t I T[ 1 I i I 11 T I ~

50 45 40 35

52 CI 49 44

Figure 13-60. High-angle GFT setting.

(3) H i g h - a n g l e r eg i s t r a t i ontransfer limits. The registration correctionfor a registered charge will transfer to allranges and charges in that powder model.

c. High-Angle Mission ComputedWith a GFT Setting. A high-anglemission computed with a GFT setting appliedis computed as described in paragraph13-37a, except that data are read under theelevation gage line (MHL) (fig 13-61).

FM 6-40

13-54



RECORD OF FIRE

CALL OR IRE

Observer - 3' N:2. 4. AF/6SE /S Tgt

Grid: _ 43g vIpoIar:Dir Dis U/D VA____]V

Shift Dir L/R /U/.1

Fl ORDER P COf i HA A-A

INITIALIREOMMANDS

iTO G(5)" -rrA 07929 T --- I ER _-

To oato riority----- ngSUBSEQUENTIRE OMMANDS

C A P 'Chert ,Of Corr D h

DirMFoe U 1. FS Ti f F.red

GFT A CHG '1 LOT Y 2G.7qO EL1e69GFT )F C2OR LI I

POSITION 100 RLATERAL I GRAPHICALCORRECTION FIRINGCLEFT IGHT) TABLEI

POSITION PLATOON MUZZLEDEFLECTION COMPARATIVE VELOCITY

CORRECTION VELOCITY UNIT

LEFT RIGHTI ERROR CORRECTION(INCREASE FACTOR

OD DECREASE) ITABLEFPAPPROPRIATEDECREASE,INCREASE

d

01METER 0 1IMETER

Figure 13-61. High-angle mission computed with a GFT setting.

13-55

FM 6-40

P

00

MUZZLEVELOCITYRANGECORRECTION

0 -0(

POSITIONRANGECORRECTION(FORWARDRBACK1

TOTALRANGECORRECTION

0 0(POSITIONOUAORANT

ELEVATIONCORRECTIONI COLUMN N

TABLE F.

APPROPRIATE TI

1 MIL



FM 6-40

13-39o DPCM HfGH-ff-ANGLEREGSTIATwN

a. A registration with DPICM (M483A1)is conducted in the self-registration mode.

b. If the terrainin the target and/orbattery area indicates that high-angle fire

must be used, a high-angle high-burstregistration can be conducted by use of theM577 fuze. (It has a small height-of-burstprobable error.) This type of registration isconducted with the DPICM projectile in the

self-registration mode. The procedures arethe same as those for a low-angle high-burstregistration with the following exceptions:

(1) A minimum of 4 PEHB (TFT, tableG [fig 13-62]) or 50 meters, whichever isgreater, is added to the orienting pointground altitude.

(2) In a high-burst high-angleregistration, the fuze setting to fire is the fuzesetting corresponding to elevation plus compsite. Comp site in high-angle fire will be a

TABLE G

SUPPLEMENTARY DATA

2 3

ELEV

R

MIL M

0 0.0 4

1iLl5°6PROBABLE ERRORS

FUZE M564

D HB TB RB

M M SEC M

0

8

ANGLEOF

FALL

MIL

0265383

113

FT 155-AM-2

PROJ, HE, M107FUZE, PD, M557

9 10 11

COT TML MOANGLE VEL

OFFALL

M/S

316

308-301296290

M

0

3133054

12 13

COMP SITEFOR

ANGLE OF SITE+1 MIL -1 MIL

SITE SITE

MIL MIL

0.000 0.000

0.001 0.0000.002 -0.0020.005 -0.0050.010 -0.0OLO

2500 136.2 9 2 3 0.08 22 146 6.9 285 87 0.017 -0.0163000 166.6 11 2 4 0.08 23 180 5.6 280 129 0.026 -0.0243500 198.4 12 2 5 0.09 25 217 4.6 276 181 0.038 -0.035000 231.7 14 3 7 0.09 26 256 3.9 272 244 0.054 -0.0494500 267.0 161 3 810.10 27 2971 3.3 268 319 0.075 -0.068

5000 304.5 18 4 1010-11 29 341 2.9 265 410 0,103 -0.093

5500 344.9 20 4 12 0.11 30 389 2.5 262 517 0.142 -0.1256000 389.0 23' 5 14 0.12 32 441 2.2 259 647 0,199 -0.1716500 438.3 25 5 171 0.13 33 500 1.9 257 804 0.287 -0.2387000 495.5 28 6 20 0.14 35 566 1.6 255 1002 0.445 0.3 4 7

7500 566.7 31 7 24 0.15 37 647 1.4 254 1269 0.831 -0.553

677.4

886.8

996.2

1066.31122.11169.81211.6

1248.5

1280.7

34

37

35

32302724

21

8 3210.17 39 768 1.1 255 1714

9 46 0.19 38 977

10 53 0.21 35 1078

10 57 0.21 32 11429 60 0.22 30 11939 63 0.22 27 12389 65 0.22 24 1279

8 67 0.23 21 1317

8 69 0.23 1 1355

0.7

0.6

0.50.40.40.3

0.3

0.2

260

263

265267268269

269

2597

3042 -1.849

3309 -1.4613508 -1.3013665 -1.2083793 -1.146

3897 -1.101

L39801 -1. 66

-1. 91

2.216

1.576

1.371.2,o1.1831.131

1.092

Figure 13-62. Table G.

S

13-56

CHARGE4G

1

RANGE

M

500100015002000

8000

8000

7500

7000650060005500

5000

4500IFigurI13-2.-Tale

I

39.419.112.3

9.01

25.451.778.9

107.0

1 0.06 182 0.07 192 0.07 21



FM 6-40

relatively large number. Comp site isdetermined by entering the TFT, table G,column 12 or 13 (fig 13-62), to the nearest 500meters in range listed and extracting thecomp site factor for a ±1 mil angle of site. Theangle of site is multiplied by the comp sitefactor. The result is comp site. The comp siteis applied to the elevation determined fromthe high-angle graphical firing table. Themanufacturer's hairline is moved over thevalue of elevation plus comp site and readfrom the time-of-flight scale to the nearest0.1 fuze setting increment.

Note. The difference between the fuzesetting and the time of flight does not vary

more than 0.1 increment on the graphical

firing table.

(3) Drift and elevation are determinedfrom the high-angle graphical firing table.

(4) Site is determined by use of the10-mil site factor corresponding to theadjusted elevation multiplied by the newangle of site determined.

c. The adjusted elevation for ahigh-angle high-burst registration isdetermined in the same manner as in alow-angle high-burst registration. However,the new angle of site is based on the altitudeof the mean burst location.

d. The adjusted time is determined in the,same manner as in a low-angle high-burst

registration. The adjusted time is used7 todetermine a total fuze correction, which isapplied to the fuze setting corresponding tothe adjusted elevation when firing with aGFT setting In solving a concurrent-met todetermine position constants, the total fuze

correction is used as a known correction.The

total fuze. correction is determined bysubtracting the time corresponding toelevation plus comp site from the time fired.


a. FADAC. The method used fordetermining firing data in high--anglemissions is the same as that used for

low-angle missions with the followingexceptions:

(1) The FADAC operator enables thehigh-angle function.

(2) The FADAC operator doesdesignate a charge.

b. BCS Procedures. The BCS will usea high-angle trajectory-

(1) When the BCU operator selects thehigh-angle function.

(2) When the BCS encounters a maskviolation. The BCS will automaticallyattempt a high-angle solution if anattempted low-angle solution encounters amask violation.

13-57





FM 6-40

c. As long as the ballistic variables ofweather, materiel, and,, ammunition remainrelatively constant, any previously firedtarget may be refired with the same firingdata. If the ballistic conditions do not remainconstant, inaccuracies will develop insubsequentfirings. The battery shouldconduct a registration as soon as possible toprovide a means of determining subsequentballistic changes and to increase the

accuracy of relative locations.d. The FDC should plot the targetslocated by fire on the firing chart to providean additional means of target location ifrequested by the observer or directed by thefire direction officer. The last pinhole.

marking a target located by fire will providesufficient accuracy and should be noted witha red tick mark anda target number. Inshifting from the red tick mark, do not includesite or deflection correction, because theywere accounted for in the final pin location.Include computation for site if an up or down

correction is given.

14-2. CONSTRUCTION OFAN EMERGENCYOBSERVED FIRINGCHART

The FDC constructs the emergencyobserved firing chart on any suitable flatsurface to convert observer corrections tofiring data. The following steps are used toconstruct the emergency observed firingchart.

a. R e p r e s e n t i n g the B a t t e r yLocation. Place the RDP in the middle ofthe surface chosen to represent theemergency firing chart. The vertex willrepresent the battery center. Place a pinthere.

b. Establishing the Azimuth of Firea n d Common Deflec t ion . Withoutmoving the RDP, establish the primarydeflection index by placing a pin opposite thegraduation on the arc of the RDP (fig 14-1).

Fiue 41 sabihn th prmrydflcio ndx

14-2



FM 6-40

c. Plotting the Range to the Center ofSector or Target Location. Withoutmoving the RDP, place a pin opposite therange to the center of sector or at the locationof the target as reported by the observer (fig14-2).

Figure 14-2. Pin location of initial round.

d. Establishing a Grid North Index.

(1) Center a target grid over the pinholeto the center of sector or the target location.

(2) Align the 0-3200 line of the targetgrid with the left edge of the arm of therange-deflection protractor. The arrow on thetarget grid should face away from the vertexof the RDP, since the left edge of the RDP ispointing along the azimuth of lay (fig 14-3).

(3) Place a pin opposite the graduation

on the target grid corresponding to theazimuth of lay (fig 14-3).

Note. Notice that this pin now representsgrid north index, since the 0-3200 line an d

the arrow on the target grid coincide with the

edge of the RDP, which represents the

azimuth of lay. In other missions, depending

on the azimuth of lay, the pin may have to be

moved to establish this index.

Figure 14-3. Centered target grid.

e. Orienting the Target Grid. Rotatethe target grid until the announced OTdirection is opposite the north index (fig14-4). Plot subsequent corrections in thesame manner as those on surveyed firingcharts.

ii i iI

Figure 14-4. Oriented target grid.

14-3



FM 6-40

f. Plotting the Refinement . Afterplotting the end of mission refinementcorrections from the observer, determine thefinal chart range and deflection.

g. Tick Marking the F i n a l P inLocation. The tick mark for the target isconstructed in the same manner as for anyother target located by firing (red). It is not apermanent location on the firing chart,because it only temporarily establishes therelative location of the target point. Firing anoccasional check round will enable the FDCto keep the relative location updated.

h. Establishing a Permanent BatteryLocation. At the pin representing thebattery, draw a tick mark and label it by useof standard procedures.

i. Constructing a Grid North Indexfor the Target. Since the observer maywish to shift from this new known point,establish a grid north index as follows:

(1) Recenter the target grid over thelocation of the target tick mark. Place theedge of the RDP against the pin. Align the0-3200 line of the target grid with the arrowend pointing away from the vertex along theedge of the range-deflection protractor.

(2) Determine the azimuth to the finalpin location by converting the final chartdeflection to an azimuth.

EXAMPLE:Initial df (3200) - final df (3238) = L38 dfchangeAz of lay (1700)- df change (L38) = 1662

Since this is the direction represented by theedge of the RDP, use the same procedure thatwas demonstrated earlier in this paragraph;that is, place a pin opposite the graduation onthe target grid corresponding to the azimuthto the target (1662).

Note. This pin now represents a grid northindex, since the 0-3200 line and arrow on thetarget grid coincide with the edge of the RDP,which represents the azimuth to the finalpinlocation.

j. Establishing Permanent Deflec-tion Indexes. At the deflection index pin,using normal plotting techniques, construct apermanent deflection index for the plottedbattery position.

Note. If it appears that the unit will beremaining in the same position for asustained period of time, transfer operationsto a surveyed firing chart s soon as possible.Get off the emergency chart as soon aspossible.

14-3. BATTERY OBSERVEDFIRING CHARTS

Battery observed firing charts areconstructed when time permits the unit to firea registration. Normal procedures andsequence in the construction of a batteryobserved firing chart are as follows:

a. Have an observer select a registrationpoint near the center of the battery's zone offire.

b. Arbitrarily assign this registrationpoint an assumed altitude and assumed gridcoordinates. Plot this location on the firingchart. For simplicity, assign the point a gridintersection;

for example, grid 20004000,altitude 400 meters.

c. Conduct a precision registration.Include fuze time if possible.

d. Determine the adjusted data.

e. From the adjusted data, determine thedirection (azimuth) and distance (range) fromthe registration point to the battery.

f. Polar plot the battery center from theregistration point.

14-4. DETERMINATION OFDIRECTION FOR POLARPLOTTING

a. At the completion of the registration,the firing battery measures the azimuth orthe orienting angle (if an orienting line hasbeen established).

b. When an orienting line has not beenestablished, the azimuth of fire is measured,after the registration. The battery center is

14-4



FM 6-40

polar plotted on the back azimuth of themeasured azimuth. Drift should besubtracted from this back azimuth before thebattery is plotted.

c. When an orienting line has been

established, the batterywill measure the

orienting angle after the registration. Theazimuth of fire is computed (azimuth of

orienting line minus the orienting angle

equals the azimuth of fire). The battery center

is polar plotted from the registration point asin paragraph b above.

14-5. DETERMINATION OFRANGE ANDALTITUDE-IMPACTREGISTRATION

a. When maps and survey data are not

available, the determination of accurate site

is impossible. Every effort must be made to

determine approximate site. If thedetermination of an approximate site is not

feasible, site is assumed to be 0.

b. The range for polar plotting the firingunit location center grid is the rangecorresponding to the adjusted elevation(adjusted QE minus the site and any

height-of-burst correction 20/R. Place themanufacturer's hairline of the GFT over theadjusted elevation, and read the range underthe hairline.

c. Estimate the VI between the batteryand the registration point if possible. Use the

estimated VI in determining site by

successive approximation. Determine thebattery altitude in the following manner:

(1) Determine the range correspondingto the adjusted quadrant.

(2) Use the determined range and theestimated VI to compute the first apparentsite.

(3) Apply the site to the adjusted QE todetermine an elevation.

(4) Determine the range corresponding

to the determined elevation.

(5) Use the range corresponding to the

determined elevation and the estimated VI to

compute the second apparent site.

(6) Continue successive approximationuntil the site agrees with or is within 1 mil of

the previously computed site. Use the last site

computed to determine the adjustedelevation. Use the adjusted elevation todetermine the polar plot range.

(7) Apply the VI to the assumed altitudeof the registration point to determine thealtitude of the battery.

14-6. DETERMINATION OFRANGE ANDALTITUDE-T]IMEREGISTRATION, SITEUNKNOWN

a. The major sources of errors in range in

an observed firing chart, impact registration,are the lack of an accurate site andnonstandard conditions. If the site is

unknown or incorrect, the derived adjusted

elevation is in error by the amount of error in

site. Determining the polar plot range from

false elevation produces a false range.However, the effect of site on fuze setting isless severe. Therefore, the adjusted time can

be used as a good indicator of the adjustedelevation and the polar plot range.

b. Derive a site by subtracting theelevation corresponding to the adjusted time

(minus any position fuze correction, if any)

from the adjusted quadrant elevation. Usingthe graphical site table, determine the VI bymultiplying the polar plot range by the

derived site. Determine range by placing the

MHL of the GFT over the adjusted time and

reading range from beneath the MHL on the

RG scale. Determine the altitude of the

battery by applying the VI to the assumed

altitude of the registrationpoint.

c. When an average fuze correction isknown, increase the accuracy of site andelevation by determining the adjuisted

elevation in the following manner:

(1) Subtract the average fuze correction

from the adjusted time.

(2) Read the adjusted elevation

corresponding to the corrected adjusted time.

14-5



FM 6-40

14-7. DETERIMNATEON OFSITE BY FERdING (XO'SHIGH BURST)

An approximate site approaching surveyaccuracy may be determined from a modifiedhigh-burst registration fired after a precisionregistration.

a. Fuze setting (time) for a given charge isa function of elevation plus comp site.Therefore, if the fuze setting is kept constantand the QE varies, the elevation plus compsite to each of the resulting points of burst isconstant.

b. After a registration, fire a group ofrounds with the adjusted time but with a QElarge enough to raise the point of burst. Theraised point of burst should be visible fromthe battery location; therefore, the angle ofsite can be measured. Subtract the measuredangle of site to the burst from the quadrantelevation. The result is the elevation pluscomp site to the burst (QE = el + CAS +angle ofsite). The elevation plus comp sitecorresponds to the fuze setting fired (adjustedtime). It is equal to the elevation plus compsite to the registration point. Use the angle ofsite and the range corresponding to theadjusted elevation to determine the VI andsite to

the registration point.c. The procedure for conducting the XO's

high-burst is as follows:

(1) After the time portion of theregistration, the following command is sentto the f ir ing battery. OBSERVEHIGH-BURST REGISTRATION,MEASURE ANGLE OF SITE, 3ROUNDS, ADJUSTED DEFLECTION(so much), ADJUSTED TIME (so much),ADJUSTED QUADRANT ELEVATION(so much). The XO estimates the increase insite necessary to cause the bursts to be visiblefrom the battery position and adds it to thennounced quadrant elevation. He then hasthe registering piece fire three rounds at theadjusted time, the adjusted deflection, andthe increased quadrant elevation. The XOmeasures the angle of site to each burst withan aiming circle set up in the vicinity of theregistering piece. He then reports the averageobserved angle of site and the QE fired.

(2) The FDC determines the site to theregistration point, the adjusted elevation,and the VI between the battery and theregistration point as follows:

(a) Determine the elevation pluscomp site for the XO's high burst bysubtracting the average angle of site from theQE fired. The elevation plus comp sitedetermined is the elevation plus comp site tothe registration point.

(b) Determine the angle of site to theregistration point by subtracting theelevation plus comp site from the adjusted QEto the registration point.

(c) Using the C- and D-scales of theGST, determine the VI between the batteryand the registration point by multiplying theangle of site ((b) above) by the range to theregistration point in thousands of meters tothe nearest 10 meters.

(d) Using the appropriate site-rangescale of the GST, determine the site to theregistration point by dividing the VI by therange to the registration point. Do not movethe GST cursor from the position it was inwhen the VI was determined in (c) above.

(e) Derive the adjusted elevation bysubtracting the site ((d) above) from theadjusted quadrant elevation.

d. The "got minus asked for" ruleexplains the procedures for the XO's highburst (fig 14-5) in computing the angle of site.

ELEVATION 285 MILS(ACTUAL ELEVATIONPLUS COMP SITE)

GOT - ASKED FOR = +30 - (+20) = +10 MILSANGLE OF SITE

Figure 14-5. Executive officer's high burst.

14-6

S



FM 6-40

14-8. OFT SETTINGS

Construct the GFT setting by placing the

MHL over the chart range (polar plot range)and drawing the elevation gage line throughthe adjusted (derived) elevation and the time

gage line through the adjusted time.Construct the elevation and time gage lineseven though they-may be on th emanufacturer's hairline.

14-9. OBSERVED FIRINGCHART WITHINCOMPLETE SURVEY

A position area survey may be used in

conjunction with the observed firing chartuntil the surveyed firing chart is available.

The part of the chart establishedby firing

must be plotted to the same scale as that partobtained by survey.

14-10. CONSTRUCTION OFOBSERVED FIRINGCHART-POSITIONAREA SURVEY ONLY

The procedure for constructing a battalionobserved firing chart on the basis of theregistration of one battery having completed

a positionarea survey is as follows:

a. Establish a common orienting line(OL) for the battalion.

b. Starting at any point, run a traverse to

locate all battery positions horizontally and

vertically in relation to each other and toestablish common directional control for allorienting lines.

c. Plot the battery positions, altitudes,and orienting lines on tracing paper to thesame scale as that of the chart to be used. This

overlay, including the measured gridazimuth of the orienting lines, constitutes theposition area survey as known in the firedirection center.

d. Register one battery on the registrationpoint. From the adjusted data, start theobserved firing chart by plotting theregistered battery.

e. Derive the azimuth of fire from themeasured orienting angle of the registeringbattery. Use the derived azimuth of fire for

the direction of fire of the battery on theoverlay.

f. Orient the overlay so the battery center

of the registering battery is over the same

location on the chart. Rotate the overlay untilthe direction of fire lines on the chart and theoverlay coincide. Pinprick the locations of thenonregistering batteries, and then label themwith the proper altitudes in relation to theregistering battery.

g. Measure the azimuth from each

nonregistering battery to the registrationpoint. The azimuth of each battery'sorienting line minus the determined directionof fire equals the orienting angle for layingthe battery.

Secti'on II.

USE OF THE M1]0/M7 PLOTTIG BOARD

14-11. DETERINATEON OFMAP DATA

There may be situations when use of theemergency chart procedures discussed so farmay not be possible. In these cases, the XOmay have to compute firing data himself byusing the M10/M17 plotting board.

a. The observer transmits the call for fireto the fire direction center. He transmits

target locations by use of any of the accepted

methods of target location.However, the

request MARK CENTER OF SECTORshould be avoided unless maps ar e

unavailable.

b. Upon receipt of the call for fire, the XO

must determine the direction and range to the

target. He can do this by use of one of thefollowing methods:

(1) Given a MARK CENTER OF

SECTOR call for fire or no map, he can use

14-7



FM 6-40

his knowledge of the tactical situation toestimate an initial range and direction(azimuth) to the target.

(2) He can estimate the range anddirection to the target from a map, if

available.(3) He can measure the range and

direct ion from a map by using arange-deflection protractor.

14-12. CONVERSION OF MAPDATA INTO FIERECOMMANDS

Several steps are involved in theconversion of map data into initial firecommands when the M1O/M17 plottingboard must be used.

a. Determine the initial deflection to fireby comparing the azimuth to the initial targetlocation with the azimuth of lay. Then, usingthe LARS rule, apply the difference to thecommon deflection of 3200. In mark center ofsector missions and situations when the XOmust estimate initial azimuth to the target,the initial deflection fired will normally bethe deflection corresponding to the azimuth

of lay; for example, deflection 3200. This willnot be the case when the XO can measure amore accurate azimuth from his map.

b. Ignore site unless a large VI isndicated.

c. Determine elevation by using the rangeto the target obtained from the appropriatetabular firing table or graphical firing table.

d. Announce the initial fire commands inthe usual manner.

e. Compute angle T by comparing the OTdirection from the observer's call for fire andthe azimuth from the battery to the target (GTirection). Throughout the mission, retainthe angle T determined initially unless theweapons are shifted more than 200 mils fromthe deflection used to fire the initial round.

f. Determine 100/R at the initial rangeand record. It will be used in the computationof subsequent deflection shifts.

14-13. DETERMINATION OFDATA FORSUBSEQUENTROUNDS

a. Prepare the M10/M17 plotting boardfor observer's subsequent corrections byplacing a mark on the clearplastic disk at thenumber on the outer black scale thatcorresponds to the OT direction and anothermark opposite the GT direction. Label thesemarks 0 and G respectively so that byrotating the disk until one of the marks isopposite the head of the arrow (red zero) onthe base of the plotting board, you can obtaina graphical representation of eachsubsequent correction in relation to either theOT line or the GT line.

b. The observer follows normalprocedures during the adjustment. Thus, hissubsequent corrections can be plotted on theM10/M17 plotting board and converted intocorrections in relation to the GT line byremembering that the center of the plottingboard always represents the location of thelast burst.

(1) Using the procedures in b and cabove, select an appropriate scale; that is ,assign a convenient value to the squares on

the plotting board. Most shifts can be plottedwhen a value of 10 or 20 meters is assigned toeach small square. Use the 10-meters-per-square scale whenever possible, because it iseasier to use and is more accurate.

(2) Rotate the disk until the markrepresenting the OT direction is over the redarrow on the base. The plotting board is nowin OT position; that is, oriented in the OTdirection.

(3) Remembering that the center of theplotting board represents the impact of thelast round fired, plot the observer's correctionon the disk.

(4) Rotate the disk until the G mark isver the red arrow. The plotting board is nowin the GT position, or oriented along the GTdirection (GT line).

(5) Starting from the center of theplotting board, measure the observerscorrection in relation to the GT line as nowrepresented by the red index arrow on the

14-8



FM 6-40

base. Note that the observer's shift in relationto the OT line remains unchanged.

c. Firing data for subsequent rounds cannow be determined as follows:

(1) Deflection. Determinedeflection

to fire the next round in an adjust firemission. Convert the deviation correction (inmeters) in relation to the GT line to acorrection in mils. Apply the mil correction tothe previous deflection fired as follows:

(a) Multiply the value of 100/R for therange to the target by the meter deviation,and divide the product by 100.

EXAMPLE:

100/R xmeters deviation- deviation100

100/R can be determined by the followingformula:

100Initially determined range (in thousands)

(b) To produce the deflection to fire,apply the correction, in mils, to the lastdeflection sent to the guns.

(2) Elevation. Both the GFT and theTFT can be used to determine elevation asfollows:

(a) Using the GFT, first determine therange to fire the next round by adding/

SectionMAP-SPOT/SURVEYI

14-14. DETERMINATION OFSURVEYED LOCATIONAND AZIMUTH OF LAY

a. The surveyed location and azimuth oflay should be established as soon as possible.Surveyed locations are determined by thefollowing:

(1) Map spot. Map spot is fast, but itis less accurate.

5anal:tI

i

ubtracting the observer's range correctionlong the GT line to the last range ired. Thennove the MHL over the new range. If there isi current GFTP setting, read the elevation toire the next round under the elevation gageine. If there is no current GFT setting, read

he elevation to fire the next round underthe

nanufacturer's hairline.

(b) Using the TFT, apply thefollowing steps:

* Determine the C-factor (change inelevation for a 100-meter change inrange) at the initial chart range bysubtracting the elevation correspondingto the initial chart range from theelevation corresponding to a range 100meters greater than the initial range.

Express the amount to the nearest mil.This value is the C-factor that will beused throughout the mission.

* Compute the change in elevationrequired for the observer's rangecorrection along the GT line bymultiplying the C-factor by the changein range in hundreds.

C-factor x rangecorrection

100= change in elevation

Apply the change in elevation to the lastfired elevation. The result is the newelevation to fire.

III.

ED FIRING CHART

(2) Survey. Survey is more accurate,but it is slower.

b. If survey teams cannot provide thenecessary data immediately, a map-spotsurvey is conducted by the battery toestablish the battery center and azimuth oflay. To accomplish map-spot survey,associate terrain features with their locationson the map, and locate the battery center inrelation to the terrain features. Use hastysurvey methods.

14-9



FM 6-40

14-15. MAP-SPOTTECHNIQUE

a. Map-Spo t Survey. A map-spotsurvey is the application of basic map andterrain association. Be as accurate aspossible. The preferred technique forestablishing the battery center by map-spotsurvey is three-point resection. Themap-spotted location of the battery centerwill include eight-place grid coordinates andaltitude (in meters).

b. Directional Control. Directionalcontrol must also be provided; that is, anorienting station (OS) and the direction to theend of the orienting line (EOL). Commondirectional control should be established assoon as possible, preferably by simultaneous

observation or directional traverse during theday, or the Polaris-Kochab method at night.If none of these procedures can beaccomplished quickly, the battery must belaid magnetically. FM 6-50 contains a moredetailed discussion of the techniquesmentioned here.

14-16. CONSTRTUCTEON OF AMAP-SPOT SURVEYEDFIRING CHART(MANUAL)

a. The FDC must be provided three itemsof information to construct a map-spotsurveyed firing chart.

(1) Assumed grid coordinates of thebattery center.

(2) Assumed altitude of the battery.

(3) Assumed azimuth of lay.

b. When the above information isreceived, the FDC constructs the firing chart.

c. When met + VE techniques cannot beused, the battery will register by firing as thesituation permits.

d. A map-spot surveyed firing chart isonly as accurate as--

(1) The map-spotted location of thebattery center and the registration point.

(2) The azimuth of lay.

(3) The construction of the chart.

e. When using a map-spot surveyedfiring chart, the orienting angle must bemeasured and recorded after the battery islaid. This will facilitate determining theactual azimuth of lay when directionalcontrol is provided.

f. Replot any fired targets.

g. If the FDO suspects an error in eitherthe map-spotted location of the battery or theregistration point, or both, the GFT setting ismost likely incorrect if a registration hasbeen conducted. The GFT setting should bediscarded until better information isavailable.

14-17. TRANSFER FROMMAP-SPOT TOSURVEYEDFIRING CHART

a. When the position and target areasurveys are completed, the followinginformation is provided to the fire directioncenter:

(1) Battery center-coordinates andaltitude to the nearest 0.1 meter and azimuthto the EOL to the nearest 0.1 mil.

(2) Registration point-coordinates

and altitude to the nearest 0.1 meter.b. The surveyed f i r ing char t is

constructed to reflect the accurate locationsof the battery center and the registrationpoint and the actual azimuth of lay.

c. When the battery was initially laid, theorienting angle was measured and recorded.When the surveyed azimuth to the EOL isdetermined, the actual azimuth of lay must becomputed by use of the following formula:

Azimuth to EOL - orienting angle =

azimuth of layThe initial (map-spot) azimuth of lay may bein error. The actual azimuth on which thebattery was laid before survey was mostlikely not the azimuth obtained after thebattery was relaid on survey data.

d. When survey data are provided, theFDC must-

(1) Construct a surveyed firing chart.

(2) Recompute GFT settings.

14-10

S



11 ,IV -r

HASTY SPECIAL CORRECTION TABLES

M110A1/2 HASTYPOSITIONDEFLECTION HASTYPOSITIONDUADRANT HASTYMUZZLEVELOCITY

203-MM CORRECTIONSLATERALCORRECTION ELEVATIONCORRECTIONS CORRECTIONS(M/S)

(B-INCH) (L/R) (F/B)

FT R-U-1.5 1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

M106 (METERS) (METERS) .5 +1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0

RAGEI H G 201401 60 1801100112011401 16011801200 20 140 160 80 11001120140 11601800 200 - --____________

MILS MILS MILS

1 0 3GB 20140601801100 1201401 1601'1801200 1 2'3 4 6 8 9 7 8 9 1 0 12 +0 +0'+0'+0+0 + 1 + 1 + 1 + 1 +

- -1,,-1-- -11-2- - - 1-2-1-2 -2

1500 3GB 1 3 2 6 4 0 5 3 6 6 8 0 93 106 120133 6 7 89 1 0 1 2 + 0 + 0 + 0 + 1 + 1 + 1 + 2 + 2 + 2-1 -1 -1 -1 -2 -2 -2 ,-2-3

2000 4GBi861 2 0 3 1 4 04670680790 1 0 0 0 2 4 4 5 6 8 7 1 0 8 0 + 0 1 0 + 0 + 0 +1 +++1 +1-1 -1 -1 -1 -1-1 2 -2 -2 -2

2500 4GB 8 1 6 24 32 404856 6412780 12"3-4"6 7 8 9 10 12 + 0 + 0 + 0 + 1 + 1 + 1 + 1 + 2 + 2 +

-1 -11-1 -2 -21-2 -2 -3-3 -3

3000 4 G B 6 6 1 3 1 2 0 2 6 3 3 3 4 0 4 6 4 5 3 5 6 0 6 6 2 3 4 6 7 8 9 10 12 +0 +0 +0 +1 +1 +1 +2 +2 +2 +3-1 -1 -1 -2 -2 -2 -3 -3 -3 -4

3500 4GB 51117 22286344034551057 1 2 3 4 6 7 8 9 10 12+0+0+0+1 +1+1 +2 +2+3

S- - -1 - 1 -1 - -2-2 - 22

4000 46510 15520-251"30"35 40 45'501 TT3TW 7" 8910 - 1 2 + 0 + 0 +1 +1+1+2"+2"+2+33- -1 -2 -2 -2 -3 -3 -3 -4 -4

4500 4GB 4 8 1 8 1 3 1 7 2 2 " 2 6 " 3 13 5 4 44 3 4 6 7 8'9"10 2+0+0 +1 +1 +1 +2 +2+3

'+3

-11 _1-1 -2 - 2- 2 3 - 3 -4 5 -000 5GB 4i812 15120 24 28 32 364001234456 18+0+ +0 +1 +1 + 1 + 2 + 2 + 2 +

550 530-03V-21236134-18-2+23-3++-2

6000 5GB 36 7101316 22213263031 23 467 8 9 10 12 +0 +1+1 +2 +2 +3 +3 +4 4

-- -2- 23 0-3 4 - 5 - 5 -6

7000 5GB 2581114 17 202 2 252 2 3 4 6 7 8 9 1 0 1 2 + 0 + 1 1+2 +2 +3 +3+45

-0 -1 - -2 -2 -3 -3 -4 -5 -5

7500 5GB 3 6 9 1 5I18 2 2 261 2 34 6 78 910 12+0 +1+1+2+2+3+ .+4 +5

0L--1 -2 -2 -3 4 -4 -5 -5

8000 5B 2 57810111120 2 2512 3 46 7 8 9 1 0 1 2 + 0 +1+1 +2 ++3 ++4+5+6-1.-...2- 3..E.. .3.-

75000 5GB 11 8 10 1 16 L81 2 6 2 3 4 6 7 8 9 10 12 +0 +1 + 2 +2+3 + 4 +4 +9, +

-t- -2-2 -34 -4 - -7

- I -( i1m -m 1 - -

0

CD

a

-

0



I)

,, S

M110A1/2 HASTYPOSITIONDEFLECTION HASTYPOSITIONQUADRANT HASTY MUZZLEVELOCITY203-MM CORRECTIONSLATERALCORRECTION ELEVATiONCORRECTIONS ICORRECTIONS (IA/S)(8-INaCH) (L/R) (F/B)

FT R-Q-1 .-.- 1.0 -1.5 -2.0-2.5 -3.0 -3.5 -4.0 -4.5-5.0M106 (METERS) (METERS) fr.5+1.0 +1.5 +2.0 +2.5 +3.0 3.5 +4.0 +4.5 +5.0RANGE CHG 20 40 60 80 100 120 140 160 180 200 20_40 60 80 100 120 140 160 180 20 0

MILS MILS20 MILS8500 5GB 2 4 7911 14 1618212312 3 4 6 7 8 9.1 2 12 + 0 + 1 + 1 + 2 +3+3+4+4 +5+

-1 -2 -2 -3 -4- 4 -5 -5 -6

9000 5GB 2 4 6 8 11131511 2022 1 3 4 6 8 9 11 12 14 161+0 +1-+2 +3 +4 +5 + 6 + 6 +8+1- -2 -3 -4 -5 -6 -6 -7- -9-500 5GB 12 468710 1 2 1 4 1 6 182113 4 68 9 1 1 1 2 4 6 +0+1 +2 +3 +4+5+6 +7 +8+-1.-2 -23-34 -3-4 -4 -51-5 -

10000 5GB 2 4 6 8 10 12 14 16 18 20 1 7 T 6 8 9 11 12 14 16 +0 +1 +2 +3 +4 +5 +6 + +8-1 -2 -3 -4 5- 6 -7 -8 -9

10500 5GB 1 3 5 7 9 11 13 15 17 19 2 4 6 8 10 12 14 16 18 20 +1 +2 +3 +4 +6 +7 +8 +94+10.- 2 - 3 - 4 -5 -6 -8 -9 10-11 1

11000 7WB 13 517 91101214116180 1 2 3 44 5 6 7 . 8 1 + 0 + 0 + 1 + 1 + 2 +2+3+3+4+-1- -2-2 -3 -3 -4 -4 -5 -5

11500 7 W F 1 3 5 6 8 10 12 13 15 17 0 1 2 34 4 5 6 7 8 +0 +0 +1 +1 +2 +2 +3 +3 +4 +1 1-2-2 2-3 -3 -4 -4 -51-12000 7WB 1 356 8 910W1 13 15m1 1 2 3 4 6 7 8 9 10 12 +0++2+21+3+4 +5s + 5 + 6 +

-1-2-3-3 -4-5-61-6-7812500 7WB 1 34 6 8 9 11 12 14 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +2+3 +4 +5+5+6+7

:-1 -2 -3 3 -4 -5 -6 -6 -7 -813000 7WB 1 34 6 7 910 112134 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +3 +3 +4 +5+6+6+7

____-1-2 -3 -3.4 -5 -6 -6 -71-

1 3 5 0 0 7W YT1T2T 107ff 1 10T FT17 7 T +T0T + 1+2 +3+3 +4+5 +6+6 T

.........- ,-,I-1 -2 -3 -4 4 -5 -6 -7 -7 -84000 7WB 1 2 4 5 7 8 10 11 12 14 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +3 +3 +4 +5 +6 +6 +7II -1-2-3 4-4 -5 -6 -7-8

1 4 5 0 0 7 W 8 1 2 45 6 8 911 1213 12 3456 7 8 9 10 12 +0 +1 +2+3 +3+4 +5+6 +7+

I- 1-2 -3 -4 -4 -5 -6 - 7 3 -8 -15000 7W8 1 2 4 5 6 8 9 10 12 13 1 3 4 6 8 9 11 12 14 16 +1 +2 +3 +4 +5 +6 +7 +'8 +9+10

-2 -3 -4 -5 -6 -7 -8 -9 -10-111 5 5 0 0 7 W 8 1 2 3 5 6 7 9 10 11 12 1 3 4 6 r 9 11 12 14 16' +1 +2 +3 +4 +5 +6 +7 +8 +910

___-2-3 -4 -5 -6 -7 1-81 -9 101-1

=

0

0



aHASTYPOSITIONDEFLECTION

CORRECTIONSLATERALCORRECTION(L/R)

llCTEITRDC%

irHASTYPOSITIONOUADRANdTELEVATIONCORRECTIONS

(F/B)

(IMTFRS)

a -4., t,.

HASTYMUZZLEVELOCITYCORRECTIOiN(M/S)

-.5-1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0-.5 +1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0

aM11OA1/2203-MM(8-IMCH)FT R-Ql-1

nn ,11 o

'1

0

0

0

I1 U5G tE ,I IcibG _%_ I ...... I . IALw_ _-_-_---_------t

RANGE CHG ]2 40 60 80 100 120 140 160 180 200 0 40 60 80 100120 140 160 180 200

JMILS. - MILS MILS

16000 7WB 1 2 3 5 6 7 8 10 11 12 2 4 6 8 10 12 14 16 18 20 +1 +2 +4 +5 +7 +8 +9+11+12+14

1--- 3 - 5 -6 -7 -9-10-111-13-14

16500 8WB 1 2 3 4 6 7 8 9 10 12 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +3 +4 +4 +51+6+ +8- 1 -2--4 -5-51-6-71--9

17000 8WB 1 2 3 4 5 7 8 9 10 11 1 2 3 4 6 1 8 9 10 12 +0 +1 +2 +3 +4 +4 +5 +6 +7+-1 -2 -3 -4-5 -1-6-7 -8

17500 8WB 1 2 3 4 5 6 8 9810 11 1 2 3 4 6 7 8 9810 1 2 + 0 + 1 + 2 + 3 + 4 + 5 + 5 + 6 + +8- 1 - 2 - 3 - 4 - 5 - 6 - 6 - 7 -

18000 8WB 1 2 3 4 5 6 7 8 10 11 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +3 +4 +5 +6 +6 + +8-1 -2 -3 -4 -5 -6 -6 -71- -

18500 8WB 1 2 3 4 5 6 7 8 9 10 1- 3 4 6 8 811 . 12 14 16 +1 +2 +3 +4 +5 +6 +8 +9+1 +1-1 -2 -3 -4 -5 -6 -8 -9 -11-

19000 8WB 1 2 3 4 5 6 7 8 9 10 1 3 4 6 8 9 11 12 14 16 +1 +2 +3 +4 +5 +6 +8 +9+1 +11----- 2--3--4 -5 -6 -8 -924-1 3-1-2

19500 8WB 1 2 3 4 5 6 7 8 9 10 2 4 6 8 10 12 14 16 18 20 +1 +2 +4 +5 +7 +8+10+ +1 +141--23 -5 -6 -8 -9-11-12 -11

20000 8 1 2 3 4 5 6 7 8 9 10 1234 6 7 10 12112+0+1 + 2 + 3 4 + 5 + +1+ ++

--- 1 2-3-4-5 -6 -7-8--

205009 0 1 2 3 4 5 6 7 8 9 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +3 +4 + 5 + 6 + 7 + +8

-1- -2 -3 -4 -51-6-7 , -8 -1021000 9 0 1 2 3 4 5 6 7 8 9 1 2 3 4 6 7 8 9 10 12.+0 +1i+2 +3 +4 +5 +6 +7 + 9

it- -- 1 -2 -3 -41-5 -6 -7 - 8 - 1 0 9

21500 9 0 1 2 3 4 5 6 7 8 9 1 3 4 6 8 811 12 14 16 +1 +2 +3 +5 +6 +7 +8+10+11+-2 -3 -4 -6 -7 -8 -9 -1+12+1

22000 9 0 1 2 3 4 5 6 7 8 9 2 4 6 8 10 12 14 16 18 20 +1 +3 +4 +6 +8 +9+11+13+1 +16

-2 -4 -5 -7 -9 -101+12 +13 +1 +17



HASTYPOSITIOlIJDEFLECTIO HASTYPOSITIONUOUADRAPJT HASTYMUZZLEVELOCITYCORRECTIOIS LATERALCORRECTIOI ELEVATIOWCORRECTIOIS CORRECTIOJS (M/S)M 10OA2 (L/R) (F/B)FT B-S- 1.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

I650 (METERS) (METERS) 20+.5 +1.0 +1.5+2.0 +2.5 +3.0 +3.5 +4.0+4.5 +5.0RAN(3FICHG 20 j40 60 80 11001120j140 11601180120 [114 6 180 11001120 _40 =10L0S

2000 4GB 10 20 30 40 150 0 70 80 90 100 0 1 2 3 4 4 5 6 7 8 +0 + 0 + 0 + 0 + 0 + 0 + 0 + 1 + IJ -1 -1 -1 -1 1 -1 -1 -2 -2 -22500 4GB 8 16 24 32 40 48 56 64 72'80 1 2 3 4 6 7 8 9 1012 +0 +0 +0 +0 +1 +1 +1 +1 1+ 2

-1 -1 -1 -1 -2 -2 -2 -2 -3 -33000 4GB

6 1320

26 33'40 46 53 60 66 1 2 3 4 6 7 8 9 10 12 +0 +0 +0+0.+1 + 1 + 1 + 1 + 2 + 2-1 -1 -1 -2 -2 -2 -2 -3 -3 -3

3500 4GB 5 11 17 2228 34 40 45'51 57 1 2 3 4 6 7 8 9 0 120+0 0 +0 +1 +1 +1 +1 +2+2+-1 -1 -1 -2 -2 -2 -3 -3 -3 -3

4000 4GB 5 10 15 20 25 30 35 40 45 50 1 2 3 4 6 7 8 9 10 12 +0 0 +0+1+1 +1 +1+2+2+2

-1 -1 -1 -2 -2 -2 -3 -3 -3 -44500 4GB 4 8 1 3 17 22 26 31 35 40 44 1'2 3 4 6 7 8 9 10 12 + 0 + 0 + 0 + 1 +1 +2 +2+2 +3

1-1 -1 -2 -2 -2 -3 -3 -3 -3 -45000 4GB 4 8 12 16 20"24 28 32 36 40 1 2 3 4 6 7 8 9 10 12 +0 +0 + 1 +1 +2 +2 +2+3+3

. -1 -1 -2 -2 -2 -3 -3 -3 4 -45500 4GB 3 7 10 14 18 21 25 29 32 36 1 2 3 4 6 7 8 9 10 1 2 + 0 + 0 + 1 + 1 + 1 + 2 + 2 + 3 + 3 + 3

-1 -1 -2 -2 -2 -3 -3 -4 -4 -46000 5GB 3 6 10 113 16 20 23 26 30 33 1 2 3 4 6 7 8 9 1 2 +0 +1 +1 +2 +2 +3 +3 +4 +4

-1 -2 -2 -3 -3 -4 -4 -5 -6-66500 5GB 3 6 9 12 15 18 21 24 27 30 1 23 4 6 7 8 9 10 12 +0 +1 +1 +2 + 2 + 3 + 3 +4+5+5

-1 -2 -2 -3 -3 -4 -5 -5 -6 -67000 5GB 2 5 8 11 14 17 20 22 25 28 1 2 3 4 6 7 8 9 10 12 +0 +1 +1 +2 +2 +3 +4 +4 +5 +5

-1 -2 -2 -3 -3 -4 -5 -5 -6 -67500 5GB 2 5 8 10 13 16 18 21 24 26 1 2 3 4 6 7 8 9 10 12 +0 +1 +1 +2 +3 +3 +4 +4 +5 +6I -1 -1 -1 -2 -3 -3 -4 -4 -5 -6

8000 rw5 716 12 15 17 20 22 25 1 2 3 4 6 7 8 9 10 12 +0 + +1 +2 +3 +3 +4 +5 +5-1 -2 -2 -3 -4 -4 -5 -6 -6 -7

8500 5GB 2 4 7 9 11 14 16 18 21 23 1 2 3 4 6 7 8 9 10 12 +0'+1 +1 +2 +3 +3 + 4 + 5 + 5 + 6

-1 -2 -2 -3 -4 -4 -5 -6 -6 -79 5 G B 2W4 T 8 1H 13 5 92022 T 3 4 6 8 '9 U1 12 14 16 +0 +1i1+2+3 +4 +5+61+71+8+

J- A________ - -2 . -3 1-4 -5 -6 -7 -8 -9 -

44 1

=

&0



a A

HASTYPOSITIONDEFLECTION HASTYPOSITIONQUADRANT HASTY MUZZLEVELOCITYCORRECTIONS LATERALCORRECTION ELEVATIONJCORRECTIONS ICORRECTIONS (MI/S)

M11OA2 (L/R) (F/B)FT 8-S-1 -.5 1.

-1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

M650 (METERS(M_(ETERS)- +.5 1.0 1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0

RANGE CHG 20I40I6018j11001o20 40t I180Ioo01200 20 140J60 120140 1160118 I200j . I " MILS .MILS . .MILS

9500 5GB 2 4 6 8 10 12 14 16 18 21 1 3 4 6 8 9 11 12 14. 16 +0 +1 +2 +3 +4 +5 +6 +7 +8 +9I-1 1-2 1-31-4 -51-6 -71 -8 -9-1

10000 5GB 2 4 6 8 10 12 14 16 18 20 1 3 4 6 8 9 11 12 14 16 +0 +1 +2 +3+4 +5 +6 +7+8+9-1 -2 -3 -4 -5 -6-71-8-91010500 5GB 1 3 5 7 9 11 13 15 17 19 2 4 6 8 10 12 14 16 18 20 +1 +2 +3 +5 +6 +7 +8+10+11+12

-2-3 -4-5 -7 -8 -9-10-12-13

11000 6WB 1 3 5 7 9 10 12 14 16 18 1 2 3 4 6 7 8 9 10.12.+0 +1 +2 +3 +3 +4 +5 +61+7+7

a-1--- _In -4 -4 i-54-11500 6WB 1 3 5 6 8 10 12 13 15 17 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +3 +3 +4 +5+6+7+7

-1 -2 -3 -4 4 -5 -6 -7 -8 -812000 6WB 1 3 5 6 8 10 11 13 15 16 1 2 3 4 6 7 8 -9 10 12 +0 +1 +2 +3 +4 +4+5 +6+7+8

-1 -2 -3 -4 -5 -5 -6 -7 -8 -9

12500 6WB 1 3 4 6 8 9 11 12 14 16 1 3 4 6 8 9 11 12 14 16 +1 +2 +3 +4 +5 +6 +7 +8+10+11-2 -3 -4 -5 -6 -7 -8 -9-10 12

13000 6WB 1 3 4 6 7 9 10 12 13 15 1 3 4 6 8 9 11 12 14 16 +1 +2 +3 +4 +5 +6 +8 +9+10+11-2 -3 -4 -5 -6 -7 -8-10-11 -12

13500 6WB 1 2 4 5 7 8 10 11 13 14 2 4 6 8 10 12 14 16 18 20 +1 +2 +4 +5 +7 +8 10+11 +13+14

- - - - -- -2 -3 -5 -6 -8 -9 11 -12-1315

14000 8 1 2 4 5 7 8 10 11 12 14 0 1 2 3 4 4 5 6 7 8 +0 +1 +1 +2 +2 +3 +3 +4 +5 +5

1 -2 -2 -3 -3 -4 -4 -5 -5 -614500 8 1 2 4 5 6 8 9 11 12 13 0 1 2 3 4 4 5 6 7 8 +0 +1 +1 +2 +2 +3 +3 +4 +5 +5

-1 -2 -2 -3 -3 -4 -4 -5 -6 -6

15000 8 1 2 4 5 6 8 9110 12 13 0 1 2 3 4 4 5 6 7 8 +0 +1+1 +2 +2 +3 +4+4+55

-1 -2 -2 -3 -3 -4 -5 - 6 6

15500 8 1 2 3 5 6 7 9 10 11 12 0 1 2 3 4 4 5 6 7 8 +0 +1 +1 +2 +2 +3 +4 +4 +5 +5-1 -2 -2 -3 -3 -4 -5 -5 -6 6

16000 8 1 2 3 5 6 7 8 10 11 12 0 1 2 3 4 4 5 6 7 8 +0 +1 +1 +2 +3 +3 +4 +4 +5 +6-1 -2 -2 -3 -3 -4 -5 -5 6 -6

16500 8 1 234 6 7 8 9101 01 223 4 4 5 6 7 8 + 0 + 1 + 1 + 2 + 3 + 3 + 4 + 4 5 61 -2 -2 -31 4 -41 -51 5 -6 -

-

a -v I



HASTYPOSITIOWdDEFLECTIOPJ HASTYPOSITIOFJQUADRAIJT HASTYUZZLE VELOCITYCORRECTIOIJSLATERALCORRECTIOI ELEVATIORICORRECTIOIS ICORRECTIOPIS (M/S)

MI 10A2 (L/R) (F/B)FT 8-S-1 -.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

11550 (METERS) (METERS)+.5 +1.0 +1.5 +2.0 +2.5 +3.0 +3.5+4.0 +4.5 +5.0IRANGc o20140f0180 1100jo120F404o60 8i Ooo4 ,8 11 1 ,,o iOo o1200].

t _ _ =-=-=-MILS -=-=-=-=J=-=-=-=-MILS -------- -- =-= = MI 1 --

17000 8 1 2 3 4 5 7 8 9 10 11 0 1 2 3 4 4 5 6 7 8 +0 +1 +1 +2 +3'+3 +4 +4 5+6-1 -2 -2;-3 -4 -4 -5 -5 -7

17500 8 1 2 3 4 5 6 8 9 10 11 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +3 +4 +5 +6 +7 +8 +9-1 -2 -3 -4 -5 -6 -7 -8 -9-10

18000 8 1 2 3 4 5 6 7 8 10 11 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +3 +4 +5 +6 +7 +8 +9-1 -2 -3 -4 -5 J6-71 8 -9-1

18500 8 1 2 3 4 5 6 7 8 9 10 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +3 +4+5 +6+7 +8+9- -2 -2 -3 -4 -5 -6 -7 -8 -9-10

19000 8 1 2 3 o 4 5 6 7 8 9 1 0 1 2 3 4 6 7 8 9 10 12 +0 + 1 + 2 + 3 +4 +5 +6 7 +8+ 91 - -I - -0-1 -2 -3 -4 -5 -6 -7 -8 9

19500 8 1 2 3 4 5 6 7 8 9 10 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +3 +4 + 5 + 6 + 7 + 8 + 9-2 -2 -3 -4 -5 -6 -7 -8 -9-10

20000 8 1 2 3 4 5 6 7 8 9 10 1 3 4 6 8 9 11 12 14 16 +1 +2 +4 +5 +6 +8 +9+10+12+13-2 -3 -4 -6 -7 -8 -10-11-12-14

20500 8 0 1 2 3 4 5 6 7 8 9 1 3 4 6 8 9 11 12 14 16 +1 +2 +4 +5 +6 +8 +9+10+12+13-2 -3 -5 -6 -7 -9 10-11 -13 -14

2100 1 2 3 4 5 6 7 8 9 1 2 3 4 6 '7 8 9 10 12 +1 +2 +3 +4 +5 +6 +7 +8+9+10-2 -3 -4 -5 -6 -7 -8 -9 10-11

21500 9 0 1 2 3 4 5 6 7 8 9 1 2 3 4 6 7 8 9 10 12 +1 +2 +3 +4 +5 + 6 + 7 +8+9+10-2 -3 -4 -5 -6 -7 -8 -9 10-11

22000 9 801 2r3 4 5 6 7 8 9 1 2 3 4 6 7 8 9 10 12 +1+2 +3 +4+5 + 6 + 7 + 8 + + 1

S'I-2 -3 4 -5 -6 .7 -R 922500 9 0 1 2 3 4 5 6 7 8 8 1 3 4 6 8 9 11 12 14 16 +1 +2 +4 +5 +7 +8 10+11 +12+14

1 -1 -2 -4 -5 -7 -8 10-11 -12-1423000 9 0 1 2 3 4 5 6 6 7 8 1 3 4 6 8 9 11 12 14 16 +1 +2 +4 +5 +7 +8 +-0I11 +12+14

5-2 -3 -5 -6 -8 -9 -11-12 -14-1523500 9 0 1 2 3 4 5 5 6 7 8 2 4 6 8 10 12 14 16 18 20 +1 +3 +5 +7 +9+10 +12 +141+16+18

4 5 5-1 -3 -5 -7 -9 11 J12-14-16-1824000 8R 0 1 2 3 4 5 5 6 7 8 1 2 3 4 6 7 8 9 10 12 +1 +2 +3 +4 +6 +7 +8 +9+11+12

-2 -3 -4 -5 -7 -8 -9 10 -11 13-.... - -

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0HASTYPOSITIONDEFLECTION HASTYPOSITION QUADRANT HASTYMUZZLEVELOCITY

CORRECTIONSLATERALCORRECTION ELEVATIONCORRECTIONS CORRECTIONS(M/S)

M110A2 (L/R) (F/B)

FT e -iF-.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5-5.0

M650 (METERS) (METERS)1.5+1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0

RANGE CHG ]20o 1o60o1 80 100 112011401160 11802o0020 40160 80i100112011401160 11801200]

I___ JMILS _-MILS MILS=

24500 8R 0 1 2 3 4 4 5 6 7 8 1 3 4 6 8 9 11 12 14 16 +1 +3 +4 +6 +8 +9+11+13+11- 3 -4 -6 -8 -9-11-13-14-16

25000 8R 0 1 2 3 4 4 5 6 7 8 1 3 4 6 8 9 11 12 14 16 +1 +3 +5 +6 +8+10+11+13+15+16

-2 -4 -6 -7 -9 -11 -12-14-16-17

25500 8R 0 1 213 3 4 5 6 7 7 2 4 6 8 10 12 14 1 6 18 20 +2 +4 +6 +8+10 +12 +14 +16 +19+21

- -- 3 -5 -7 -9-11 -131-15 -17 -2 -22

26000 9R 0 1 213 3 4 5 6 6 7 0 1 2 3 4 4 5 6 7 8 +0 +1 +2 +3 + +5 +6 +7+ +8-1 -2 -3 -4 -5 -6 -6 -7 -8 -9

26500 9R 0'1 2 3 3 4 5 6 6 7 1 2 3 4 6 7 8 9 10 12+1+2 + +5+0T8+9+10+12+13-2 -3 - -6 -7:-8 -10-11 -12-14

27000 9R 0 1 2 2 3 4 5 5 6 7 1 2 3 4 6 7 8 9 10 12 +1 +2 +4 +5 +7 +8 +9+11 +12+14

-2 -3 -5 -6 -7 -9 101-11 -1 -14

27500 9R 0 1 2 2 3 4 5 5 6 7 1 2 3 4 6 7 8 9 10 12 +1 +2 + +5 +7 +8+10+11 +1 4-2 -3 -5 -6 -8 -9 10-12-1 -14

28000 9R 0 1 2 2 3 4 5 5 6 7 1 2 3 4 6 7 8 9 10 12 +1 +3 + +6 +7 +9+11 +12+14+15-2 -3 -5 -6 -8 -91-11 -12 -14 -15

28500 9R 0 1 2 2 3 4 4 5 6 7 1 3 4 6 8 9 11 12 14 16 +2 +4 +6 +9+11 +13 +16 +18+20 +23-3 -5 -7 -9-11 -13 -15 -171-19-21

S29000 R 0 1 2 2 3 4 4 5 6 62 4 6 8 10 12 14 16 1 +3 +6 +915+18+21+ 4+2+307 3 6 -9 12 1 -171-20 -23 -2 8

0

0

0



HASTYPOSITIONDEFLECTION HASTYPOSITIONQUADRANT HASTYMUZZLEVELOCITYM109A2/3 CORRECTIONSLATERALCORRECTION ELEVATIONCORRECTIONS CORRECTIONS(M/S)

M198 (L/R) (F/8)155-AN-1 -.5-1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

483A1 (METERS) (METERS) +.5+1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5+5.0

RANGE G 20 140 160 180 1100 1120 1140 1160 11801200120 140 160 1801100 _110114011601180 1200)MILS MiLS MILS

1000 4GB 20406080100120140116018 0 2 0 1234 6 7 8 . 9 1 0 12+0 +0 + 0 + 0 + 0 + 1 1 1+1,-1 -1 -1 -1 -1 -2 -2 -2-2

1500 4GB 13 26 40"53"66"80 93 106 120 133 1 2 3 4 6 7 8 9 10 12'+0 +0 +0 +0 +0 +1+1 +1+1+1-1 -1

-1 2 -2 -2 2 -3 -3 -32000 F4B 0 20 30 40 50 60 70 80 90 100 1 2 3 4 6 7 8 9 10 12 +0 +0 +1 +1 +1 +2 +2 +2 +3 +31--1 -1-2--2 -2-2-3.-3 -3-3

2500 4GB 8 16 24 32 40 48 56 64 72 80 1 2 3 4 6 7 8 9 10 12 +0 +0 +1 +1 +2 +2 + 3 + 3 + 4 + 4

.. -1 -2 -2 -2-3-3-3-4-4-43000 5GB 6 13 20 26 33 40 46 53 60 66 1 2 3 4 6 7 8 9 10 12 +0 +0 +1 +1 +1 +2 + 2 + 2 + 3 + 3

No , -1-1-22-2-3-33-3-4

3500 5GB 5 11 1712- 28134 40145 51 57 1 2 3 4 6 7 8 9 10 12 + 0 + 0 + 1 + 1 + 1 + 2 + 2 + 3 + 3 + 3-.-. , - - 1 - 1 - 2 -2 -2 - 33 -3-4-4

4000 5GB 5110-15120 25130 35 40 45 50 1 2 3 4 6 7 8 9 10 12 +0 +0 +1 +1 +2 +2 +2+3+3+3

-1 -1 -2 -2 -3 -3 -3 -4- -44500 5GB 4 8 13 17 22 26 31 35 40 44 1 2 3 4 6 7 8 9 10 12 +0 +0 +1 +1 +2+2 +3 +3+4+4- .. - I I - --- 1 -1 -21-2 -31-3.-3-4-4-5

5000 5GB 4 8 12 16 20 24 28 32 36 40 1 2 3 4 6 7 8 9 10112 +0 +0 +1 +1 +2 +2+3 +3+4+4-1 -1 -2 -2 -3 -3 -4 -4 -5 -5

5500 5GB 3 7 10114 18 21 25 29 32 36 1 2 3 4 6 7 8 9 1 0 12 +0 +1 +1 +2 +2 +3 +3.+4+4+5

-1 -2 -2 -2 -3 -3 -4 -4 5 -56000 5GB 3 6 10 13 16 20 23 26 30 33 1 3 4 6 8 9 11 12 14 16 +0 +1 +2 +3 +3 +4 + 5 + 6 + 6 + 7

-1 -2 -3 -3 -4 -5 -5 -6 -7 -86500 5GB 3 6 9112 15 18 21 24 27 30 1 3 4 6 8 9 11 12 1416 +0 +1 +2 +3.+4 +4 +5 +6+7+8

-1 -2 -3 -4 -4 -5 -6 -6 -7 -8

7000 5GB 2 5 8 11 14 17 20 22 25 28 1 3 4 6 8 9 11 12 14 16 +0 +1 +2 +3 +4 +5 +6 +6 +7 +8-1 -2 -3 -4 -4 -5 -6 7 -8 -8

7500 7WB 2 5 8110 13 16518 21 24 26 0 1 2 3 4 4 5 6 7 8 +0 +0 +1+1 +1 +2 + 2 + 3 + 3 + 3... .. -1 1-21-2 -2 -3 - 3 -4 -4 -4

8000 7WB 25 719_12 15 17 20 22125 0 1 2 3 4 4 5 6 71 8+01+0 +1 +1 2+2+2+2 +3 +3+4. .. I I -1 -1 -2 -2 -2 -3 -3 -4 -4 -4

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0HASTY POSITIONDEFLECTION HASTYPOSITIONQUADRANT HASTYMUZZLEVELOCITY

M109A2/3 CORRECTIONSLATERALCORRECTION ELEVATIONCORRECTIONS CORRECTIONS(M/S)

M198 (L/R) (F/B)

155-AN-1 -. 1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

483A1 (METERS) (METERS)j+.5 +1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0

RANGEiCHG120140 160 a80100 120 1140 160 1801 20020140 16 as 10011201140 116011801200..

J.. . --- MILS -------- -------- MILS -------- j-MILS8500 7WB 2 4 7 9 11 14 16 18 21 23 0 1 213 4 4 5 6 7 8 "+00 +1 +1 4 +2 +2 +3+34

-1 -1 -2 -2 -3 -3 -3 -4 -4 -

9000 7WB 2 4 6 8 11 13 15 17 20 22 0 1 2 3 4 4 5 6 7 8 +0 +0 +1 +1 +2.+2 + 2 + 3 + 3 + 4

-1 -1 -2 -2 -3 -3 -3 -4 -4 -5

9500 7WB 2 4 6 8 10112 14 16 18 21 1 2 3 4 6 7 8 9 10 12 +0a+1 +1 +2 +3 +3 + 4 + 5 + 5 61 -2 -2 -3 -4 -4 -5 -6 -6 -7

10000 7WB 2 4 6 8 10 12 14 16 18 20 1 2 3 4 6 7 8 9 10 12 +0 +1 +1 +2 +3 +4+4 +5+6+6

-1 -2 -2 -3 -4 -4 -5 -6 -6 -7

10500 7WB 1 3 5 7 9 11 13 15 17 19 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +2 +3+4 +4 +5+6+6

-1 -2 -3 -3 -4 -5 -5 -6 -7 -1

11000 7WB 1 3 5 7 9 10 12 14 16 18 1 2 3 4 6 7 8 9 10 12 +0 +1I+2 +2 +3 +4 + 4 + 5 + 6 + 6-1 -2 -3 -3 -4 -5 -5 -6 -7 -7

11500 7WB 1 3 5 6 8 10112 13 15 17 1 2 3 4 6 7 8 9 10 12+1i+1 +2 +31+4 +4 +5+6+6+1

I I -1 -1 -2 -3 -4 -4 -5 -6 -6 -7

12000 7WB 1 3 5 6 8 10 11 13 15 16 1 3 4 6 8 9 11 12 14 16 +0 +1 +2 +3 +4 +5 +6 +7 +8 +9-1 -2 -3 -4 -5 -6 -7 -8 -9-10

12500 7WB 11 3 4 6 8 9 11, 12 14 16 1 3 4 6 8 9 11 12 14_ 16 +0 +2 +2 +41 4 +6 +6 +8 +8+10

-2 -2 -3 -4 -5 -6 -7 -8 -9-10

13000 7WB 1 3 4 6 7 9 10 12 13 15 2 4 6 8 10 12 14 16 18 20 +1 +2 +3 +5 +6 +7 +9+10.11+12I I-2 -3 -4 -6 -7 -8 -9 -11 12-13

13500 7WB 1 2 4 5 7 8 10 11 13 14 2 517 10 12 14 71 19 22 24 +1 +3 +4 +6 +7 +9 11+12 +14+1511-2 -4 -5 -7 -8 10 -11 -13 15-16

14000 7WB 1 2 4 5 7 8 10 11 12 14 4 7 11 14 18 22 25 29 32 36 +2 +5 +7 10 +12 15 +17+20 +22+25

1 ,,-2 -5 -7 10 -12 14-17 -19 -21 -2614500 BWB T 2 4 5 6 8 9 11 12131 2 3 4 6 7 8 9 10 12 +0 +1 +2 +3 +3 +4 +5+6+6+7-1 -2 -3 -3 -4 -5 -6 -6 -7 -8

15000 8WB 1 2 4 5 6 8 9 10 12 13 1 3 4 6 8 9 11 12 14 16 +0 +2 +3 +4 +5 +6 +7 +8 +9+10

I Ia 1-2 -3 -4 -5 -6 -7 -8 -9 10-11

15500 8WB 1 2 3 5 6 7 9 10 11 12 1 3 4 6 8 9 11 12 14 16 +1 +2 +3 +4 +5 +6 +7 +8 +9+10

-2 -3 -4 -5 -6 -7 -8 -9 1-101

16000 8WB 1 2 3 5 6 7 8 10 11 12 1 3 4 6 8 9 11 12 14 16 +1 +2 +3 +4 +5 +6 +7 +8 +9+10

I 1650-2 -3 -4 -5 -6 -71 8 -9 10-11

8WB 1 2 3 4 6 7 8 9 10 12 2 4 6 8 10 12 14 16 18 20 +1 +2 +4 +5 +6 +8 +9+11 2+13-2 -3 -5 -6 -7 -9-10-11 3-14

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HASTYPOSITIONDEFLECTION HASTYPOSITIONQUADRANT HASTYMUZZLEVELOCITYM109A2/3 CORRECTIONS LATERAL CORRECTION ELEVATION CORRECTIONS CORRECTIONS (M/S)

M198 (L/R) (F/B)155-AN-1 -. 1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

483A1 (METERS) (METERS)-.5 +1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0HAoIHGI20 40 {60 180 1100 120 11401160 1 8oI2j20 40160 1801 112 114 02o 200

'1 MILS MILS MILS17000 8WB 1 2 3 4 5 7 8 9 1 11 3 6 10 3 1 1 2 6 2 2+ +5 +7 +9 12 +141+16 +14+20+2

jzj 4 -4 -7 -9 11 13-15-1 -20-22

HASTYPOSITIONDEFLECTION HASTYMUZZLE VELOCITYM109A2/3 CORRECTIONSLATERALCORRECTION HASTYPOSITIONQUADRANT

CORRECTIONS(M/S)M198 (L/R) ELEVATION CORRECTIONS155-AM-2 -.5 1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

M107 (METERS) ( ETERS) +.5 +1.0 +1.5 +2.0+2.5 +3.0 +3.5 +4.0 +4.5 +5.0RANGE CHG 20....60-080 -MS1,101140 -118000--04 0 0102040 160 180 2001MILS __2

1000 4GB 204060801001209140160 180200 1 2 3 4 6 7 8 9 10 12 +0 +0 +1+1 +1+1 +1+1+2+211 7i-0 -0 -0 -1 -1 -1 11 -1 - 21500 4GB 1 3 2 6 4 0 5 3 6 '8 0 9 3 106f120 31 2 3 4 6 7 8 -9 Wi0 2 + + 0 + 1 J+j+ 2+ 2

-1 -1 -1 1 -2 -2 -2 -2 -2 -32000 4GB 10 20 30 40 50 60 70 80 90 100 1 2 3 4 6 7 8 9 10 121+0+0+1 1 +1 +2 +2 +3 +3

_1 -2 -2 -2 -2 -3 -3 -32500 4 G B 816 24 32 40 48 56 64 72 80 1 2 3 4 6 7 8 9 10 12 +0 +0 +1 +1 +2 +2+3 +3+3+4

-1 -1 -2 -2 -3 -3 -3 -4 -43000 4GB 6 13 20 26 33 40 46 53 60 66 1 2 3 4 6 7 8 9 10 12 +0 +1 +1 +2 +2 +3 +3'+4+4+5

-1 -1 -2 -2 -2 -3 -3 -4 -4 -43500 4GB 5 11 17 22 28 34 40i45 511"57 1 2 3 4 6 7 8 9 10'12 +0 +1 +1 +2 +2 +3 + 4 + 4 + 5 + 5

-11 -2 2 -3 -3 -4 -4 -5 -54000 5GB 5 10 15 20 25 30 35 40 45 50 1 2 3 4 6 7 8 9 10 12 +0 +0 +1 +1 +11+2+2+2+3+3

-1 -1 -2 -2 2 -3 -3 -3 -4 -44500 5GB 4 8 13 17 22 26 31 35 40 44 1 2 3 4 6 7 8 9 10 12 +0 +0 +1 +1 +11+2 +2+3+3 +3

-1 -1 -2 -2 -2 3 -3 -4 -4 -45000 5GB 4 8 12 16120 24 28 32'36140 1 2 3 4 6 7 8 9 10 12 +0 +0o+1+1+2 +2 + 2 + 3 + 3 + 4

-0 -0 -1 -1 -2 -2 -2 -3 -3 -45500 5GB 3 7 10 14118 21 25 29 32 36 1 2 3 4 6 7 8 9 10 12 +0 +0 +1 +1 +2 +2 +3 +3 +3 +4

-0 -0 -1 -1 -2 -2 -3 -3 -3 -46000 5GB 3 6 10 13 16 20 23 26 30 33 1 2 3 4 6 7 8 9 10 12 +01+0 +11+1 +2 +2 +3 +3+4+4

-1 -1 -2 -2 -3 -3 -4 -4 -5 -56500 5GB 369 112 1518 2124 27301 3 46 8 9 1 1 1 2 1 4 1 6 + 0 + + 1 + 1 + 2 + 2 + 3 + 3 + 4 +

_ _-1 -2 -2 - 2 - 3 31-4 1-4m

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0HASTYPOSITIO DEFLECTIO[HASTY POSITIOWl1UADRA1T HASTYMUZZLEVELOCITY

M109A2/3 CORRECTIONJSLATERALCORRECTIO91ELEVATIO1 CORRECTIOJS CORRECTIOINS(M/S)

M198 (L/R) (F/B)

155-AM-2i-.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

M107 (METERS) (IETERS) 11+.5 1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0

RAG 0 14 6 gD 1001I120f140 11601 80 1-200}20J40 160O801100 1120114016 180 1200] _________________

[.,,12040ILS MLS M LMU-2 1 - L S - - - _-

7000 5GB 2 5 8 11 3 1 17 20 22 2528 1 3 4 6 8 9 11 12 14 16 +0 +1 +2 +2 +3 +4 +4 +5 +6 +6

IIII -1 -2 31-31-4 -5 -56-61-7 -

7500 5GB 2 5 8 101 13 16 18 21 24 26 1 3 4 6 8 9 11 12 14 16 +0 +1 +2 +2 +3 +4 +5 +5 +6 7

121jA -1 -2 -33-41-5 -6 -7 -8 -9

8500 6WB 2 4 7 9 11 14 16 18 21 23 1 2 13 4 1 6 7 8 9 10 12 +0++1+1+2 +2 +3+4 +4 +55- -- 1 -2 -2 -3 -3 -4 -5 -5 -6 -6

9000 6WB 2 4 6 8 11 13 15 17 20 22 1 2 3 4 6 7 8 9 10 12 +0 +1 +1 +2 +3 +3 +4 +4 +5 +6---- 1 -2 -2 -3 -41-4 -5 -5 1-6 -

9500 6WB 2 4 6 8 10 12 14 16 18 21 1 3 4 6 8 9 11 12 14 16 +0 +1 +2 +3 +4 +5+5 +6+7+8

-1 -2 -3 -4 -5 -6 -6 -7 -8 -9

10000 6WB 2 4 6 8 10 12 14 16 18 20 1 3 4 6 8 9 11 12 14 16,+0 +1 +2 +3 +4 +5 + 6 + 6 + 7 + 8

Ia - - -1- -1--2--3 -4 -5 -6 -6 -7-8-9

10500 6WB 1 3 5 7 9 11 13 15 17 19 1 3 4 6 8 9 11 12 14 16 +0 +1 +2 +3 +4 +5 + 6 + 7 + 8 + 8

-- I--- _-11-2 -3 -4 -5 -6 -71-8-8-9

11000 6WB 1 3 5 7 9 10 12 14 16 18 2 4 6 8 10 12 14 16 18 20 +1 +2 +3 +4 +5 +6 +8 +9+10+11-2 -3 -4 -5--6 -7 -8-9-11 12

11500 7WB 1 3 5 6 8 10 12 13 15 17 1 2 3 4 6 7 8 9 10 12 +0 +1 +1 +2 +3 +4 + 4 + 5 + 6 + 6

- , , -1 -2 -3 -3 -4 -51-5 -6-7-7

12000 7WB 1 3 5 6 8 10 11 13 15 16 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +2 +31+4 +4+51+6+6

- -1 -2 -3 -3.-4 -5 - 5 . - 6 - 7 7

12500 7WB 1 3 4 6 8 9 11 12 14 16 1 3 4 6 8 9 1112 14 16 +0 +1 +2 +3 +4 +5 + 6 + 7 + 8 + 9

-1 -2 -3 -4 -5 -6 -7 -8 -9-10

13000 7WB 1 3 4 6 7 910 12 13 15 1 3 - 4 6 8 9 11 12 14 161+0 +1 +2 +3 +4 +5 + 6 + 7 + 8 + 9

I--- 1 -2 -3 - 4 - 5 - 6 I - 7 - 8 . L - 9

13500 7WB 1 2 4 5 7 8 10 11 13 14 2'4 6 8 10 12 14 16 18 20+1 +2 +3 +4\+6 +7 +8 +9+11+12

- - -2 -3 -4 -5--7 -8 -9 - 1 11 -3

14000 7WB 1 2 4 5 7 8 10 11 12 14 2 5 7 10 12 14 17 19 22 24 +2 +3 +5 +6 +8 +9 11 12+14+15

-1 -3 -5 -6 -7 -9 10 12-13-15

14500 8 1 2 4 5 6 8 9 11 12 13 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +2 +3 +4 +4 +5 +6 +7-1 -2 -31-3--4 -5 -5 -6-7-8

15000 8 1 2 45 6 8 9 1 0 1213 12 3 46 7 8 9 1 0 12 +0 + 1 + 2 + 2 +3 + 4 + 5 + 5 +6+

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HASTYPOSITIONOEFLECTION HASTYMUZZLEVELOCITYM109A2/3 CORRECTIONSLATERALCORRECTION HASTY POSITION(QUADRANT CORRECTIONS(M/S)

M198 (L/R) ELEVATIONCORRECTIONS155-AM-2 -.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

M107 (METERS) (METERS) +.5 +1.0 +1.5+2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0

R E I -C10 1 0 L 180 1 2 $1 061001180 200 f204 0 10O 0 1 0 11 0 1 0 1 12001_ - MILS MILS - =MILS

15500 8 1 2 3 5 6 7 9 10 11 12 1 2 3 4 6 7 8 9 10 12 +0 +1 +2 +2 +3 +4 +5 +5 + - s-II-1 -2 -3 -3 -4 -5 -6 -6 -

16000 8 1 2 3 5 6 7 8 10 11 12 1 3 4 6 8 9 11 12 14 16 +0 +2 +2 +4 +5 +6 +7 +8 + +10

15500 8 1 2 3 4 6 7 8 9 10 12 1 3 4 6 8 9 11 12 14 165H+0T+2 +3+4 +5 +6 +7 +8 +9-2 -3 -4 -45 -6 -7 -8 -9-1 0

17000 8 1 2 3 4 5 7 8 9 10 11 2 4 6 8 10 12 14 16 18 20 +1 +2 +3 +5 +6 +7 +9+10+11+12-22-3 -4 -6 -7 -8 10 11 -123

1 8 1 2 3 4 5 6 8 9 1 1 3 6 8 1 1 1 2 2 2 '2+ + +5 + + + 13+15 + 17 9-2 -4 -61-8101-12 14 15-1 -19

HASTYPOSITIONDEFLECTION HASTYMUZZLEVELOCITYCORRECTIONSLATERALCORRECTION HASTYPOSITIONQUADRANT CORRECTIONS(M/S)

M102 (L/R) ELEVATIONCORRECTIONS105-AS-2 -.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

_ _(METERS) (METERS-) +.5 +1.0 +1.5+2.0 +2.5 +3.0+3.5 +4.0 +4.5 +5.0RANGE HG 20 140 160180 1100 1120 1140 0801200 120J40 i 080oo100o20 1140 1160 1180z20 ._LMILS MISILLS - LS1000 5 20140 60 80 100 120 140 160 180 200 1 2 3 4 6 7 8 9 10 12 +0 +0 +0 +0 +0 + 0 1 +1 +1 +1

-- 1 -1 -1 -1 -1 -2 -21-

1500 5 13 26 40 53 66 80 93 106 120 133 1 2 3 4 6 7 8 9 10 12 +0 +0 +0 +0 +1+ l+1 +1++2 +2-- 1-1--1-1-2-2-2 -2

2000 5 1 0 20 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 12 3 46 7 8 9 10112+0 + 0 + 0 +1+1 +11+1+2 +2+-1 -1 -1 -1 -2 -2 -2 -2 -3 -3

2500 5 8 1164 03 0406048756 64 72 980 2 3 4 6 7 8 9 10 112 +0 +0 +10+1 +1 +2 +2I+2 +3 3 . -1 -1 1 -2 -2 -2 -2 - 3 -3

3000 5 6813 202 6 43 2404 6 5353 066 2 3 4 6 7 8 9 10 12 +0 +0 +1 +1 +2 +2 +2 +32+3+3- - -1 -1 -11-2 -2 -2 -3-31-3-

3500 5 5611 1 2 2 02 63 0 45 56057 2 3 4 6 7 8 9 10 124+ 0 +0-+ 1 +1 +2 +24+3 +3+4 +4-1 -1 -2 -2 -2 -3 -3 -3 -4 -4

4000 6 5 10t15720 2258305 4 0 45 5 0 1 2 3 4 6 7 8 9 10 12 +0 +0+1 +1 +14+2+ 2 + 2 + 3 +3-0 -0 -1 -1 -1 -2 2 -2 -3 -3

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HASTYPOSITIONDEFLECTION HASTYMUZZLEVELOCITY

CORRECTIONSLATERALCORRECTION HASTYPOSITION QUADRANT CORRECTIONS(M/S)

M102 .(L/R) ELEVATIONCORRECTIONS

105-AS-2 -.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 -4.5 -5.0

_________(METERS) (METERS) +.5 +1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0

2RANGECH 21401601801 O 114.l60 18012o0 20 o160 o18041100-1201140 11601180 120o...

MILSMILS MILS

4500 6 4 8 13 17 221 26 31 35 40 44 1 2 3 4 6 7 8 9'10 12 + 0 + 0 +1 +1 +1 + 2 + 2 + 2 + 3 + 3

- - --- 1 : -2 -2'-2 -3 -3 -3 -- 4

5000 6 4 8 12116 20 24 2832 36 40 1 2 3 4 6 7 8 9 10112 +0 +0 +1 +1 +1 +2 +2+3+3+3

-0 -0 -1 -1 -1 -2 -2 -3 -3

5500 6 317 10114 18 21 25 29 32 36 1 2 3 4 6 7 8 9810 12 +0 +0 +1+1 + 1 2 + 2 + + 3 + 3 + 3-1 -1 -2 -2 -3 -3 -3 -4 -4 -5

6000 6 316 10113 16 20 23 26 27 33 1 2 3 4 6 7 8 9 10 12 +0 +0 +1 +1 +2 +2 +2+3+3+4-1 -1 -2 2 -3 -3 -3 -4 -4 -5

6500 6 316 9112 15 18 21 24 25 30 1 3 4 6 8 9 11 12 14 16 +0 +1 +1 +2 +2 + 3 + 4 + 4 + 5 5-1 -2 -2 -3 -3 -4 -5 -5 -6 -6

mJ4

7000 6 2 5 8 11 14 17 20 22 24 28 1 3 4 6 8 9 11 12 14 16 +0 +1 +1 +2 +3+3 +4 +4 +56-1 -2 -2 -3 -4 -41-51-5 -6 -7

7500 6 2 5 8 10 13116 18 21 22 26 1 3 4 6 8 9 11 12 14 16 +0 +1 +1 +2 +3 +3+4 +5 +56

--- 1 -2--2 -3 -4 -4 -5-6-6-7

8000 6 2 5 7 10 12 15 17 20 21 25 2 4 6 8 10 12 14 16 18 20 +0 +1 +2 +3 +4 +5 +5 +6 +7 +8-1 -2 -3 -4 -5 -5 -6 -7 -8 -9

8500 6 2 4 7 9 11 14 16 18 20 23 2 5 7 10 12 14 17 19 22 24 +0 +2 +3 +4 +5 +6 +7 +8 +9+10-2 -3 -4 -5 -6 -7 -8 -9 10-11

9000 7 2 4 6 8.11 13 15 17 18 22 113 4 6 8 9 11 12 14 16 +0 +1 +2 +2 +3i+4 + 4 + 5 + 6 + 6

-1 -2 -2-3-4-4 4-5-6-619500 7 2 4 6 8 1 0 11 2 14 16 18 21 1 3 4 6 8 9 11 12 14 16 +0 +1 +2 +2 + 3 + 4 + 4 + 5 + 6 + 6

-1 -2 -3 -3 -4 -5 -5 -6 -7 -7

10000 7 2 4,5 8 10 12 14 16 17 20 2 4 6 8 10 12 14 16 18 20 +0 +1 +2 +3 +4 +5 +6 +7 +7+8-1 -2 -3 -4 -5 -6 -7 -7 -8 9

10500 7 1 3 5 7 9 11 13 15 16 19 2 5 7 10 12 14 17 19 22 24 +1 +2 +3 +4 +5 +6 +7 +8 +9+10

-2 -3 -4 -5 -6 -7 -8 -9 10-11

11000 7 1 3 5 7 9 10 12 14 15 18 3 6 10 13 16 19 22 26 29 32 +1 +2 +4 +5 +7 +8 1012 +3+14-2 -4 -5 -6 -8 -9 -11 12 -14-15

a - *s u m -. . . . . . . m

4

0

0

it * 3) 4p





APPENDIX C

FIRE DIRECTION CENTER EQUIPMENT

CONTENTS OF FIRE DIRECTION SETS, ARTILLERY

NATIONALSTOCK

ITEM NUMBER

FM 6-40

QUANTITY

Fire direction set 3, artillery, 30,000 meters maxrange (LIN H55843); 19200, consisting of thefollowing components:

Carrying case, field artillery firedirection center

equipment: canvas, 50 inches long, 40 inches high,8 inches thick, folded;

Drawing board and trestle: 48 inches long, 36 incheswide, nonslope, folding trestle, 36 inches high;

Plotting sheet: 1,000-meter grid, 47 inches long,35 inches wide;

Protractor, fan, range deflection, 30,000 meters range,11834239 (19200).

Fire direction set 4, artillery, 15,000 meters

max range (LIN H55706), consisting of thefollowing components:

Carrying case, field artillery fire direction centerequipment: canvas, 45 inches long, 33 inches high,8 inches thick, folded;

Drawing board and trestle: 42 inches long, 31inches wide;

Plotting sheet: 1,000-meter grid, 41 1/2 inches long,30 inches wide;

Protractor, fan, range deflection, 25,000 meters range.

1290-00-299-6892

1290-00-694-5190

6675-00-248-1244

7530-00-656-0812

1290-00-266-6891

1290-00-299-6893

1290-00-694-5191

6675-00-248-1243

7530-00-656-0813

1290-00-266-6890

CONTENTS OF PLOTTING SET, ARTILLERY FIRE CONTROL

NATIONALSTOCK

ITEM NUMBER 'QUANTITY

Plotting set, artillery fire control (line itemno P09818), consisting of the followingcomponents: 6675-00-641-3630

1 set

I a

1 ea

12 ea

1 ea

1 set

1 ea

1 ea

12 ea

1 ea

1 set

C-1



FM 6-40

NATIONAL STOCK'ITEM NUMBER QUANTITY

Chest, plotting equipment: command post,81349 C-12044, D7242-1

Map tack: metal, spherical head, 100 per box:FED spec FF-T-51, type 1Black, 0.25-inch head, steel pin, 0.50 inch long

Blue, 0.25-inch head, steel pin, 0.50 inch long

Green, 0.25-inch head, steel pin, 0.50 inch long

Red, 0.25-inch head, steel pin, 0.50 inch long

Black, 0.25-inch head, steel pin, 0.625 inch long

Pad, writing paper: ruled-two sides, white, 10 1/2 incheslong, 8 inches wide, 100 sheets per pad, 12 pads perpackage, 81348 UU-P-21

Paper, tracing: high transparency, white:Substance 25 to 29 per 1,000 sheets of 17 x 22 inches.Basic size 18 inches long, 12 inches wide, 100 sheetsper pad81348 UU-P-00561 type III

Substance 31 to 35 per 1,000 sheets of 17 x 22 inches.Basic size 20-yd roll, 21 inches wide.81348 UU-P-561 type III

Pencil: thin lead, wood-cased,class A:Blue 76364 mephisto 1345Green 81348 SSP201Orange 75364 mephisto 1343Red 75364 mephisto 1340

Drawing, black, w eraser, FED spec SS-P-1605no H:No HNo 3HNo 5H

General writing, black, thin lead, medium hard-ness, no 2, w eraser, 81348 SS-P-166, type IV

Glazed surface marking, extra thick lead,paper-cased:Black, 12 per package

class CBlue, 12 per package

class ARed, 12 per package

class B

6675-00-049-5132

7510-01-045-3527

7510-01-046-5086

7510-01-045-3528

7510-01-045-3529

7510-01-046-5087

7530-00-285-3038

7530-00-235-4033

7530-00-236-9305

7510-00-233-20277510-00-264-46107510-00-189-78697510-00-233-2021

7510-00-264-46147510-00-189-78817510-00-189-7883

7510-00-281-5234

7510-00-240-1526

7510-00-436-5210

7510-00-174-3205

C-2

1 ea

2 boxes

2 boxes

2 boxes

2 boxes

2 boxes

1 pkg

1 pad

1 roll

dozdozdozdoz

1 doz1 doz2 doz

2 doz

1 doz

1 doz

1 doz



NATIONALSTOCKNUMBER'

Pencil pointer: flint, 7 1/4 inches1 1/4 inches wide, 1/8 inch thick,81348 SS-P-551, type II

Plastic sheet: cellulose acetate, transparent, matte

finish 1 ide, colorless, 0.0075 inch thick, 20 inches

wide, 50-ft roll,81348 L-P-504, type I

Plotting needle: red head, tapered shaft, 11/16 inch

long, 0.020- to 0.030-inch diameter; 1 1/8 incheslong, 4 per folder (package)81349 FF-T-51

Protractor, semicircular: brass, 4 1/4 inch, 1-degree

graduations, numbered 0 to 180 degrees,81348 GG-P-681, type I, class A, style 1

Plastic; 16-inch diameter, graduation units, mils,

and meters, scales 1 to 25,000 and 1 to 50,000, 10-mil

graduations numbered 100 to 3,100 mils,

81349 MIL-P-20385, type I

Scale, plotting:Aluminum, flat, eight bevel, hollow square shape,

graduationunits, meters, and yards; scales 1 to

25,000 and 1 to 50,000; 4 inches square outside and2 inches square inside;81349 MIL-S-10987

Wood and plastic, triangular, relieved facet,

graduation units, 1 to 25,000 yd, 1 to 25,000 meters,

1 o 50,000 and 1 to 62,500 inches and centimeters,12 inches long,81348 GG-8-161/7, shape D, otice 2

Sharpener, pencil: pocket size,draftsman's point cut,75364 catalog no 1000

Shears, straight trimmers: steel blade and handle,

sharp pointed blades, 9 inch,81348 GGG-S-00278, type I, class 1, style A

7510-00-237-4926

9330-00-282-8324

7510-00-851-9354

6675-00-641-3166

6675-00-556-0118

6675-00-283-0018

6675-00-283-0040

7520-00-227-1451

5110-00-161-6912

ITEM

FM 6-40

QUANTITY --

2 ea

1 roll

12 pkg

1 ea

1 ea

4 ea

2 ea

2 ea

1 ea

C-3



FM 6-40

APPENDIX D

EMPLOYMENT OF AEMOR UNDDDECT FHRE

D-1. PURPOSEAlthough tanks are traditionally direct fire

weapons, under exceptional circumstances,the force commander may decide to use themin an indirect fire role. The tank unit may beattached to the field artillery unit, or it may begiven a reinforcing role. This appendixdiscusses the gunnery techniques to be used

and otherfactors to be considered by the field

artillery crew member when the tank unit isunder field artillery control.

D-2. REQUIREMENTS

a. Because of the small bursting radius ofthe high-velocity, flat-trajectoryammunition and the short tube life of themain gun, tanks normally are not used in thefield artillery (indirect fire) role.

b. When the tank unit is attached to orreinforcing a field artillery unit, the fieldartillery unit is responsible for fire control,communications, and survey. If the tank unitis attached, the field artillery unit is alsoresponsible for ammunition, fuel, rations,and other supplies.

c. Whether attached or reinforcing, thetank unit must be able to revert immediatelyto its primary role. Therefore, the tank unit'sbasic load of ammunition should not be usedin the indirect fire role. If possible,ammunition should be prestocked for thispurpose.

d. For information on the mission andtactical employment of tank units, on thecharacteristics of tanks and tank fire controlequipment, and on direct fire with tankweapons, see the 17- and 71-series fieldmanuals.

e. The normal position area width of atank platoon front is about 150 meters. For

tanks, a parallel sheaf produces an effectivepattern of bursts with this position areawidth. For position areas of different widths,it is necessary to adjust the width'of the sheafto obtain the most effective pattern of bursts.

D-3. AMMUNITON

The HEP and WP projectiles are availablefor the 105-mm tank guns (M60, M60A1,M60A2, M60A3, M48A5, and M1 tanks).Separate fuzes are not available. Allprojectiles are fixed with PD fuzes.

Note. See TM 43-0001-28 for furtherinformation on ammunition.

D-4. OBSERVERPROCEDURES

Field artillery observer procedures are used

in conducting indirect fire with tanks.

D-5. FIRE DIRECTION

a. Fi r ing Char t . The location of each

tank platoon is plotted on a firing chart. Adeflection index is constructed at 0 deflectionby orienting the left edge of the arm of theRDP in the direction on which the tanks arelaid and drawing the index on the chart at thecenter graduation of the mil scale on the arc.The RDP is numbered for reading shifts of

500 mils right or left of the direction of lay asfollows:

(1) Number the center graduation 0.

(2) Number each succeeding 100-milgraduation to the right Li through L4 andeach succeeding graduation to the left R1

D-1



FM 6-40

through R4. The last graduation on each endneed not be numbered. For reading shiftsgreater than 500 mils, additional indexesmust be constructed. If tank weapon firingtables are not available to the FDC, the tankunit usually fires only observed fires in theindirect role. If

a TFT is available, aregistration should be conducted andcorrections applied. Corrections sent by theobserver during adjustment are plotted on thetarget grid as outlined in chapter 5. The -armor fire control officer (FCO) will computea range K for his weapons..

b. Fire Commands.

(1) Fire command information is sentfrom the FDC to the tank unit FCO, who is thetank platoon commander and is responsiblefor tank fire. The FCO

converts thisinformation to a platoon fire command andsends it to the tanks. The FCO requires therange from the platoon to the target, thedifference in altitude, the direction, and thetarget description.,

(a) The range information is given tothe nearest 100 meters.

(b) When the target is at a differentaltitude from that of the tank, an angle of siteis computed, in mils, and is included in thefire

commands. The comp site forhigh-velocity guns is negligible and isignored.

(c) The direction information is givenin terms of a reference point. In the indirectfire role, the tanks are laid on an azimuth.This azimuth is considered the referencepoint. When the tank is laid, the azimuthindicator is zeroed, and directions are givenas right or left of the reference point. Aimingposts may be set out and aligned on acommon deflection (usually at 0) or 2,600 or

2,800 mils to the right front. Since the tankdoes not have a panoramic sight, the aimingpost deflection is merely an offset angle.During lulls in the firing, the gunner checks atank's displacement by using the aimingposts. He does not traverse the turret (tube)back to the aiming circle.

(d) The nature of the target isannounced to the tanks as a portion of theirfire command.

(2) Once the fire control officer has thefiring information of range, altitude,direction, and target description, he mustconvert these data so that a fire commandcan be sent to the tanks.

(a) The range information must bereceived as a quadrant reading, whichincludes angle of site and the elevationcorresponding to the range.

(b) The direction command must bemodified so that it can be placed on the tank'sfire control instruments.

(c) An example of a platoon firecommand issued by the fire control officer isshown below:

PLATOONHEPMORTARS FIRING3127 RIGHTQUADRANT +430AT MY COMMAND, FIRE

o PLATOON. The normal method ofemploying tanks in an indirect fire roleis y platoon (five tank guns). To alertall firing weapons that they will fire, thecommand is PLATOON. To alert allpieces to follow with one tank firing inadjustment, the command

is PLA-TOON ADJUST, NUMBER THREE(the number three piece firing inadjustment).

o HEP. The ammunition command issimilar to that for field artillery exceptthat the word shell is omitted.

o MORTARS FIRING. The nature ofthe target is announced to the tank unitas a portion of the fire command.

o 3127 RIGHT. This portion of the firecommand is the direction and must becomputed by the FCO by use of thedirection information sent from theFDC and drift data in tank firing tables.Once the direction of the gun has beencomputed and drift accounted for, thedata must be converted to a reading thatcan be applied to the tank azimuthindicator. The tank azimuth indicator isnumbered left from 0 to 3,200 mils and

D-2

S



FM 6-40

from that point again from 0 to 3,200mils. Because of this, a direction and anazimuth to the left of the reference pointare the same, but to the right, the twonumbers are different and always total3200. A direction RIGHT or LEFTmust be included in the command, sincethis determines which direction alongan axis the tubes point.

QUADRANT +430. The FCOobtains the superelevation angle fromthe firing tables and combines it withthe angle of site announced by the firedirection center. The tank weapons maybe laid for elevation by using either thegunner's quadrant or the elevationquadrant. Since the range of most tankweapons is limited by the inability to

elevate to high angles, it may benecessary either to dig in the rear of thetanks or to place the tanks on a rampthat slopes away from the direction offire.

AT MY, COMMAND, FIRE. Thecommand AT MY COMMAND tellsthe tank crew to notify the FCO when itis ready to fire. The command to openfire is FIRE. In tank gunnery, thiscommand is the last element in the

sequence of a firecommand, because the

tank gunner is trained to hold his fireuntil the command FIRE is received.

Note. When required, other ire commandsused by the artillery (for example, pieces to

fire and method of fire) are sent to the tanksin the simplest and most understandablemanner. Common sense and liaison betweenartillery and armor should overcomedifficulties caused by lack of formalprocedure. These difficulties are furtheralleviated through the use of prearrangeddata sheets.

D-5. ALTERNATE METHODS

Other methods that may be used in

controlling the indirect fire of tanks are asfollows:

a. Independent Method. The tank

unit uses fire direction equipment andpersonnel organic to the tank battalion to

form, with artillery assistance, a fire

direction center.

b. Semi-independent Method. The

tank unit handles its own indirect fire

missions from prearranged data sheets.Survey control, meteorological computa-t ions, prearranged data sheets, an d

assistance in laying the tanks may be

provided by the supported artil lery.

Interdiction and harassing missions are the

types of missions handled most effectively byuse of data sheets.

D-3



FM 6-40

APPENDIX E

INTERNATIONAL STANDARDIZATIONAGREEMENTS

E-1. DEFINITION

Standardization agreements (STANAGsand QSTAGs) are international agreementsdesigned to facilitate allied operations. Uponratification by the United States, thesestandardization agreements are bindingupon the United States forces (entirely orwith exceptions as noted).

E-2. STANAG

A STANAG is an international agreementwherein the nations of a specific treatyorganization agree to certain operationalactions to enhance the allied operation. Thestatus of STANAGs associated with fieldartillery cannon gunnery, which the UnitedStates agrees to implement and promulgate,are categorized as in table E-1.

Table E-1. Standardization agreements.

STANAG SUBJECT STATUS

2144 Call for Fire Procedures USAFAS changes to US-ratifiedSTANAG 2144 are included in thispublication.

2867 Radio-Telephone Procedures for the USAFAS changes to US-ratifiedConduct of Artillery Fire STANAG 2867 are included in this

publication.

2875 Calls for Destruction, Smoke, llumina- USAFAS changes to nonratified

tion, and Danger Close Missions (draft) STANAG 2875 are included inthis publication.

4119 Adoption of Standard (Common) Artil- ABCA ratified.lery Firing Table Format

E-1



FM 6-40

E-3. QSTAGA QSTAG is an international agreement

wherein the ABCA nations (United States,United Kingdom, Canada, Australia) form aquadripartite alliance and agree to certain

operational and procedural techniques toenhance the allied operation. Status ofQSTAGs associated with field artillerycannon gunnery, which the United Statesagrees to implement and promulgate, arecategorized in table E-2.

Table E-2. Quadripartite standardization agreements.

QSTAG SUBJECT STATUS

220 Adoption of Standard (Common) Artil- ABCA ratified.lery Firing Table Format

224 Manual Fire Direction Equipment, ABCA ratified.Target Classification, and Methods ofEngagement for Post-1970

225 Call for Fire Procedures USAFAS changes to US-ratifiedQSTAG 225 are included in thispublication.

246 Radio-Telephone Procedures for the USAFAS changes to US-ratifiedConduct of Artillery Fire QSTAG 246 are included in this

publication.

E-4. IMPLEMENTATIONThe doctrine, procedures, and techniques

promulgated in the above STANAGs andQSTAGs are implemented in this publicationonly as indicated in the status shown for eachSTANAG/QSTAG. As ratification detailsoccur, specifically concerning thoseagreements that have been changed byUSAFAS, subsequent implementation andpromulgation action will be madeaccordingly. Tables E-3 through E-6 areexamples of basic cannon gunneryprocedures as promulgated in the variousQSTAGs and STANAGs and are includedhere to allow member nation units to operatewith United States Army units when thispublication is the only reference available.

E-2



FM 6-40

Table E-3. Example of call for fire other than US.

SERIAL GENERAL HEADING SPECIFIC EXAMPLE

1 Observer's identification 20, THIS IS 21

2 Warning order FIRE MISSION BATTERY

3 Location of target including direction GRID 123456ALTITUDE 100DIRECTION 1640

4 Target description PLATOON DUG IN ON RIDGE200 BY 50, ATTITUDE 4850

5 Method of engagement

a. Type of engagement DANGER CLOSE

b. Trajectory HIGH ANGLE

c. Ammunition VT IN EFFECT 10 ROUNDS

d. Distribution of fire OPEN

6 Method of fire and control AT MY COMMANDTWO GUNS PLATOON RIGHTADJUST FIRE

Table E-4. Example of US call for fire.

SERIAL GENERAL HEADING SPECIFIC EXAMPLE

1 Observer's identification A57, THIS IS A71

2 Warning order ADJUST FIRE, SHIFT AB2176

3 Location of target DIRECTION 5210, LEFT 380,ADD 400, DOWN 25

4 Target description PLATOON DUG IN ON RIDGE200 BY 50, ATTITUDE 1650

5 Method of engagement

a. Type of engagement DANGER CLOSE

b. Trajectory HIGH ANGLE

c. Ammunition VT IN EFFECT 10 ROUNDS'

d. Distribution of fire OPEN

6 Method of fire and control TWO GUNSAT MY COMMAND

'US observer will not specify number of rounds.

E-3



FM 6-40

Table E-5. Example of an area target engaged by a battery of US artillerywhen the observer is from another member nation.

3 GRID 321456, ALTITUDE 1204 DIRECTION 51005 VEHICLES PARKED IN W O O D S

200 BY 100, ATTITUDE 28506 ADJUST FIRE7 (Battery identification),

6 ROUNDS ZP7I 58 SHOT9 RIGHT 1 O , DD400 2

10 SHOT11 DROP 200

12 SHOTQ13 DROP 100

14 SHOT

15 DROP 50, FIRE FOR EFFECT

16 SHOTROUNDS COMPLETE

17 END OF MISSION. THREEVEHICLES BURNING

Table E-6. Example of an area target engaged by a battery of artillery (not US)when the observer is from the US.

SERIAL OBSERVER'S REQUEST REPORTS TO OBSERVER

1 (Observer's identification)

2 ADJUST FIRE

3 GRID 3214564SIX ARMORED PERSONNEL

CARRIERS

E-4

,. r' ... - ... : : : - = ." ,, l " .- 'r'' :

t l ii'it -,F.;"m'., -~ri~ ,L:.._t . . . , . . . _. ..



FM 6-40

Table E-6. Example of an area target engaged by a battery of artillery (not US)

when the observer is from the US (continued).

OBSERVER'S REQUEST

5

6

7

8

9

10

1112

13

14

15

II_-_J aML

REPORTS TO OBSERVER

(Battery identification)6 ROUNDS

SHOT

SHOT

SHOT

SHOT

SHOTROUNDS COMPLETE

SERIAL

DIRECTION 1680,RIGHT 120,ADD 400

DROP 200

DROP 100

ADD 50, FIRE FOR EFFECT

END OF MISSION, I

TWO PERSONNEL CARRIERSDESTROYED

E-5



FM 6-40

APPENDIX F

STANDARDIZED PROCEDURES

F-1. IDENTIFICATIONThis appendix contains the following standardized procedures relevant to

cannon fire direction:

SUBJECT PAGE

Surveyed Firing Charts5-1

Firing Chart NumberingPositioning and Orienting the Target Grid

Plotting Points on the Firing Chart

Target Symbiology on Firing ChartsEstablish Azimuth Indexes on Firing Charts

Establish Deflection Indexes on Firing Charts

Determine Initial Chart DataElements and Format for Announcing Chart Data

Chart Data TolerancesManual Chart Verification

Muzzle Velocity Management 11-1

M90 Velocimeter Work SheetMuzzle Velocity RecordMuzzle Velocity Log

Computer's Checklist13-4

Ammunition StatusWeapons DataPlanned Firing Data

Prepare and Update Firing Charts .. G-1

Attack Targets G-4

Determine and Apply Registration Corrections G-7

Initialize BCS for Operation G-0

Determine Replot Data G-12

Determine and Apply Met Corrections G-14

Establish and Maintain Communications' G-17

Prepare for Dedicated Battery Operations. G-21Manage and Apply Muzzle Velocity Information. G-23

Initialize the Hand-Held Calculator for Operation G-24Initialize FADAC for Operations . .. G-26

Determine Special Corrections - ....... - - G-28

Note. The above procedures are denoted by an asterisk (*) in the text. _

I

F-1



FM 6-40

F-2. APPROVED FDC LAYOUTSIncluded in this appendix are the approved layouts of the battery FDCs in

the M577 and M561 command post vehicles. Detailed drawings anddiscussions are available from:

Commandant

US Field Artillery SchoolATTN: ATSF-GAFort Sill, OK 73503

FRONT

FADAC CABLE MOUNT

4.2-KW 3-KWDRIVER'S GENERATOR GENERATOR

HATCH

EQUIPMENT HATCH COVER 3-KWTORAGE 3KS TA E GENERATORBASKET

E3N

I mmnTnACK

COMADE'.LHATCH

Figure F-1. External top view of battery FDC in M577A1 command post vehicle.

F-2



FM 6-40

RADIO SHELF .(SEEBAERY COMPUTER

'-I

COMMUNICATIONS SYSTEM WITH

DETAIL) TABLE ON MOUNT 0

FREQUENCIES CHART

WEAPONS RACK FRONT0

4 70-n

CANVAS CHART OPERATOR'S KIT 0 0 MRAMP

SOAE NBC EQUIPMENT

MAP BOARDSHELF

Figure F-2. First tier of BCS-equipped battery FDC in M577A1 command post vehicle.

Figure F-3. Second tier of BCS-equipped battery FDC in M577A1 command post vehicle.

F-3



FM 6-40

MX 7778

Figure F-4. Left side view of BCS-equipped battery FDC in M577A1 command post vehicle.

-BOTTOM ANDTOSHLTOPTOP SHELFSAFE RADIOSHELF i FA c......

(SEE FFADACIPCOMMUNICATIONS WITH TABLE EQUIPMENT

DETAIL) ON MOUNT i STORAGE

S FREQUENCIES CHART

t,WEAPONS RACK ...

CANVAS CHART OPERATOR'S KIT PLOTTINGCHEST

LH STORAGE N B C EQUIPMENT

Li 3-BY 4-FOOT CHART COMPUTER11SITSHERE

MAP BOARD

STATUS CHARTS

FRONT

KFIREORDER/FIRE COMMANDS

ELEVATEDSTORAGE

SHELF

Figure F-5. First tier of FADAC-equipped battery FDC in M577A1 command post vehicle.

F-4

RAMP

SMALL UNIT

11

I



FM 6-40

SHELF JOINT

SUPPRESSOR -'

SAFE -

RAMP I

FIRE

SITUATION MAP

EQUIPMENTISTORAGEI

AN/VRC-46CALL SIGNS

FADAC WITH TABLEON MOUNT

PLOTTINGCANVAS CHART OPERATOR'S KIT CHS

NBC EQUIPMENTSTORAGE

FIRING CHART ON10-INCH SLANT

COMPUTER'S CHAIRIS MOUNTED HERE

Figure F-6. Second tier of FADAC-equipped battery FDC in M577A1 command post vehicle.

F-5

FADAC MOUNTED TOEDGE OF THE FIRST

SHELF

FRONT

STATUS CHARTS

SECOND-TIER

STORAGE

FigureJE-7. Left side view of FADAC-equipped battery FDC in M577A1 command post vehicle.



NBC EQUIPMENT STORAGE BOX(ACTS AS FOOTREST FOR COMPUTER)

PLOTTING CHEST

CANVAS STORAGE BA G

FIRING CHART ON 10-INCH SLANT

SITUATION MAP

-U COMPUTER'S I-MODULE

STORAGE

.. ..... I

Figure F-8. Right side view of BCS- or FADAC-equipped battery FDC in M577A1 command postvehicle.

an

0-I

Figure F-9. Sample computer's desk made from a footlocker for M561 command post vehicle.

I wrr twr I -r'.-I .

FM 6-40

*0

IL I = i

F-6

M\Arn-M r--lI

11



FM 6-40

MOUNTCOMPUTER'S

DESK HERE

STEPS

F-7

m

Figure F-10. Top view of BCS-equipped battery FDC in M561 command post vehicle.

BATTERYCOMPUTER

UNIT OPERATOR

SITUATIONMAP w



FM 6-40

M561 (GAMA GOAT)

R AT E L O C H A I R RATELO

TABLE

RADIO HORIZONTAL a(CF 2) CONTROL i = B

OPERATOR 0 f RADIORADIO CHART 9 (CF 1) aADIO0

(FD 1)]C= =0

SITUATION MAP _

WHEELWELL COMPUTERoCHAIR BOX

TA-312/PT

TAILGATE J (REMOTE)

11 DR-8_

CHAIR - L-STEPS

A A A %

CHECK CHART

TRAILERSECTION/PERSONAL

EQUIPMENT STORAGE

Figure F-i11. Top view of manual FDC in the M561 command post vehicle.

F-8



Appendix G

HOW TO TRAIN FIRE DIRECTIONCENTER PERSONNEL

G-1. RESPONSIBILITYTraining the FDC personnel involves

teaching and sustaining proficiency inindividual and collective skills that the FDCneeds to accomplish its mission. Thecommander is responsible for developing andimplementing the best mix of individual andcollective training that will help soldierslearn and sustain proficiency in the requiredskills. The levels of training are as follows:

a. Field training exercise (FTX)-alive-fire exercise.

b. Situational training exercise (STX)-an ARTEP task.

c. Crew drill-an ARTEP subtask (acollective training task).

d. Individual task-a soldier's manualtask.

G-2. FDC CREW DRILLS

a. Crew training drills provide a unit withpractical and efficient methods to facilitateand integrate individual and collectivetraining. These drills consist of standardizedtechniques and procedures that facilitate theperformance of the subtask.

b. Drills have traditionally been used as

an effective method of integrating individualand leader skills at the lowest echelon toenable personnel to perform collective tasks.Drills are considered the most effectivemethod of training FDC subtasks, becausedrills reinforce individual task proficiencywhile preparing the FDC section for morecomplex collective tasks.

c. The following crew drills have beenprepared by the United States Army FieldArtillery School. They are included as asource for training. Other drills may be

developed by the unit to meet trainingguidance provided by the commander. Thedrills may be trained in garrison and in thefield. Wherever trained, these drills offermany advantages such as the following:

(1) They assist inexperienced juniorleaders to plan, prepare, and implementtraining.

(2) They allow soldiers to practice theirindividual skills and teach them how, when,and where to use these skills during unitperformance of ARTEP tasks.

(3) They minimize training costs andresources.

*G-3. PREPARE AND UPDATEFIRING CHARTS

a. General. This drill is an integralpart of the battalion training system and wasdeveloped from the ARTEP and soldier'smanuals. It trains ARTEP 6-100 subtask3-1-6-lb. It applies to all FADAC/manualunits.

b. Prerequisites. Certain crew drills,ARTEP tasks, and individual skills must bemastered before this drill can be trained. Thepretraining requirements include thefollowing:

(1) ARTEP subtask: 3--6-1

(2) Individual soldier's manual tasks:

061-280-1000

061-280-1001

061-280-1004

(3) References:

ARTEP 6-100FM 6-13E1/2/3

G-1

FM 6-40



FM 6-40

c. Practice. Following pretraining, thesection must practice this drill to achieveinitial proficiency. After initial proficiencyhas been achieved, sustainment trainingevery 4 months is recommended. Morefrequent training may be necessary if the unithas a high turnover of personnel, infrequentrelated training, loss of key personnel such aschief computer/computer, or unit-peculiarproblems that degrade drill proficiency.

d. Recommended Training Support.

(1) Personnel and equipment. Abattery FDC section TOE and a battery FDCsection crew are required to train this drill.

(2) Time r equ i rements . It isestimated that the battery FDC section crewwill require 2 hours of initial training and 30minutes of sustainment training.

(3) Training area requirements.Each FDC section undergoing training willrequire a 50- by 50-meter area foremplacement of the section vehicle or for aclassroom of sufficient size to accommodatethe TOE equipment and the crew.

(4) Standards. The drill standards arebased on the following assumptions:

(a) All TOE personnel and equipmentare available and operational.

(b) All personnel are MOS-qualified.

(c) Unless otherwise specified in theconditions, no other competing actions areongoing, and weather conditions arefavorable.

e. Training Procedures. The chiefcomputer will have the FDC crew occupy thetraining area. When this has been done, hewill immediately direct the section to preparethe firing chart.

(1) Preparing the firing chart. To beproficient at this task, the section should betrained to construct firing charts whensurvey control is available and when surveycontrol is not available, but a map isavailable. The chief computer will provideplotting sheets, plotting equipment, andpertinent data. Time and drill sequence willbegin when the section has occupied theposition/training area.

(2) Updating the firing chart. Theupdate phase of the drill will follow thepreparation phase. The section should betrained to update firing charts on the basis ofthe following conditions:

(a) Survey control is brought to thebattery location after a map spot has beenestablished.

(b) The battery is required tomaintain a 6,400-mil firing capability.

(3) Evaluation. The chief computerevaluates the actions of the section and notesall training deficiencies and omissions. Anafter-action review is given to the FDCsection after the drill has been completed. Thedrill is trained until no deficiencies are notedby the chief computer.

Table G-1. Prepare and update firing charts drill.

TASK'CONDITIONS TRAINiNG/EVALUATION STANDARDS

Battery has occupied a positionarea. Plotting sheets andplotting equipment are avail-able.

Number the grid on the firing chart. Plot knowncritical points; for example, OPs, battery locations,and radars.

Construct azimuth and deflection indexes.

Verify firing chart construction.

±3p4 deflection/azimuth

±30 meters range

S

G-2



FM 6-40

Table G-1. Prepare and update firing charts drill (continued).

TASK CONDITIONS________ I I'

CHIEF COMPUTER

Issue order to prepare/update firing charts.

Verify the preparationof firing charts.

HCO

If FADAC is not avail-able, construct a firingchart.

Transfer from a map-spotted firing

The FDC section and equipmentare in position and areoccupying the battery area.

The FDC section and equipmentare positioned, and charts arebeing prepared.

You will be given-

o A grid sheet.

o The number for the lowerleft-hand corner of the chart.

o The coordinates and

altitudes of three firing batteries

and other critical points.

o The azimuth of lay andreferred deflection informationfor the batteries.

o An RDP.

o An aluminum plottingscale.

O Plotting pins.

o Pencils and an eraser.

o A map indicating the zone

of action of the supported unit.

You will be given all chartinformation including surveyedgrid coordinates and altitudes,

I TRAINING/EVALUATION STANDARDS

Transfer from a map-spotted firing chart to asurveyed firing chart without error within 8minutes.

G-3

This drill should be completed within 8 minutes ofoccupation of the position to allow the section to

process calls for fire.

During occupation of position, direct the personnelto establish and maintain the FDC. Firing chartsshould be prepared as soon as possible.

Organize the section beforehand to ensure rapidand orderly occupation.

Assign duties and ensure that tasks are

understood.

Assign section priorities for preparation.

Ensure section members are thoroughly

familiar with unit and section SOPs.

Ensure chart operators have the correct data.

Announce the coordinates found in the lower

left-hand corner of the chart.

Ensure firing charts are constructed properly.

Ensure FADAC/chart verification is performed.

Number the grid lines for easting and northing.

Plot, tick mark, and label locations within ±30meters of the true location.

Construct and label the primary deflection indexfor each of the firing batteries within ±3 mils.

Construct and label azimuth indexes for OPs andradars within +3 mils.


Set up the chart within 8 minutes of receipt ofinformation for the battery. Complete the firingchart for all locations within 14 minutes.



FM 6-40 ITable G-1. Prepare and update firing charts drill (continued).

TASK

chart to a surveyedfiring chart.

VCo

CONDITIONS

the range and range to thefired-on targets, and the newazimuth of fire.

Construct a firing chart. You will be given-

Transfer from a map-spotted firing chart to asurveyed firing chart.

o A grid sheet.

o The number for the lowerleft-hand corner of the chart.

o The coordinates andaltitudes of three firing batteriesand other critical points.

o The azimuth of lay andreferred deflection informationfor the batteries.

o An RDP.

O An aluminum plottingscale.

o Plotting pins.

o Pencils and an eraser.

O A map indicating the zoneof action of the supported unit.

You will be given all chartinformation including surveyedgrid coordinates and altitudes,the range and range to thefired-on targets, and the newazimuth of fire.

TRAINING/EVALUATION STANDARDS

Note. If FADAC is not available in the FDC, thev HCO will construct andmaintain the primary firing

chart and determine chart data. If FADAC isavailable, the HCO will operate the FADAC.

Number the grid lines for easting and northing.

Plot, tick mark, and label locations within +30meters of the true location.

Construct and label the primary deflection indexfor each of the firing batteries within +3 mils.

Construct and label azimuth indexes for OPs andradars within +3 mils.


Set up the chart within 8 minutes of receipt ofinformation for the battery. Complete the firingchart for all locations within 14 minutes.

Transfer from a map-spotted firing chart to asurveyed firing chart without error within 8minutes.

Note. If FADAC is not available in the FDC, theVCO's chart becomes the check chart. The VCOdetermines site. If FADAC is available, the VCO'schart becomes the only chart and will be used inconjunction with FADA C in the fastest method fordata determination.

* G-4. ATTACK TARGETSa. General. This drill is an integral

part of the battalion training system and wasdeveloped from the ARTEP and soldier'smanuals. It trains ARTEP 6-100 subtask3-1-6-2 or 3-1-6-7. It applies to all units.


(1) ARTEP subtask: 3-1-6-3 or 3-1-6-8


061-280-1001

061-280-1010

061-280-1020061-281-1001

061-281-2001

(3) References:

ARTEP 6-100FM 6-13E1/2/3FM 6-141-1FM 6-141-2FM 101-60 series

G-4

I



Table G-2. Attack targets drill.

TASK CONDITIONS [TRAINING/EVALUATION STANDARDS

Fire DirectionOfficer

Determine method oftarget attack.

Issue battery fire order.

Process battalion fireorder (FADAC/manual).

A fire mission has beenreceived. Commander's targetattack guidance, weapon/ammunition status, andsituation are known. The level ofcontrol has been established.Fire order standards have beenposted.

Target location and descriptionhave been received. Com-mander's attack guidance isknown.

Target attack analysis has beencompleted. Battery fire orderstandards have been des-ignated.Battery has received a battalionfire order.

Maintain current weapon, ammunition, and

situation information.

Determine whether or not to attack the target.

Determine effects desired and munitions required.

Use the GMET or JMEM to determine the

following:

o Precedence of attack.

o Desired effects.o Most suitable ammunition.

o Most suitable method of engagement.

o Aiming points needed.

Issue complete fire order specifying any changesfrom the fire order standards.

Issue the battery fire order.

G-5

FM 6-40

c. Practice. Following pretraining, thesection must practice this drill to achieveinitial proficiency. After initial proficiencyhas been achieved, sustainment trainingevery 4 months is recommended. More

frequent training maybe necessary if the unit

has a high turnover of personnel, infrequentrelated training, loss of key personnel such aschief computer/computer, or unit-peculiarproblems that degrade drill proficiency.



(2) Time requ i rements . It isestimated that the battery FDC section crew

will require 4 hours of initial training and 1 to2 hours of sustainment training.

(3) Training area requirements.Each FDC section undergoing training willrequire a 50- by 50-meter area foremplacement of the section vehicle or for a

classroom of sufficient size to accommodatethe TOE equipment and the crew.


(a) All TOE personnel and equipment

are available and operational.



e. Training Procedures. To train thisdrill, the chief computer will have the FDCcrew occupy the training area. The chief

computer evaluates the actions of the sectionand notes all training deficiencies andomissions. An after-action review is given tothe FDC section upon completion of the drill.The drill is trained until no deficiencies arenoted by the chief computer.



FM 6-40

Table G-2. Attack targets drill (continued).

TASK

Chief Computer

Supervise target attack.

Computer

Issue fire commands tothe howitzer section.

Determine and an-nounce firing data.

FADAC/HHCOperator

Determine and an-nouce firing data.

HCO/VCO

Determine chart data.

Determine site.

RATELO

Transmit the message

CONDITIONS TRAINING/EVALUATION STANDARDS.. . .. .. . . ... * , m .... .. .

Fire order has been issued.

Fire order has been issued. Firecommand standards are posted.

Fire mission is in progress. Chartdata are announced.

Fire mission is in progress.


Computer requests site.


IaW 1

Direct and supervise personnel during fire missionprocessing.

Ensure the section computes firing data inaccordance with the fire order by use of the'appropriate source (BCS, FADAC, or manual).

Ensure fire commands are issued correctly.

Ensure firing data are computed correctly.

Ensure message to observer is sent correctly.

Ensure subsequent corrections are processedcorrectly.

Issue fire commands in the correct sequence.

Determine initial firing data for adjusting piece or

center platoon (FFE) within 30 seconds.

Announce fire commands.

Determine subsequent corrections to firing data,and announce subsequent fire commands/FFEcommands (include special corrections).

Determine and announce firing data to thecomputer.

Plot the target or subsequent corrections.

Determine and announce chart range.

Determine and announce chart deflection.

Measure and announce angle T if OT direction isgiven or if it changes.

Determine and announce site within 1 minute.

Determine and transmit the message to observer.

G-6



FM 6-40

*G-5, DETERMINE ANDAPPLYREGISTRATIONCORRECTIONS

a. General. This drill is an integralpart of the battalion training system and wasdeveloped from the ARTEP and soldier'smanuals. It trains ARTEP 6-100 subtask3-I-6-1d. It applies to all FADAC/manualunits.


(1) ARTEP subtask: 3-I-6-3a


061-280-1103061-280-1104

061-280-2003

061-280-2009

061-280-2702

061-281-1006

061-280-2004 061-281-1009061-280-2005 061-281-1104

061-280-2006 061-281-1702

061-280-2007 061-282-2006

(3) References:

ARTEP 6-100FM 6-13E1/2/3FM 6-30

c. Practice. Following pretraining, thesection must practice this drill to achieveinitial proficiency. After initial proficiencyhas been achieved, sustainment trainingevery 4 months is recommended. Morefrequent training may be necessary if he unit



(1) Personnel and equipment. Abattery FDC section TOE and a battery FD Csection crew are required to train this drill.

(2) Time requ i rements . It isestimated that the battery FDC section crewwill require 4 hours of initial training and 1 to2 hours of sustainment training.







(c) Unless otherwise specified in theconditions, no other competing actions areongoing, and weather conditions are

favorable.e. Training Procedures. To train this

drill, the chief computer will have the FDCcrew occupy the training area. The chiefcomputer evaluates the actions of the sectionand notes all training deficiencies andomissions. An after-action review is given tothe FDC section upon completion of the drill.The drill is trained until no deficiencies arenoted by the chief computer.

Table G-3. Determine and apply registration corrections drill.

TASK CONDITIONS TRAINING/EVALUATIONSTANDARDSir 1

The battery has registered.Adjusted data have beendetermined.

Manual-Determine GFT setting and deflectioncorrections within 2 minutes of receipt of adjusteddata and end of mission of the registration. SendGFT settings to battalion FDC (if applicable).

FADAC-Determine, record, and apply FADACresiduals within 4 minutes of receipt of adjusteddata.

G-7



FM 6-40

Table G-3. Determine and apply registration corrections drill (continued).

TASK

Chief Computer

Issue order to prepare/update GFT settings/computer residuals.

Verify the preparationof registration correc-tions.

CONDITIONS

Survey data not available at thetime of the registration are nowavailable.

The battery has registered.Adjusted data have beendetermined.

Registration corrections arebeing determined and applied.

TRAINING/EVALUATION STANDARDS-.-.-- II I

G-8

Determine multiplot GFT settings and deflectioncorrections within 2 minutes of applying FADACregistration residuals.

Send GFT settings/residuals to battalion FDC (ifapplicable).

HHC-Determine, record, and apply HHCregistration corrections within 4 minutes ofreceipt of the manual GFT setting.

Manual-Using survey data, determine new chartdata to the registration point.

Recompute site.

Determine new adjusted elevation and total

deflection correction.Determine new adjusted time if corrected VI isgreater than 100 meters.

Determine new GFT setting within 3 minutes ofreceipt of survey data.

FADAC-Enter survey data into FADAC.

Determine and apply new FADAC residuals.

Using FADAC, derive a new multiplot GFTsetting within 4 minutes of receiving surveydata.

HHC-Determine, record, and apply HH Cregistration corrections within 4 minutes ofreceipt of the manual GFT setting.

Direct and supervise personnel duringdetermination and application of registration. BCSresiduals should be determined and applied within2 minutes of receipt of adjusted data. FADAC andHHC registration residuals should be determinedwithin 4 minutes of receipt of adjusted data.

Organize the section beforehand to ensurerapid, accurate, and orderly computation.

Assign duties and ensure tasks are understood.Ensure section members are thoroughlyfamiliar with unit and section SOPs.

Ensure computer has correct adjusted data andis applying the data correctly in thecomputations.Ensure the FADAC and HHC operators have thecorrect adjusted data and are applying the datacorrectly. Assign ranges for multiplot GFTsettings.

'S



FM 6-40



Ensure GFT settings check at the met checkgage points; verify between GFTs.

Ensure GFT settings are prepared andtransmitted to battalion FDC (if applicable).

Computeir

Determine and apply A registration has been Determine and apply GFT setting without errorG FT set t ings and conducted. Adjusted firing data within 2 minutes of receipt of adjusted data.deflection correctionsto graphical equipment.

Determine a new GFTsetting when transfer-

ring from a map-spotfiring chart to a sur-veyed firing chart.

Determine total correc-tions from a registra-tion.

Determine a GFT set-

ting for a second-lot registration.

FADAC Operator

Using FADAC, com-pute, store, and trans-fer registration

and chart data are known.

Survey data not available at the

time of registration are nowavailable.

The battery has registered. TheGFT setting and initial chart datato the registration point areknown.

A second propellant lot has beenregistered with the first lot.Adjusted data and total fuzecorrection from the first-lotregistration, the site, and thechart range to the final pinlocation on the firing chart fromthe second-lot registration areknown.

FADAC is prepared for action.All known data are entered. Aregistration is being conducted.

Determine the GFT settings in the propersequence.

Determine the total deflection correction.

Determine the GFT deflection correction.

Applythe GFT setting to the GFT.

Announce the GFT setting to the GFT fan

operator.

Determine and apply new GFT setting and GFTdeflection correction without error within 3minutes of receipt of survey chart data to theregistration point.

Determine the new adjusted elevation.

Determine the new total deflection correction.

Determine the GFT deflection correction.

Apply the GFT settingto the GFT.

Announce the GFT setting to the GFT fan

operator.

Determine total corrections withouPerror within 3

minutes.

Determine total range correction.

Determine total deflection correction.

Determine total fuze correction.

Determine and apply the second-lot GFT setting

without error within 4 minutes.

Determine the adjusted deflection.

Determine the adjusted elevation.

Determine the adjusted time.

Determine the second GFT setting in the proper

sequence and apply it to the GFT.

Compute, store, and transfer registrationcorrections without error within 4 minutes ofreceipt of adjusted data.

G-9

TASK CONDITIONS



FI 6-40


TASK

corrections.

Derive adjusted data fora multiplotGFTsetting.

HHC Opelrator

Using the computer set,FA general, computeand store registrationcorrections.

Chavrt Operstor

Determine and an-nounce chart data.

Determinenounce site.

CONDITIONS

*11

Registration corrections arestored in FADAC. Ranges to twomet check gage points areannounced.

You have set up the HHC foraction. A GFT setting isannounced.

A registration is being con-ducted.

and an-Il The computer requests site.


Determine firing data for the adjustment of the

registration, and end the mission.Determine registration corrections.

Store registration corrections as directed, andtransfer corrections to nonregistering fire units.

Derive adjusted data for a multiplot GFT settingwithout error within 4 minutes.

Compute and store registration corrections

(residuals) without error within 4 minutes.

Determine and store range K.

Determine and store deflection correction.

Determine and store fuze K.

Determine and announce chart data for initial,

adjusting, and final corrections.

Determine and announce site as requested.

*G-6. ENETFALEZEIBCS FOBOPEIRATEON

a. General. This drill is an integralpart of the battalion training system and wasdeveloped from the ARTEP and soldier'smanuals. It trains ARTEP 6-100 subtask3-1-6-6. It applies to all BCS-equipped units.


(1) ARTEP subtask: 3-1-6-6

(2) References:

FM 6-1FM 6-50

FM 24-1FM 24-18TM 11-5985-357-13TM 11-7440-283-12-1STANAG 2867

c. Practice. Following pretraining, the

section must practice this drill to achieveinitial proficiency. After initial proficiencyhas been achieved, sustainment trainingevery 4 months is recommended. Morefrequent training may be necessary if the unithas a high turnover of personnel, infrequentrelated training, loss of key personnel such aschief computer/computer, or unit-peculiarproblems that degrade drill proficiency.

d. Recommended Training Support.(1) Personnel and equipment. A

G-1 011- 1 p- .I

-_j I --- - it



FM 6-40

battery FDC section TOE and a battery FDCsection crew are required to train this drill.

(2) Time requ i rements . It isestimated that the battery FDC section crewwill require 2 hours of initial training and 30minutes of sustainment training.






(c) Unless otherwise specified in theconditions, no other competing actions are

ongoing, and weather conditions arefavorable.

e. Training Procedures. To train thisdrill, the chief computer will have his FDCcrew occupy the training area.

(1) After the training area has beenoccupied, the chief computer will provide theXO's report and known battery, weapon, andmap data. The unit tactical mission and thecurrent met message are available. This taskshould be completed when occupation of theposition is completed. Char t /BCSverification and application of multiplot GFTsettings should be done without delay.

(2) The chief computer evaluates theactions of the section and notes all trainingdeficiencies and omissions. An after-actionreview is given to the FDC section aftercompletion of the drill. The drill is traineduntil no deficiencies are noted by the chiefcomputer.

Table G-4. Initialize BCS for operation drill.

TASK CONDITIONS TRAINING/EVALUATION STANDARDS

Chief Computer

Issue order to initializethe BCS. Perform chartchecks, and derivemultiplot GFT setting.

You will be given an operationalBCS and an adequate power

source.

Information required forinitialization is available. Chartsand graphical equipment areavailable.

Verify the initialization Fire direction center personnelprocedures. have completed initialization.

BCS Operator

Apply power to BCU.

Initialize BCS.

Use available power source.

Information required for

initialization is available. TheBCU is properly cabled, andradios are on proper fre-quencies.

Initialize BCS for operation.

Perform a chart check. Derive multiplot GFT

settings and apply to graphical equipment.

Announce the order to the section.

Recall selected initialization data/message, andspot-check for accuracy.

Ensure that chart checks with the BCS are withinstandards (±3 mils).

Ensure that the derived GFT setting is properly

applied to graphical equipment.

Operate from vehicle power/generator.

Correctly complete and execute the followingmessages:

BCS;INITBCS;SWITCHES

AFU;BAMOUPBCS;MVD

G-11



FM 6-40

Table G-4. Initialize BCS for operation drill (continued).

CONDITIONS TRAINING/EVALUATION STANDARDS

BCS;SBT FM;OBCO

SPRT;MAP SPRT;GEOMAFU;UPDATE MET;CMBCS;PIECESPerform chart check, and derive multiplot GF T

_settings.

*G-7. DETERMINEREPLOT DATA

a. General. This drill is an integralpart of the battalion training system and wasdeveloped from the ARTEP and soldier'smanuals. It trains ARTEP 6-100 subtask3-I-6-1g. It applies to all FADAC/manualunits.



(2) Individual soldier's manual tasks:061-280-1005 061-280-2013061-280-1006 061-281-1001

061-280-1100 061-281-1005

061-280-2012

(3) References:

ARTEP 6-100FM 6-13E1/2/3FM 6-30




(2) Time requirements . It isestimated that the battery FDC section crewwill require 2 hours of initial training and 30minutes of sustainment training.





(c) Unless otherwise specified in the

conditions, no other competing actions areongoing, and weather conditions arefavorable.


(1) After the training area has beenoccupied, the chief computer will provide theXO's report and known battery, weapon, andmap data. The unit tactical mission and thecurrent met message are available. This taskshould be completed when occupation of theposition is completed. Char t /BCSverification and application of multiplot GFTsettings should be done without delay.


G-12

TASK

S

S



FM 6-40

Table G-5. Determine replot data drill.


Chief Computer

Issue order to deter-mine replot data.

Verify the determina-tion of replot data.

Computer

Determine and an-nounce replot data(fuze quick or VT).

Determine and an-nounce replot data(fuze time).

FADAC Operator

Replot targets withFADAC.

HCO

Replot targets anddetermine and an-nounce grid location.

Compute and an-nounce successivesites.

The battery has fired a mission.

The observer has requestedRECORD AS TARGET, or theFDO has.directed that replot beperformed. Accurate targetlocation is required to allowfuture use of the target.

Replot is required on a targetthat has been fired.

Replot is being conducted.

Replot is directed. Successivesites are determined by the VCO.

Replot is directed.

Replot is directed.

Replot is directed.

Site is requested.

Obtain refinement data from the observer.

Determine replot grid and altitude.

Report replot grid to the FIST.

Direct and supervise the personnel duringdetermination and use of replot data.

Ensure the personnel are determining replot datacorrectly.

Determine and announce replot data without error

within 90 seconds.

Determine and announce initial replot range.

Determine and announce replot deflection.

Determine and announce final replot data.

Record replot location.

Determine and announce all replot data withouterror within 3 minutes.

Determine and announce the initial replot

range.

Determine and announce replot deflection.

Determine site.

Determine and announce final replot data.

Record replot location.

Determine initial firing data.

Determine fire-for-effect data.

Determine replot data.

Record replot data.

Replot targets without error within 8 minutes.

Polar plot the location of the target from thebattery center as directed.

Determine and announce eight-digitgrid coordinates of the polar plot location.

Tick mark and label in black.

Compute and announce site without error within 1minute.

G-13



Table G-5. Determine replot data drill (continued).

CONDUTOONS TRAi NNG/EVALUATION STANDARDS

Prepare and transmit Replot has been conducted. Transmit replot location to FIST.replot locationmessageto FIST.

*G-g, DETERINE ANDAPPLY METCORRECTIONS

a. General. This drill is an integralpart of the battalion training system and wasdeveloped from the ARTEP and soldier'smanuals. It trains ARTEP 6-100 subtask3-I-6-le. It applies to all FADAC/manualunits.




061-280-1700 061-281-1001061-280-1701 061-281-1009061-280-1703 061-281-1702061-280-2205 061-282-2206061-280-2206 061-282-2700061-280-2702 061-282-2701061-280-2704

(3) References:

ARTEP 6-100

FM 6-13E1/2/3c. Practice. Following pretraining, the

section must practice this drill to achieveinitial proficiency. After initial proficiencyhas been achieved, sustainment trainingevery 4 months is recommended. Morefrequent training may be necessary if the unithas a high turnover of personnel, infrequentrelated training, loss of key personnel such aschief computer/computer, or unit-peculiarproblems that degrade drill proficiency.


(1) Personne l and equipment . Abattery FDC section TOE and a battery FDCsection crew are required to train this drill.

(2) Time requirements . It isestimated that the battery FDC section crewwill require 6 hours of initial training and 2hours of sustainment training.







(1) When information becomesavailable, the chief computer will order hissection to derive met corrections and applythe corrections to graphical equipment.


G-114

FM 6-40

TASK

I



FM 6-40

Table G-6. Determine and apply met corrections drill.


Manual

Determine met correc A registration has beentions. conducted. Total corrections and

GFT settings have beendetermined. Ballistic andcomputer met messages currentat the time of the registration areavailable.

Position correct ions areavailable from a prior registra-tion. The tactical situationprecludes firing anotherregistration. Subsequentballistic and computer metmessages are received. Thebattery has not displaced.

A firing capability alongazimuths significantly differentfrom unit's primary azimuth offire is required.

Accuracy requirements an dtarget-engagement rangesnecessitate computation of amultiplot GFT setting.

Chief Computer

Order that position All information necessary toconstants be deter- compute the corrections ismined, available.

Determine position deflection correction, positionvelocity error, and position fuze correction.

Time: 12 minutes. Time starts upon receipt ofmet message and registration data.

Note. FADAC/HHC/BCS residuals may requiresubsequent recomputation if they were initiallycomputed by use of the last or standard met and amet is received later that was current at the time ofthe registration.

Manual/HHC

Update GFT setting and GFT correction.

Time: 11 minutes from receipt of met messagetocompletion of GFT setting and deflectioncorrections.

11 minutes for HHC.

FADAC/BCS

Input new met data.

Time: 5 minutes (manual)

1 minute (met tape-FADAC only)

ManualDetermine a valid GFT setting for each 800-milsegment of unit's area of responsibility by use ofthe eight-direction met technique within 45minutes.

FADAC

Derive GFT settings for applicable octants.

Note. For RAP missions, apply propellanttemperature range correction (manual, FADAC,and HHC).

Determine second and third multiplot GFT settingsby use of the met to a met check gage pointtechnique.

Select met check gage points that are farthest (inrange) from the registration point.

Announce order to the section.

G-15



FM 6-40

Table G-6. Determine and apply met corrections drill (continued).

TASK

Spot-check data.

Order GFT settings becomputed to selectedoctants.

Order firing data to becomputed to a targetoutside the transferlimits of currentlycomputed GFT settings.

Computer

Determine positioncorrections.

Determine GFT settingfor a 6,400-mil met.

Update the GFT setting.

Compute data to atarget outside transferlimits.

CONDITIONSir ii

Fire direction center personnelhave completed determiningposition constants.

Octants are identified, and metcheck gage point ranges arebased on the tactical situation.

A target is received outsidetransfer limits. Current met dataand position constants/residuals are applied.

A current met message and

registration data are available.

Met data have been identified,and position constants areavailable.

New met data have beenidentified.

Current met data and positionconstants are available. The fireorder has been issued identify-ing charge, ammunition, andpropellant lot. Chart data havebeen determined.


Spot-check for the following:o Use of proper TFT.

O Math errors.

o Use of proper met line.

FADAC

o Entry'of met message into FADAC.

o Input of proper adjusted data whendetermining residuals.

o Application of residuals to the FADAC andrecord of residuals in the FADAC logbook.



Manual

Determine position deflection correction.

Determine position VE.

Determine position fuze correction.

Manual-shell HE, DPICM, RAP

Dioc

M

etermine multiplot GFT settings for required

:tants.

lanual-shell HE, DPICM, RAP

Determine a new adjusted elevation for amultiplot GFT setting.

Determine a new adjusted time for a multiplotGFT setting.

Determine new total and GFT deflectioncorrections for a multiplot GFT setting.

Apply the multiplot GFT setting.

Determine the quadrant to fire.

Determine the time to fire.

Determine the deflection to fire.

G-16



FM 6-40

Table G-6. Determine and apply met corrections drill (continued).

CONDITIONS

Current met data are applied tothe FADAC.

Derive a GFT setting for Current met data and residualsa 6,400-mil met. are applied to the FADAC.

Update theGFTsetting. New met data have beenidentified.

Determine positioncorrections.

Determine a GFT set-ting for a 6,400-milmet.

Update the GFT setting.

A current met message andregistration data are available.

Met data have been identified,and position constants areavailable.

New met data have beenidentified.


NCO (FADAC Oper-

ateor)Determine residuals.

*G-9. ESTABLESH AND

MAENTAENCOMMUNWCAT[ONS

a. General. This drill is an integralpart of the battalion training system and wasdeveloped from the ARTEP and soldier'smanuals. It trains ARTEP 6-100 subtasks3-I-6-1a and 3-I-6-6a. It applies to all units.

b. Prerequisites. Certain crew drills,ARTEP tasks, and individual skills must bemastered before this drill can be trained. Thepretraining requirements include the

following:(1) FM 6-50, chapter 10.


061-280-1006 113-587-3077

061-280-3000 113-596-1068

113-573-4003 113-600-1015

113-573-7017 113-622-1066113-573-8006 113-622-2004

113-587-2043 113-622-2005

(3) References:FM 6-30FM 6-50FM 21-2FM 24-1FM 24-18STANAG 2867

TM 11-5820-401-10-1TM 11-5820-401-10-2TM 11-5820-477-12

TM 11-5830-340-12

TM 11-5985-357-13TM 38-750


G-17

TASK

Determine and apply FADAC residuals.

Determine multiplot GFT settings for shell HE,DPICM, and RAP.

Input new met data.

Derive multiplot GFT settings for shell HE, DPICM,

and RAP.

Determine position deflection correction.

Determine position VE.

Determine position fuzecorrection.

Shell HE, DPICM, and RAP

Determine multiplot GFT settings for requiredoctants.

Shell HE, DPICM, and RAP

Determine multiplot GFT settings for requiredoctants.

I1



FM 6-40



(2) Timer equ i rements . It isestimated that the battery FDC section crew

will require 2 hours of initial training and 30minutes of sustainment training.






e. Training Procedures. To train thisdrill, the chief computer will have his FD Ccrew occupy the training area.

(1) Immediately upon occupation of thetraining area, the chief computer will directthe section to establish radio and wirecommunications. To be proficieint at thistask, the section must be trained to maintaincommunications in all types of weather, onany terrain, and under electronic warfareconditions. This drill must be maintainedcontinuously during all training andoperational conditions. The chief computerwill provide pertinent CEOI and operationsorder information. Time and drill sequencewill'begin when the section has occupied theposition/training area. The maintenancephase of the drill will follow theestablishment phase.


Table G-7. Establish and maintain communications drill.

TASK CONDITIONS TRAI NING/EVALUATION STANDARDSIn t lTMra iAeadsc rSa ioq imnt

Chief Computer.

Issue the order toestablish and maintaincommunications.

G-18

The battery is conducting eithermiddle- or high- intensitycombat operations (simulated).

The FDC section and equipmentare in position.

Install FM~radio set, and secure radio eq uipment tofacilitate best transmission/reception.

Use antenna group RC-292/OE-254 correctly.

Use remote radio setting.

Enter external radio nets as directed.

Establish/maintain wire communications withthe howitzer sections, battery operations center,and field storage location (if applicable).

Direct the personnel during occupation of theposition to establish and maintain FDCcommunications. Communications should beestablished with a high priority.


Assign duties and ensure that tasks areunderstood.

Assign section priorities for establishing theposition.



FM 6-40

Table G-7. Establish and maintain communications drill (continued).

TASK

I1

TIaiai

CONDITIONS

he FDC section and equipmentre in position. Communicationsre being established.

Verify the establish-ment and maintenanceof communications.

Use FDC procedures toreceive the firingbattery and enemytransmissions.

RATELO

Prepare/operate FMradio sets.

Install and operate afield telephone.

Install radio set controlgroup AN/GRA-39.

Operate radio se tcontrol group AN/GRA-39.

Install antenna groupOE-254/GRC.

I

[1rRAINING/EVALUATION STANDARDS

Ensure section members are thoroughlyfamiliar with unit and section SOPs.

Ensure the RATELO and other section membershave the correct communications operating data.

Ensure the FDC has entered all radio nets properly.

Ensure the FDC has installed all communicationsequipment correctly.

Ensure all required wire nets are operational.

Use procedures that hinder the capability of

enemy targeting agencies in detecting andlocating field artillery positions.

Ensure that communications security proceduresare rapidly followed by all radio or telephone

operators operating in fire direction nets or FDCwire communications.

Install batteries in the AN/GRA-39.

Install control units on site.

Install field wire between the sites.

Update DA Form 2404.

Note. To dismount the set, reverse theprocedures. Observe all applicable warnings.

The section is in a middle- orhigh-intensity combat environ-ment (simulated).

You have all required equipmentand forms.

You have properly installed theAN/GRA-39. You have an

operational FM radio, anotherradio station with which tocommunicate, a CEOI extract,and an operator/attendant for

the radiosite.

You have an antenna groupOE-254/GRC, a designated sitefor installation, two assistants,and a supervisor.

Note. Starting procedures and communicationschecks must be performed within 10 minutes.

WARNING: If you must erect theselong-range antennas near power lines,power-line poles, towers, or buildings with

overhead power line connections, never put the

antenna closer than twice the antenna height

from the base of the power line, pole, tower, or

buildings. Do not erect the antenna during apower storm ..... ... .

G-19

I

I

.

I

Perform starting procedures.

Conduct telephone communications checkbetween local and remote control units.

Conduct radio transmission and reception check.

Conductstopping procedures (when required).

Taa

Note .Statingprocdure a n d c o m u i c a t i o n

I

I

0

0

m

I

0

0

0

m



Table G-7. Establish and maintain communications drill (continued).

TASK CON D I T I O N S T R A I N I G/EVALUATiON STADARDS

Evaluate the installation site.

Lay out the installation site.

You will have a vehicle with anAN/VIC-1 installed; FM radiosets mounted, connected, andoperational; and a CEOI extract.

You will be given all requiredequipment, materials, andforms.

You are operating an FM radiowithin a net. An interferingsignal of undesignated originoccurs. You have a CEOI extract,a pencil, paper, a compass or amap, and a watch or othertime-determining source.

You will be given anobserver'scall for fire, the fire order, and

the fire order standards.

Encode and decode You will be given a CEOI extract Encode and decode a message within 30 secondsmessages using KTC With KTC 600. per code or word/phrase.600 tactical operationscode (OPCODE). Observe security precautions.

FM 6-40

G-20

ii

Operate intercom-munications systemAN/VIC-1 with FMradios (tracked vehicles

only).

Perform preventivemaintenance checksand services (PMCS) oncommunicationsequipment.

Use an automatedCEOI.

Prepare/submit oper-tor's meaconing, intru-sion, jamming, inter-ference (MIJI) report.

Prepare and transmitmessages to observers.

Assemble the antenna.

Erect the antenna.

Connect the antenna.

Mote. The antenna must be properly installedwithin 20 minutes.

Observe all warnings and cautions.

Set intercom switches and controls.

Connect audio accessories.Operate the radio intercom system

Perform routine checks.

Perform operator's daily PMCS.

Perform operator's weekly PMCS (asnecessary).

Perform operator's monthly PMCS (asnecessary).

Wote. Perform all PMCSwithin 20 minutes (30minutes if the installation includes an intercom

system).

Submit the report to the net control station (NCS).

Prepare the initial MIJI report.

Submit the initial MIJI report.

Assemble additional information for the follow-upMIJI report.

Transmit the message to observer in sequence.Transmit angle T (if necessary).

Transmit probable error in range (if necessary).

Transmit time of flight (if necessary).



FM 6-40

.*G-10. PREPARE FORDEDICATED BATTERYOPERATIONS

a. General. This drill is an integral

part ofthe battalion training system and was

developed from the ARTEP and soldier'smanuals. It trains ARTEP 6-100 subtasks3-1-6-1f and 3-I-6-6d. It applies to all105-mm and 155-mm units.



(2) Individual soldier's manualtasks:

061-280-1001

061-280-2019

(3) References:ARTEP 6-100FM 6-13E1/2/3FM 6-20

c. Practice. Following pretraining, thesection must practice this drill to achieveinitial proficiency. After initial proficiency

has been achieved, sustainment trainingevery 4 months is recommended. Morefrequent training may be necessary if the unithas a high turnover of personnel, infrequentrelated training, loss of key personnel such aschief computer/computer, or unit-peculiarproblems that degrade drill proficiency.



(2) Time requ i rements . It isestimated that the battery FDC section crew


(3) Tra in ing area requ i rements .Each FDC section undergoing training will

require a 50- by 50-meter area foremplacement of the section vehicle or for aclassroom of sufficient size to accommodatethe TOE equipment and the crew.






favorable.

e. Training Procedures. To train thisdrill, the chief computer will have his FD Ccrew occupy the training area.

(1) During normal operations in thearea, the chief computer will inform thesection that the battery will be dedicated to acompany/team maneuver force in amovement to contact and that preparationsto assume this role must be accomplished. Tobe proficient at this task, the section should

be trained to react to hasty transition todedication and deliberate transition to

dedication. This drill should be accomplishedduring operations in an area and upon receiptof a properly authenticated order fordedication. The chief computer will providethe section crew.

(2) The chief computer evaluates theactions of the section and notes all trainingdeficiencies and omissions. An after-actionreview is given to the FDC section aftercompletion of the drill. The drill is trained

until no deficiencies are noted by the chiefcomputer.

Table G-8. Prepare for dedicated battey operations drill.

TASK CONDITIONS TRAINING/ EVALUATION STANDARDS

G-21

F The battery has been given a IPost maneuver force scheme of maneuver ondedicated role to support aIsituation map.



FM 6-40

Table G-8. Prepare for dedicated battery operations drill (continued).

TASK I CONDITIONS flTRAINING/EVALUATION STANDARDS

company/team in a movement Plot control measures and checkpoints on theto contact. firing chart in blue.

Receive the fire support plan.

Mote. The deliberate fire support plan isreceived from battalion FDC/squadron firesupport section. The hasty fire support plan isreceived by the battery FDC from the FIST (usuallyless than 5 minutes before dedication).

Obtain maneuver call signs and frequencies.Monitor maneuver company/team command net.

Process planned targets. Plot and compute firingdata for all planned targets and checkpoints. Senddata for suppressive targets to howitzer section.

Chief Computer

Issue order to prepare The section is to prepare forfor battery operations. dedicated battery operations.

Plot control measuresand checkpoints onfiring charts.

Plot targets and deter-mine and announcechart data.

VCo

Post maneuver forcescheme of maneuveron the situation map.

Computer

Process plannedtargets.

Fire support plan has beenreceived.

Fire supportreceived.

Fire supportreceived.

plan has been

plan has been

[Note. Priority targets are assigned one per firingplatoon.

Direct and supervise the personnel duringpreparation.

Organize the section beforehand to ensure rapidand proper preparation.


Ensure section members are thoroughly familiar

with unit and section SOPs.

Plot checkpoints in blue.

Include planned targets and checkpoints.

Mark grid north for each target checkpoint for usewith the target grid.

Input data in computer files.

Use themost

currentinformation. Update as newinformation is received.

Compute firing data for all planned targets andcheckpoints.

Send data for suppressive targets to howitzersections, one priority target per firing platoon.

Update firing data as required.

G-22



FM 6-40

Table G-8. Prepare for dedicated battery operations drill (continued).


*G-11. MANAGE ANDAPPLY MUZZLEVELOC I TYINFORMATION

a. General. This drill is an integralpart of the battalion training system and was

developed fromthe ARTEP and soldier's

manuals. It trains ARTEP 6-100 subtasks3-1-6-1 and 3-1-6-6. It applies to all units.


(1) Individual soldier's manual task:

061-380-3910

(2) References:

FM 6-1FM 6-50TM 11-7440-240-10TM 11-7440-283-12-1MCTV-90-1




(2) Time requ i rements . It isestimated that the battery FDC section crewwill require 2 hours of initial training and 30minutes of sustainment training.







favorable.


(1) The chief computer will provide thenecessary blank forms and MV data. He willthen direct the section to determine updatedMVV data, record the data, and prepare avelocimeter rotation schedule for upcomingfiring. The drill sequence will begin whendirected. The section should be trained to

update MVV data when a new lot ofpropellant is being fired and when a set ofcalibration data has been determined for thefire unit.


G-23



FM 6-40

Table G-9. Manage and apply muzzle velocity information.drill.

TASK CONDITIONS TRAINING/EV ,LUATION STAmbARDS

The battery has completed Determine and apply MW data for all weapons inmeasuring a set of calibration the unit.data by use of the M90velocimeter. Record the data in the unit ballistic computer.

IUpdate the unit MV logbook.

Chief Computer

Issue the order todetermine updatedMVV data for the unit

and apply the informa-tion.

Determine MVV data.

The FDC section has just beendirected by the FDO to updateMVV data on the basis of.a new

set of M90 velocimetermeasurements.

You receive an M90 velocimeterrecord from the firing battery.

Schedule the rotation of the M90 velocimeter.

This drill should be accomplished within 30minutes of receipt of a complete set of'M90velocimeter measurements from the firing battery.

Direct and supervise the personnel during MV Vupdate. MW data should be updated and recordedas soon as possible.

Organize the section beforehand to ensure rapidand accurate computation.



Average the powder temperatures.

Determine the usable rounds.

Determine the MW data.

Record MW data in the MV logbook.

Direct MVV data be entered in ballistic computersor on manual met forms.

Determine muzzle velocities.

Announce muzzle velocities to the XO.____________________________ i ____________________________________________

*G-12. ]INI[TIALIZETHE HAND-HELDCALCULATOR FOROPERATION

a. General. This drill is an integralpart of the battalion training system and wasdeveloped from the ARTEP and soldier'smanuals. It trains ARTEP 6-100 subtask3-1-6-1. It applies to all units.

b. Prerequisites. Certain crew drills,ARTEP tasks, and individual skills must bemastered before this drill can be trained. The

pretraining requirements include thefollowing:


(2) Individual soldier's manual tasks:061-282-2000061-282-2001

061-282-2006

(3) References:ARTEP 6-100FM 6-13E1/2/3

G-24



FM 6-40

c. Practice. Following pretraining, thesection must practice this drill to achieve

.initial proficiency. After initial proficiencyhas been achieved, sustainment trainingevery 4 months is recommended. Morefrequent training may be necessary if the unit




(2) Time requ i rements . It is

estimated that the batteryFDC section crew








(1) After the training area has beenoccupied, the chief computer will provide theXO's report and known battery, weapon, andmap data for a registration or a derived GFTsetting.

(2) The chief computer evaluates thatactions of the section and notes all trainingdeficiencies and omissions. An after-actionreview is given to the FDC section aftercompletion of the drill. The drill is traineduntil no deficiencies are noted by the chiefcomputer.

Table G-I0. Initialize the hand-held calculator for operation drill.


Chief Computer

Issue order to initializethe HHC for operation.

You will be given an operationalHHC and an adequate powersupply.

Information required forinitialization is available.

Verify the initialization Fire direction center personnelprocess. have completed initialization.

HHC Operator

Prepare the HHC for You have been given anoperation. operational HHC.

Initialize the HHC for operation.

Perform a chart check, and check firing data to atarget.

Recall selected initialization information, and spotcheck for accuracy.

Ensure that the range (±30 meters) and azimuth

check with the chart within standards (+3 mils).

Ensure that firing data computed to a target withthe HHC are compatable with the BCS.

Perform steps to prepare for action.

Perform program setup.

G-25



FM 6-40

Table G-1 0. Initialize the hand-held calculator for operation drill (continued).

TRAINING/EVALUATION

*G-13. JNETEALEZE FADACFOR OPERATEON

a. General. This drill is an integralpart of the battalion training system and wasdeveloped from the ARTEP and soldier'smanuals. It trains ARTEP 6-100 subtask3-1-6-1c. It applies to all FADAC 105-mm,155-mm, and 203-mm units.


(1) FM 6-50, chapter 6.

(2) Individual soldier's manual tasks:061-281-1000 061-281-1013

061-281-1001 061-281-1104061-281-1012

(3) References:

ARTEP 6-100FM 6-13E1/2/3TM 5-2805-203-14

TM 5-6115-271-14TM 9-1220-221-10

TM 9-1220-221-10-1

TM 38-750


G-26



(2) Time requirements . It isestimated that the battery FDC section crewwill require 2 hours of initial training and 30minutes of sustainment training.






e. Training Procedures. To train thisdrill, the chief computer will have his FDCsection crew occupy the training area.

(1) While the section is occupying thetraining area, the chief computer will providethe XO's report, the azimuth of fire, and thebattery grid locations. The unit tacticalmission is known. The chief computer willprovide the HCO with known battery,weapon, and map data and a current metmessage. This task should be accomplishedimmediately upon occupation of the position.Chart/FADAC verification and applicationof mulitplot GFT settings should be donewithout delay.

. . " . . % - L L k A . lk11- & . " && I it I- i &UiWIJkALLALAuklaam I-A



FM 6-40

(2) The chief computer evaluates the

actions of the section and notes all training

deficiencies and omissions. An after-action

review is given to the FDC section aftercompletion of the drill. The drill is traineduntil no deficiencies are noted by the chiefcomputer.

Table G-1 1. Initialize FADAC for operation drill.


The FADAC is operational, andknown battery, weapon, andmap data have been received. Acurrent computer met messageis available.

Perform program tests, and set up and enterknown data into FADAC.

Note. This task should be accomplishedimmediately upon occupation of the position an dcompletion of chart verification. Th ecomputer VCO should apply the multiplot GFTsetting to the GFT/GFT fan.

Chief Computer

Issue order to initialize The FDC section and equipment Direct the personnel during occupation of the

FADAC for operation. are in position. position to establish and maintain the FDC.

Verify the initializationof FADAC for operation.

HCO (FADAC

Operator)

Operate a generator set(FADAC).

Prepare the FADAC foroperation.

The FADAC is being initialized.

You have been given anoperational FADAC and agenerator.

You have been given a FADAC, aFADAC table, a generator, andrequired power cables.



Assign section priorities for establishing theposition.


Ensure the HCO and other section members havethe correct known data.

Ensure program tests, and setup are performedcorrectly, and ensure known data are entered intoFADAC.

Ensure chart/FADAC checks are performed andthat checks are within tolerance.

Ensure the multiplot GFT setting is derivedproperly and is placed on the GFT/GFT fan.

Prepare the generator set for starting.

Place the generator set under load, and makeadjustments as necessary.

Stop the generator engine (when required).

Start the generator set.

Perform program tests 1 through 3.

Set up each fire unit.

G-27



FM 6-40

Table G-1 1. Initialize FADAC for operation drill (continued).

TASK

Enter known data intoFADAC.

Derive a multiplot GFTsetting by use ofFADAC.

Service the generatorset (FADAC).

CONDITIONS TRAINING/EVALUATION STANDARDSB. _________________________________________________ i ______________________________________________________________________________11. ~1t Enter known data without error within 10

You have set up the FADAC andhave known data.

You have prepared the FADACfor operation. You

are giventhree met check gage points fora propelling charge.

You have been given a gener-ator set, required manuals andforms, and pencil and paper.

Enter known data without error within 10minutes.

Enter battery data.

Enter weapon and ammunition data.

Enter map/area data.

Enter met message.

Enter and store observers' locations.

Enter and store target, known point, andregistration point information.

Derive the multiplot GFT setting without error

within 4 minutes.

Perform PMCS on the generator set.

Perform PMCS on the generator engine.

Enter data on DA Form 2404.

*G-14. DETERMIMNESPECIAL

CORRECTIONSa. Genera l . This drill is an integral

part of the battalion training system and wasdeveloped from the ARTEP and soldier'smanuals. It trains ARTEP 6-100 subtask3-I-6-3j. It applies to all FADAC/manualunits.

b. Prerequis i tes . Certain crew drills,ARTEP tasks, and individual skills must bemastered before this drill can be trained. Thepretraining requirements include thefollowing:


061-280-2800061-280-2801

(2) References:

ARTEP 6-100FM 6-13E1/2/3

c. Prac t ice . Following pretraining, thesection must practice this drill to achieve

initial proficiency. After initial proficiencyhas been achieved, sustainment trainingevery 4 months is recommended. Morefrequent training may be necessary if the unithas a high turnover of personnel, infrequentrelated training, loss of key personnel such aschief computer/computer, or unit-peculiarproblems that degrade drill proficiency.


(1) Personne l and equipment . Abattery FDC section TOE and a battery FDCsection crew are required to train this drill.

(2) Time r e q u i r e m e n t s . It isestimated that the battery FDC section crewwill require 2 hours of initial training and 30minutes of sustainment training.

(3) Tra in ing area requirements .Each FDC section undergoing training willrequire a 50- by 50-meter area foremplacement of the section vehicle or for aclassroom of sufficient size to accommodatethe TOE equipment and the crew.


G-28

11 1



(a) All TOE personnel and equipmentavailable and operational.

(b) All personnel are MOS-qualified.(c) Unless otherwise specified in the

ditions,. no other competing actions aregoing, and weather conditions areorable.

e. Training Procedures. To train thisll, the chief computer will have his FDC

crew occupy the training area. After thetraining area has been occupied, the chiefcomputer will provide the XO's reportcontaining piece displacement and platoonMVV data. The chief computer evaluates theactions of the section and notes all trainingdeficiencies and omissions. An after-actionreview is given to the FDC section aftercompletion of the drill. The drill is traineduntil no deficiencies are noted by the chiefcomputer.

Table G-1 2. Determine special corrections drill.

TASK] CONDITIONS TRAINING/EVALUATION STANDARDS

hief Computer

sue the order to applyliberate specialrrections to a fire-r-effect mission.

sue the order to applyasty special correc-ns to an adjust fireission.

omputer

etermine deliberateecial corrections, andnounce them to eachatoon.

etermine hasty spe-

orrections, andce them to each

Upon receipt and computation ofa call for fire, the FDC appliesspecial corrections (FFEmission) or hasty corrections(adjust fire mission) by use ofdeliberate or hasty specialcorrections to the fire-for-effectdata.

The FDC has received afire-for-effect mission. Th eradius of the target is 100meters or less.

The FDC has received an adjustfire mission. The radius of targetis 100 meters or less.

You will be given a completedrecord of fire with initial firingdata, a prepared M10/M17plotting board, and MV data foreach platoon.

You will be given a completedrecord of fire with initial firingdata, fire-for-effect data,platoon displacement data, andMV data for each platoon.

The FDC will apply special or hasty corrections tothe firing data.

Announce the order to the fire direction center.

Announce the order to the fire direction center.

Compute deflection, quadrant, and time correctionvalues.

Apply correction values to initial firing data todetermine each platoon's firing data.

Announce special corrections to each platoon.

Compute deflection, quadrant, nd time correctionvalues.

Apply correction values to fire-for-effect data foreach platoon.

I I Announce special corrections to each platoon.

FM 6-40



FM 6-40

APPENDIX H

TARGET ANALYSIS ANDMUNITIONS EFFECTS

H-1. PURPOSEBattalion and battery FDOs are

responsible for supervising all operationswithin the fire direction center. The first stepin processing any fire mission received in theFDC is issuing the FDO's fire order. The fireorder is based on the call for fire and theFDO's assessment of the target. The fireorder specifies a method of attack that willplace a desired effect on the target. This

appendix discusses the decision procedures,publications, and equipment used by theFDO to analyze and attack a target properly.

H-2. TARGET ANALYSIS

a. Target analysis is the examination of apotential surface target to determine the mostsuitable attack weapon/ammunition and themost suitable method of attacking a target.

b. All targets should be analyzed as theyare received in the FDC and fire planning

action initiated. The analysis of a target isvalid only for the level at which it wasperformed. For example, a battalion FDOmight consider an automatic weapon aninsignificant threat to the brigade mission.However, the same weapon may be of criticalimportance to the battery FDO of a dedicatedbattery supporting a maneuver platoon incontact.

c. The amount of time devoted to targetanalysis and the thoroughness of theanalysis depends on the following:

(1) Amount of target information.(2) Availability of weapons to attack

the target.(3) Urgency of the engagement.

H-3. DETERMINING THEPRECEDENCE OFATTACK

a. General. When an FDO receives afire mission, he has the following options:

(1) Attack the target immediately.(2) Defer attacking the target until an

existing fire mission is complete.(3) Pass the fire mission to another fire

direction center.

(4) Cancel the mission. An FDO selectsa particular precedence of attack afterconsidering the following:

(a) Target characteristics.(b) Target location.(c) Terrain.(d) Weather.(e) Commander's criteria.

b. Target Characteristics.

(1) Targets encountered on th ebattlefield vary considerably in composition,degree of protection, shape, mobility, andrecuperability. To simplify the comparison ofeffectiveness of particular weapons androunds, targets have been divided into four

categories(table H-i). Examples are listed in

each category. Under certain conditions,

Table H-1. Categories of targets.

CATEGORY EXAMPLE

Area (personnel) SquadPlatoonBatteryCompany

Small (personnel)Observation postSmall patrolCommand post

Small (materiel) Tank(point) Armored personnel

carrierBunker, machine gun

Area (materiel) Armored formationTruck parkAmmunition dump

H-1



FM 6-40

some examples could be listed in more thanone category. For example, a motorized riflebattalion could be both a first category and afourth category target.

(2) For personnel targets in particular,the posture of the target is extremelyimportant. Normally, target postures used forpersonnel targets are standing, prone, and infoxholes. For computation, it is assumed thatthe personnel are wearing helmets and thatpersonnel in foxholes are in a crouchingposition. In describing a target's posture,consideration must be given to the protectionafforded by the terrain. For example, aninfantry platoon may be attacking in astanding posture. However, irregular terrainmay provide protection equivalent to theprone position. Usually, personnel targetswill seek a more protective posture during anengagement; for example, from a standing toa prone position. This change is calledposture sequencing. Posture sequencingcauses considerable degradation of effects asadditional volleys are fired and is the reasonfor the continual emphasis on surprise ormass fires. For the purpose of analysis,personnel targets in the offense areconsidered to be one half standing and onehalf prone during the first volley of fire andall prone for subsequent volleys. In adefensive configuration, personnel targetsare considered to be one half prone and on ehalf in foxholes during the initial volley andall in foxholes for subsequent volleys.

(3) A target must be analyzed todetermine its weak points. Where the target ismost vulnerable and what fires will bestexploit its weaknesses are influenced by thedegree of damage desired. Often there is atendency to overkill the target when lesscombat power would suffice. On the basis ofthe commander's criteria, the FDO must

ascertain the degree of effects needed(destruction/neutralization/suppression) tosupport the tactical plan (fig H-i). Theacceptable degree of damage is that level thatyields a significant military advantage. Forexample, fire from a heavily protectedmachine gun emplacement may be silencedby obscura t ion th rough smoke andsubsequent engagement by direct fire asopposed to the expenditure of an excessivenumber of HE rounds required fordestruction.

c. Target Location. The proximity ofthe target to friendly troops and the accuracyof the target location must be weighed. Theimportance of certain targets that are notaccurately located may justify the fire ofseveral units to ensure coverage. Close-indirect support fire requirements may dictatethe use of a specific caliber of weapon.

d. Terrain. The terrain in the targetarea has a direct effect on the vulnerability ofthe target. Rugged terrain affordsconsiderable natural cover and makes targetlocation difficult. Certain terrain providescomplete protection from some angles ofapproach but not others, thus influencing theunit and munitions to be employed. Thenature of the vegetation in the target areashould be considered in the selection ofammunition.

e. Weather. Weather is of littleconsequence when evaluating a target to beattacked with high-explosive/quick.However, precipitation and wind are ofparticular importance in evaluating a targetto be attacked with ICM, smoke, or FASCAMor when using illumination projectiles. Lowclouds, thick fog, surface water, and raindegrade the effectiveness of VT fuzeM513/M514.

f. Commander's Criteria. All phasesof target analysis are conducted withinconstraints established by the commander.In determining the precedence for attacking atarget, primary consideration should begiven to the commander's target priorities.On the basis of ammunition constraints, acommander will also specify the type effectshe desires to be attained against specifictarget categories. The three target effectscategories are discussed below.

(1) Suppression. Suppression of atarget limits the ability

ofenemy personnel

toperform their mission. Firing HE/VT reducesthe combat effectiveness of personnel andarmored targets by creating apprehension orsurprise and causing tanks to button up .Smoke is used to blind or confuse. The effectof suppressive fires usually lasts only so longas the fires are continued. This type fire isused against likely, suspect, or inaccuratelylocated enemy firing units. It can be deliveredby small delivery units or means and requireslittle ammunition.

H-2



FM 6-40

TARGETCHARACTERISTICS TARGET LOCATION

LOCATION ERRORPROXIMITY TO

FRIENDLY TROOPS

COMPOSITION

SIZE/SHAPE

VULNERABILITY

MOBILITY

RECUPERABILITY

TERRAIN/WEATHER

PROTECTION AFFORDEDBY TERRAIN

DELIVERY CONSIDERATIONS

EFFECTS DEGRADATION

COMMANDER'S CRITERIAAMMUNITION CONSTRAINTS

DESIRED EFFECTS

TARGET PRIORITY

PRECEDENCE OF ATTACK DECISION

1. ATTACK IMMEDIATELY

2. DEFER FIRING UNTIL ONGOING MISSION ISCOMPLETE

3. PASS TO OTHER FIRING UNIT

4. CANCEL MISSION

Figure H-1. Determining the precedence of attack.

H-3



FM 6-40

(2) Neutralization. Neutralization ofa target knocks the target out of the battletemporarily. Ten percent or more casualtieswill neutralize a unit. The unit will becomeeffective again when the casualties arereplaced and damage is repaired.

Neutralization fires are delivered againsttargets located by accurate map inspection,by indirect fire adjustment, or by a targetacquisition device. The assets required toneutralize a target vary according to the typeand size of the target and the weapon/ammunition combination used.

(3) Destruction. Destruction putsthe target out of action permanently. Thirtypercent casualties or materiel damageinflicted during a short time span normallyrenders a unit permanently ineffective.Direct hits are required

to destroy hardmateriel targets. Targets must be located byaccurate map inspection, by indirect fireadjustment, or by a target acquisition device.Destruction usually requires a large amountof ammunition from many units. Destructionof armored or dug-in targets with artilleryweapons is not economical.

H-4. DETERMINING THEMOST SUITABLE

AMMUNITIONWhen an FDO decides to attack a target. hemust select a weapon/ammunit ion

combination that can achieve a desired effect

with a minimum expenditure of availableammunition stocks. Figure H-2 depictsweapon/ammunition selection.

a. Munitions.

(1) Ammunition type and quantity.The nature of the target and its surroundingsand the desired effects dictate the type andamount of ammunition to be used. For adetailed discussion of ammunition and fuzes,refer to FM 6-141-1 and FM 6-141-2. Theammunition resupply system may sometimesrule out the best ammunition selection. Forexample, extensive smoke fires may beneeded to screen maneuver movement, butsuch fires would probably cause a resupplyproblem. Some types of fires require moreammunition than others. Suppression andneutralization fires usually use lessammunition than destruction fires.

(2) Troop safety. Troop safety is amajor concern when considering theweapon/ammunition selection for firingclose-in targets. The FDO must ensure thatfires do not endanger troops, equipment, andfacilities.

(3) Residual effects in target area.Residual effects from special ammunitionwill influence the occupation of an area, andFASCAM munitions may alter the directionof movement of supported elements.Conditions may be hazardous for supportedtroops occupying an area immediatelyfollowing attack by certain munitions.Weather changes may alter choices of certain

H-4

__TARE

MUNITIONS W E A O N r

TYPE AND QUANTITY AVAILABLE CALIBER AND TYPETROOP SAFETY SYSTEM RESPONSE TIMERESIDUAL EFFECTS PREDICTED FIRE CAPABILITYEFFECTIVENESSDISPERSION

MOST SUITABLE WEAPON/AM MUNITION

Figure H-2. Weapon/ammunition selection



FM 6-40

a. Aiming Points. Normally, the sizeof the area to be attacked is determined by thesize of the target or the size of the area inwhich the target is known to be located orsuspected to be located. A single aiming pointlocated on the center of the target is used toattack small targets. When attacking largetargets, multiple aiming points must bedesignated to distribute the fires and insureadequate coverage. Chapter 13 givesprocedures for establishing multiple aimingpoints.

b. Density and Duration of Fires.Intense fires of short duration generallyproduce the best target effect. However, thetactical situation may require fires to becontinued over a long period of time. Someexamples are harrassing and interdiction

fires during darkness, screening smoke fires,continuous illumination fires, andsuppressive fires supporting a maneuverfinal assault on an objective.

H-6. PREDICTING WEAPONSEFFECTS

The most important step in performing atarget analysis is determining the numberand type of rounds required to produce adesired effect on a target. The battalion orbattery FDO determines attack data byreferring to the appropriate JMEM, by usingthe GMET, or by relying on experience.

H-7. JOINT MUNITIONSEFFECTIVENESSMANUALS

Effectiveness tables published in jointmunitions effectiveness manuals forsurface-to-surface weapons (JMEM/SS)provide guidance for determining theexpected fraction of casualties to personnelargets or damage to materiel targets. TheJMEM/SSs are published as field manuals.The manuals currently available for allsystems are listed in FM 6-141-1. The basicdata for these manuals were obtained fromtest firings, actual combat performance, andmathematical modeling. Using JMEMs todetermine attack data requires considerable

time. Because of time constraints, use ofJMEMs at battalion and battery FDC levels'is not recommended for engaging targets ofopportunity. The effects data included inthesemanuals incorporate reliability, deliveryaccuracy, and munitions lethalty against

arepresentative spectrum of targets. Thecomputational assumptions, defeat criteria,and instructions for use are included in eachmanual. Effects are listed for the followingtargets and conditions:

a. Personnel Targets. Target radii of50, 100, 150, 200, and 250 meters for cannonsystems. Data for standing, prone, andfoxholepostures are listed.

b. M a t e r i e l Ta rg e t s . A short

description of the following targets and theirvulnerabilities: 150-mm rocket and launcher,FROG-4 rocket and associated launcher,AAA fire control radar, 152-mm fieldgun/howitzer, T-55 medium tank (M109A1manual only), and ZIL-157 truck (M109A1manual only). Additional materiel targets areadded to the JMEMs as data becomeavailable. Thus, manuals for some systemswill include more targets than those for othersystems.

c. Environment. Open terrain, marshgrass, and temperate forest.

d. Methods of Delivery.adjusted and met + VE.

Observer

e. Battery Formations. Lazy W, star,and diamond.

f. Ammunition. High explosive, 1CM,and chemical.

CAUTION: There is no assurance thatthe expected fraction of damage orcasualties will be provided by anynumber of volleys in a given situation.Although not precisely within th emathematical definition, the method ofaveraging data used for the tables willresult in less damage being realized forapproximately 50 percent of the roundsand, conversely, greater damage for theother 50 percent of the rounds.

H-6



FM 6-40

munitions (for example, smoke, illumination,and special ammunition). The incendiaryeffects of munitions may make areas

untenable for supported forces. These effects

can also deny the enemy use of selectedterrain.

(4) Effectiveness. When properlydelivered agains t appropriate targets,

artillery fire support can be the decisive

factor in a battle. The FDO must ensure that

maximum effectiveness is attained from

every mission fired. To match a munition to a

target, the FDO must know what damage a

munition can produce as well as the damage

required to defeat a target. The lethality of a

munition must be matched to the specific

vulnerability of the target. Thus the FDO

must understand the damage potential

(blast, cratering, fragmentation, incendiary,and penetration) of specific munitions.

Specific information regarding the effects of

various munitions is found in the appropriateJMEM, FM 6-141-1, and FM 6-141-2. How to

predict weapon effects will be discussed laterin this appendix.

b. Weapons.

(1) Caliber and type available. In

certain instances, an FDO may control the

fires of reinforcing or general support

reinforcing (GSR) units that are firing a

different caliber. The FDO must havea

thorough knowledge of the characteristics,capabilities, and vulnerabilities of each

weapon system. Weapons that have slow

rates of fire and poor delivery accuracy aresuited for long-range fires. Weapons thathave rapid rates of fire and good delivery

accuracy are suited for close fires.

(2) System response time. An FDO

must ascertain the urgency of each fire

mission received in his FDC. Small andmedium weapons have a quicker firingresponse time than heavy weapons. Fire

missions sent by the DS battalion to

reinforcing or GSR units require moreprocessing time than those sent directly to

the DS units' own firing batteries.

(3) Predicted fire capability. The

FDO must know the current survey,

registration, and met status of all firing units

under his control. The FFE missions should

be assigned to units that have the best

predicted fire capability.

H-5. DETERMNEfNG THEMETHOD OF ATTACK

The final step in the FDO's target analysis

is the selection of a method of attack. The

FDO must select a method of attack that

ensures target area coverage and desired

target effects. To determine the best methodof attack, the FDO must consider aiming

points, density, and duration of fires. FigureH-3 shows the method of attack selectionconsiderations.

Figure H-3. Considerations in the selection of a method of attack.SH-5



. GRAPHICALMUNITIONS EFFECTSTABLES

General. The FM 6-141 series ofnuals provides doctrine for targetysis procedures and the employment ofpon systems. The JMEMs providellent effectiveness.data. The usefulnesshe above-mentioned publications to the

O during field operations is limited byr volume, by the lack of accessibility, andhe difficulty in comparing ammunition orpon systems. The GMETs overcome thesetations by providing quick access toage comparative values for selectedations that the user may use as aeline when making the engagementsion. The use of GMETs to determineet attack data is highly recommended.

(1) A complete listing of GMETs iswn in table H-2.

(2) The unclassified GMET (trainingion for medium artillery) (fig H-4) willerally require slightly greater

penditures of ammunition than the09A1 GMET in a given situation.

. Table Description.

(1) Composition. The table consistsa body and a plastic runner or cursor. Then or clear portion of the cursor is thedow. The marginal notes provide certainumptions for the GMET calculations.

(2) Content. The user can determinenumber of battery or battalion volleys

uired to achieve a specified averagepected fraction of casualties against enemysonnel in the open in either an offensive orefensive posture. The user can also

determine the expected effects to be achievedwith one battery or battalion volley.

(3) Organization. All of the fiveblocks on each side of the table (for example,observer adjusted, MET + VE 0 TLE) areidentical in format. Provision is made fortarget location error (TLE) of up o 250 metersand for three levels of effectiveness inaddition to the effects of one volley.

(4) Target size. Data are providedfor personnel targets ranging in size from 50to 250 meters radius. The cursor is labeledwith these radii of target (RT) for both batteryand battalion volleys. The assumed radii forvarious size elements (for example, squad 50to 100 meters) are listed on the cursor. Theuser should consider the following additionalinformation when using the GMET:

(a) If the dimensions of a target areless than the width of an Open sheaf or lessthan 250 meters deep, consideration shouldbe given to firing a converged sheaf toincrease the expected fraction of casualties orto decrease the required number of volleys.

(b) If the dimensions of a targetexceed the width of an open sheaf or exceed adepth of 250 meters, consideration should begiven to creating multiple aiming points, tofiring sweep and/or zone, or to shifting fires.

(c) If the target is long and narrow,

such as a convoy on a road, a series of50-meter targets preceded by a multiplier tocover the length of the convoy can be used todetermine the number of volleys to attack thetarget provided special corrections areapplied to the weapons.

(5) Target postures. See note 6 onthe right edge of the body of the table for anexplanation of the postures used incomputing weapons effects.

Table H-2. Available GMET.

National Stock Number Description

1220-01-021-7278 (C) Scale, Graphical Munitions Effects (GMET--JMEM) for M102(U)

1220-01-021-7279 (C) Scale, Graphical Munitions Effects (GMET-JMEM) for M109A1(U)

1220-01-021-7276 (C) Scale, Graphical Munitions Effects (GMET-JMEM) for M110(U)

1220-01-021-7277 Scale, Graphical Munitions Effects, Training (GMET-JMEM)

Note . These tables are expendable itemsauthorized by CTA 50-970.

'~ I___________________________

1~SSIFt ED

NOTES1. LAZY WFORMATION2. VOLLEYS PERFIRING UNIT AT

2/3 MAXIMUMRANGE.3. ENTER OF

BATTERY AIMED

AT TARGET CENTER.4. P = PROHIBITIVE

OVER 30 BATTERY

VOLLEYS.

E = EXCESSIVE FOR

SPECIFIED FRACTIONOF CASUALTIES.

TRAINING EDITION FOR MEDIUMOBSERVER ADJUST

.30 .20 .1Fo|- T|€M _PitIIIcMIPD Iy

173 E 32 5 E E71E

221 10 4 1 17 7 31 9 4

281 13 5s 271 o0 3 112 1P1 24l 7 P]16 421 1i0

5l 3[E 1 3[ 21 E EIE

71 IE |42|3E 2[L101 51 2 6. ,E 31P1i 8l.. 3 1°0 i E 6Lp' P 5 P 61 3± 10 6S

1220.01.021-7277

%CASFA/SHELLRT50

BTRY 100VOL 150

200250

50BN 100VOL 100

200250

ASSYNED RT'SSOD 50-100mHQ 100-150mPLT 150-200mCO 250mBN 250-500m

UNC LASS IFIE

GRAPHICAL MUNITIONS EF

NOTES TRAINING EDITION FOR MEDIUM FIELD ARTILLERY

1. LAZY W OBSERVER ADJUSTED MET + VE 0 TLE MET + VE 75 TL

FORMATION .10 .05 .02 1 VOL .10 .05 .02 1 VOL .10 .0 .04 %CAS

Z VOLLEYS ER PDBVTRCM

PD VT 1CMPDrVT 1CM PD VT 1MPD VT 9CM PYDVT 9CM PD VT 1CM VT 9CMPDVT 9MP VVL PH

FIRING UNIT ATV R0

2/3 MAXIMUM P 16 3 P 51 E 8 E E .01 .03 .06 P 291 5 P 12 P 2 E .01.02 .05 P P 7P

RANGE. P204 P 6 E 1 2 1 E .01.02.06 P P 5 P14 1 P3 E.01.01.05 PP 8 P B

3.CENTER OF P92526 P1 226

3 E . 01 .01 .05 P P 7 P202 P4 E -. 01 .04 P P 9 PV

BATTERY AIMED P 2 P 8 Pl2 P7 E -. 01 .04 P I P 9 P 293 P8 E -. 1* .03 PP111 P0

AT ARGET CENTER. P P 12 1A27 5 p 11 1T.01 .021 PI P 13, P P 5 P 12 1- .02 P IP115P

4. PROHIBITIVE

OVER 0BATTERY P 2 E 1 E E E E E .03.0718 P 8 E P 2 E 3 E E .02.0415 P P-1 EP3 5S

VOLLEYS. P 4 E 9 E E I1E.E .02 .06161PlO E P 3 E 4 E E . 01 .0313 P P E

E=EXCESSIVE FOR P 6 E1 P 3 E SE E .0.0413 P P E P 4 E 6 E.E.01 .03.111pp 2 VOL lOC

WEIS DRCIN P 1 P 6 E 7 E E .01 .03.10, P P 2 P 7 ElO0 1 E .01 .02 .09 P P 3Z p 0SPECIFIED FRACTION 725(

OF CASUALTI ES. Pe PO EP3 E . 01 .01 .07 P P 3P E P3 E .06 p

1220-01-021-7277

Figure H-4. Graphic munitions effects ta

H-7

ASSIFIEDIONS EFFECTS TABLE

'--''-:--- ' PIERSONNEL IN OFFENSIVE POSTURE

MMVE 1CM 0D E 1 M T 1 PM TC V T

R Y0 1VLL 0L2 0Y1 • P.0V 3

ION VOLLEYS _ _ __1_ _ _II_ _21'_5_-_ 01 09

E 42 E .04 .06 .231PP 4 P1023£148E2.02. 4P.82.01.2.083 63' 2 . 03 05.201P p lP 3 P8415 E2 . 02 03.140 P P P P P 12 P P 2 -. 011 .08

2 9 3 E . 03 .0416 P 1 P PI P 3 l5 E .-. 01:.0 P P P P P 5 P P 3 1--.01

4A3 0 E .02 .01 20 P P 62 P P 4 P162 . 0 0 PP P 6 P 3 -. 0 1 . 0 3

.ASSI.1 0 41PIP17 1 01P PF ED..0

.N5. %AVERFRAC6. T

a. OFIR1/21/2

VOb.FIR1/21/2

SUBAL

7. I

MET + VE 0 TLE.30 .20 10 1VOL

PD VT CM PDI'vT ICM PDVTIICMI PD VT ICM

P 17 P 11 3 21 6 E 1.01 .03 .12

201 5 P 12 3 28 7 E .01 .02 .11P2 P 1 5 4 P 101 1 1.01 .02 L .10

p P 7 P 23 4 P 14 2 -_.01 .08

P 9 P P 6 P 19 3 -. 01 .05

P 161 1" 7 4"" E 31 2 E 1.0)6".09 .30PI 7 2 S 41 E 3 1 2 E 1 . 0 5 . 0 8 .27

P1 9, 3 9 5 E 4 3 E-1.04.o07 .23P 4 P 6 2 5 4 E .03 . 0616s

p 5 P 10 3 8 6 E .02 .05 .13

,8 -1 .- 6

© © ©

DEFENSIVE POSTURE5. %

MET + VE 150 ,rLE + VE 250 TLE

.10 1.00 j1 VL .2 I VOL AVE... 10 .05' " t'0(2 ' "I VOL ] .02 [1 VL_ FRA

PDvTIICMIPDIVTICP CMiPDAViTIICMIPDIVT IICl41lcM PD VTJ 9CM PD VT ICM 6 RA

aP P 12 P 27 4 P 10 E- .01' .03 ASSYNED'RT'S 11 P 20 2 - - .02 FR

PP 12 P P 5 P1 1 -. 01 .02 S0D 50-100m 12 P22 2 - - .02

P P 14 P P 6 P 12 1 - .01 .02 HO 100-150m 13 P 24 3 - - .01

p P4 P ,. . -P •1Jl.. .. , 1-2p P 18 P P 7 P 4 1 - - .02 PLTI150-200m 3 P P 3 - - .01 VO

P P P 20 P P 8 P 17 2-- .02CO 250m 14 'P P 4 - - .01 V O

I B N 2 5 0 - 0 0 m .... b.

p P - 2 P 9 E p 2 E .012.02.07 2 P S E .01.01 .04 FIR

p P 2 PlO E P 12 E .01 . 02 .07 '2 p 5 E - .01 .04 1/2

P P 3 P P E P 2 E . 01 .01 .06 3 P 6 E -. 01 .03 1/2

p P 4 P P 2 Pj'4 E -. 01.05 3 P 7 E - .01 .03 SU

SP P 7 E - - .03 AL

D . -6P- " "" 77. I

© © ©

les.

(r-))



FM 6-40

(6) Percentage of casualties. Theercentage of casualties (%CAS) is expressed

as the average expected fraction ofcasualties. For example, if on one occasion,the fraction of casualties is 50 percent; onAnother occasion, 25 percent; and on a thirdoccasion, 25 percent; the average expectedf action of casualties would be 33 percent.There is no probability or assuranceassociated with the percent of casualties.iAgainst personnel targets in an offensiveposture, the assumed desired average,expected fractions of casualties are 30, 20,and 10 percent. For targets in a defensiveposture, the assumed casualties are 10, 5, and2 percent. The casualty percentages for thedefense are lower than for the offense becauseof the greater shielding of targets in adefensive posture. Shown also is the average

expected fraction of casualties for one battery,and one battalion volley. The number ofexpected casualties is the product of theaverage expected fraction of casualties andthe number of personnel in the target area.

(7) Shell/fuze combinations. The'GMET contains effectiveness data for the'standard HE shell (for example, M107 for155-mm howitzer) with PD or proximity (VT)fuze and the antipersonnel improved

conventional munitions.(8) Volleys required. The GMET

lists the number of battery or battalionvolleys required to achieve a specifiedpercentage of casualties against personnelfor each size target, method of delivery,shell-fuze combination, and target locationerror. The letter P indicates that the number,of volleys required is over 30 battery volleysor 10 battalion volleys and is consideredprohibitive, because any additional volleys,will not achieve a significant increase incasualties. The letter E indicates that the,casualties obtained would be more than thespecified casualty level.

(9) Met + VE delivery technique.Effects tables are based on the average,weather change that could take place whenusing a 4-hour met message. Thus, whenusing met data that are older than 2 hours,more volleys will be required to achieve the~desired fraction of casualties. Conversely, if~more accurate data are being used, fewervolleys will be required.

jH-8

DOUT H-7

(10) Observer adjustedtechniques. The tables are bassumption that the observer hasufficient adjustment to place tthe sheaf(s) on the adjusting poi

c. Other Considerations.

(1) Volley versus time-fires. The GMET assumes thabattalion volley fire will be used. Teffects are achieved when surprisemaximum intensity are used. Noof the TOT technique will reduceexpenditure for a given situationthe reduced time the enemy hasincrease his protection.

(2) Materiel targets (areaof he weapons is considered effectiarmored targets in area fire. Theof obtaining a hit is remote. Unthere will be bonus effects at timeshould be considered only as boand should not be relied on. This ithat exposed personnel on ormateriel targets cannot besuccessfully with artillery.

(3) Round-off rule.instances, the required expendit

required casualty level may appeaon the basis of one-volley effects.Training Edition, Defensive POMET +VE 250 TLE, 50 M RT.) Thecalculated to four decimal places ato two decimal places; thus, theeffects of .02 may range from .01nd either one or two volleys mayto achieve exactly .02 level of effe

EXAMPLE:

Given:Unit: 155 155-mm howitzer battaTarget: Platoon of infantry in t(assume offensive posture, radius150 meters, target ocation error fAmmunition: Sufficient convammunition with VTfuze is availab

Effects desired: Minimumexpected raction of casualties of 3Procedure: Slide the cursor to Mdelivery technique 0 TLE on theposture



FM 6-40

side of the GMET. Look under the window for30 percent casualties to see that ninebattalion volleys of VT-fuzed ammunitionwould be required to achieve 30 percentaverage expected fraction of casualties.

Solution:

The FDO orders the battalion to fire ninevolleys VT fuzed ammunition to achieve 30percent average expected fraction ofcasualties.

H-9. QUICK REFERENCETABLES

a. If JMEMs or GMETs are not available,the FDO can use the guide for cannon attackof typical targets (table H-3). The table lists

selected personnel and materiel targets andindicates the order of effectiveness of eachshell/fuze combination. Targets notindicated should be equated to targets thatare listed. The table can be used for allcalibers. Use of the table is explained in thenotes.

Table H-3. Guide for cannon attack of typical targets.

TARGET RESULTS

TYPE OBSERVATION WEAPON PROJECTILE HE FUZE DESIRED REMARKS

PERSONNEL

In open or in Observed/ All HE Proximity Destruction Massing is required. 1

foxhole with- unobserved (VT), time TOT missions are most

out overheadeffective. First volley is

ocoverhmost effective.cover___________

All HE Proximity Neutralization Massing is required(VT), time except for small targets.

All HE Quick, Suppression Response time is criticalproximity, against active targets.time Preferred fu-ze is prox-

imity.

All APICM NA Destruction Massing is required on

large targets. TOT mis-sions are most effective.

All APICM Neutralization Cannon battery volleysare sufficient.

In foxhole Observed All HE Quick/delay Neutralization Massing is required. TOT

with over- (ricochet) missions are most effec-

head cover tive. Consider use of WPto drive personnel out offoxholes.

All HE Proximity, Suppression Response time is criticaltime, delay, against active targets.quick Proximity fuze is pre-

ferred. Consider use of

smoke for obscuration.

All APICM NA Neutralization Massing is required.TOTmissions are most effec-tive.

I1APICM NA Suppression Consider use of ICM onintermittent basis forincreased effectiveness.

In dugouts Observed All (prefer- HE Delay, Destruction Use direct fire or assault

or caves ably155 mm quick techniques. Fire HEor larger) quick at intervals to clear

away camouflage, earthcover, and rubble.

H-9



FM 6-40

Table H-3. Guide for cannon attack of typical targets (continued).

TARGET RESULTSTYPE OBSERVATION WEAPON PROJECTILE HE FUZE DESIRED REMARKS

Attacking Observed 105 mm Beehive Time Destruction Set fuze to detonate onbattery All HE the ascending branch ofposition APICM the trajectory for close-in

defense of battery area.

VEHICLE2

Tanks Observed All HE Proximity, Suppression Fire projectile HE to forcetime tanks to button up and

personnel outside totake cover or disperse.WP may blind vehicledrivers, and fires may bestarted from incendiaryeffect on outside fueltanks. WP or fires may

obscure adjustment.DPICM is preferred mu-nition for unobservedfire.

Observed/ 155 mm DPICM NA Suppression See paragraph 7-7, FMunobserved 6-141-2. Massing is

effective; ICM is pre-ferred.

203 mm DPICM NA Suppression See FM 6-141-2. Mass-ing is effective; ICM ispreferred.

Observed 155 mm FASCAM NA NA Both antitank and anti-personnel projectilesshould be used.

Observed 155 mm Copperhead NA Destruction

Direct fire 105 mm HEP, HEP-T NA DestructionHEAT

Armored Observed All HE Proximity, Suppression Force vehicles to buttonpersonnel time up and personnel out-carriers side to take cover or dis-

perse.

Observed/ 155 mm APICM NA Neutralizatio See FM 6-141-2. Mass-unobserved DPICM ing is effective.

203 mm APICM NA Neutralizatio See FM 6-141-2. Mass-DPICM ing is effective.

155 mm FASCAM NA NA See remarks for tanks.


Trucks Observed All HE Proximity, Destruction 1CM is preferred muni-unobserved time tion.

155 mm DPICM NA Destruction

203 mm DPICM NA Destruction

H-I 0

S



FM 6-40


OBSERVATION

Observed

TARGETTYPE

WEAPONS

Antitankmissile

Air defense

ZSU-23-4SA 6

~mif

Observed

Unobserved

~WEAPONF

All

155 mm

203 mm

All

All

All

All

155 mm

All

All (less105 mm)

155 mm

I I

PROJECTILE

HE

HE

DPICMDPICM

HE

HE

HE, WP

APICM

FASCAM

HE, WP

DPICM

FASCAM

Quick

Proximity

NA

Quick

Quick

Proximity,time

NA

NA

Proximitytime

NA

NA

REMARKS

Response time is critical.Intermittent fire may berequired. Change to fuzeproximity or DPICM formateriel damage if anti-tank guided missile plat-form on BRDM is raised.

11 I

DESIRED

Suppression

I

JI-

-JL7

Firepower kill

NA

Suppression

Suppression

NA

WP is used to ignitemateriel. See personneltargets for results de-sired.

See personnel targetssection for results de-sired. TOT missions aremost effective. Massingis usually required.

Use ADAM projectile inconjunction with HE orICM for sustained ef-fects.

WP is used to ignitemateriel.

CM is preferred muni-tion.

Use ADAM projectile inconjunction with HE orICM for sustained ef-fects.

H-1I

Observed/unobserved

SA 8,9

Towed FAmortarsmultiplerocketlauncher

Self-propelledFA battery

Response time is critical.Intermittent fire may berequired.

Firepower kill

Firepower kill

Firepower kill

Suppression

Smoke may also be usedto obscure gunner's lineof sight to friendly air-craft. ICM is preferredmunition. Consider con-

verged sheaf if weaponis point target and accu-rately located.

i it 11 11 M

Firepower killil Same as above.

Unobserved

All

R

IF-



FM 6-40


TARGET1RESULTSOBSERVATION WEAPON PROJECTILE HE FUZE DESIRED

Surface-to-surfacemissile

MISCEL-

LANEOUS

Radar

Artillerycommandand obser-

vation posts

Unobserved

Unobserved

Observed

-if

All (less105 mm)

All (less105 mm)

All

155 mm

203 mm

All

155 mm

203 mm

HE

DPICM

DPICM

iFE

DPICM

DPICM

HE

DPICM

DPICM

3'

Proxim ity,

time

NA

Quick, timeproximity

NA

Quick

NA

Firepower kill

Firepower k

Firepower ki

Firepower kil

Suppression

Suppression

ill

SREMARKS

Use converged sheaf Htime and target locatioraccuracy permit. TLE irexcess of 200 metersrequires massing olfires. ICM is preferredmunition.

Same as above.

Use converged sheaf iftime and target locationaccuracy permit. TLE inexcess of 200 meters re-quires massing of fires.1CM is preferred muni-tion.

i

I

I

Intermittent fire may berequired. HE is preferredmunition when re-sponse time is critical.

I

Command Unobserved All HE Proximity, Neutralization Use ADAM for sustainedpost time or effects. When targetdestruction contains personnel and

light materiel targets,DPICM is preferredmunition.

155 mm DPICM NA NA See above.

203 mm DPICM

Supply Unobserved All HE, WP Quick Fires Large target locationinstallationerrors require massingto ensure target cover-age.

Boats Observed All HE Time Suppression Attack as moving per-

sonnel target.

H-12

I

-- Jt

it JLt

)I

I

Same as above.

11ff



FM 6-40


TARGET RESULTS

TYPE OBSERVATION WEAPON PROJECTILE HE FUZE DESIRED REMARKS

Bridges Observed/ All (prefer- HE Quick, CP, Destruction Direction of fire is pref-

unobserved ably 155 mm delay erably with long axis of

or larger) bridge. Destruction ofpermanent bridges isbest accomplished byknocking out bridge sup-port. Fuze quick is usedfor wooden or pontoonbridges.


Fortifications Observed All (prefer- HE CP, delay, Destruction Use highest practicalably 155 mm quick charge in assault and

or larger) direct fire.

155 mm Copperhead NA DestructionJ up, -.. ..- iIiIIIIl

1Targets, regardless of type, with an estimated target radius of greater

than 150 meters usually"require massing

for effective attack.2The first objective of firing on moving vehicles is to stop the movement. For this purpose, a deep bracket is

established so that the target will not move out of the initial bracket during adjustment. Speed of adjustment is

essential. If possible, the column should be stopped at a point where vehicles cannot change their route and where

one stalled vehicle will cause others to stop. Vehicles moving on a road can be attacked by adjusting on a point on

the road and then timing the rounds fired so that they arrive at that point when a vehicle is passing it. Afiring unit

or units, if available, may fire at different points on the road simultaneously.

b. The expected area of coverage table FDO can use table H-4 to determine the size'(table H-4) can be used to determine the target that can be attacked by use of batteryappropriate size of a battery one volley or or battalion volleys. The density of coverage

battalion one volley of both HE and ICM for is not considered, but the density of coverage

the various caliber weapon systems. The of 1CM is much greater than that of HE.

Table H-4. Expected area of coverage (meters).

MUNITIONS 105 mm 155 mm 203 mm

ICM (AP) BTRY 0 BTRY Q BTRY

BN® (BN (BNQ(

Square 250 x 250 266 x 266 239 x 23 9

380 x 380 390 x 390 320 x 32 0

Circle 140 150 135

(Radius) 215 220 180

HE BTRY 0 BTRY Q BIRY Q/07____ _a_07%MNQ B N O B N Q

Sqae248 x 248 275 x 275 239 x 239

380 x380 390Qx390 319 x319

Circle 140 155 135

(Radius) 215 220 180,

H-13



FM 6-40

c. The expected fraction of casualties/personnel table (table H-5) can be used todetermine the optimum method of attackinga personnel target of 50 meters radius toachieve the commander's criteria. Table H-5cannot be used for materiel targets.

Table H-5. Expected fraction of casualties/personnel.

PROJECTILE IF TARGET RADIUS 50 = METERS, THEN:

ICM (AP) HE/VT HE/PD

BTRY 1 07 07 04105 mmBN 1 20 20 12

BTRY 1 15 05 03155 mmBN 1 35 16 11

BTRY 1 15 03 02203 mm

BN 1 38 10 05

H-14



FM 6-40

APPENDIX I

SAMPLE PROBLEM KNOWN DATA

I-1. KNOWN DATAThe known data in tables I-1 through 1-8

are used for all sample problems throughoutthis publication unless otherwise noted.

a. The map used for all sample problems

is the Lawton, Series V783, Sheet 6353 II,1:50,000 map.

b. The azimuth of lay for all batteries is6,350 mils.

c. The MVVs (table 1-6) are for all types ofammunition unless otherwise noted. Thevalues are the averages of the weapon MVVs.

d. The target numberihg blocksauthorized are FDC: AC7800 to AC7850 andFIST: AA7050 to AA7199.

Table i-1. Battery locations.

GRID ALTITUDE

BATTERY1 COORDINATES (METERS)

A 61321 32489 335

B 60858 32640 352

C 60478 32859 348

1All batteries are 155-mm M109A3 howitzer batteriesexcept where otherwise noted for instructionalpurposes.

Table 1-2. Observer locations.GRID ALTITUDE

OBSERVER COORDINATES (METERS)

01 59748 33872 370

02 62213 34190 391

Radar 61550 32572 358

Table 1-3. Targets that are known points.

GRID ALTITUDETARGET COORDINATES (METERS)

AA7056 6155 3670 389

AA7059 6258 3835 363

AA7052 5950 3706350

AA7054 6234 3826 390

AA7050 6068 3644 363

Reg Pt 1 60553 37465 377

Reg Pt 2 63341 37425 376

Table 1-4. Piece locations for Battery A (fromgeographical battery center).

LOCATION LOCATIONGUN (RIGHT/LEFT) (FORWARD/BACK)

1 R230 F250

2 R10 F220

3 R60 F25

4 L130 B2 0

5 L35 B240

6 L270 B295

Table 1-5. Platoon center locations forbattery A.

GRID ALTITUDEPLATOON COORDINATES (METERS)

RigtOO 61441 32624 355

Center 61291 32491 355

Left 6117 1 32 224 355

I-1



FM 6-40

Table 1-6. Muzzle velocity variations.

MUZZLE VELOCITYPLATOON VARIATION

Right +1.0 m/s

Center 0Left -0.8 m/s

Table 1-7. Lot designations.

PROJECTILES LOT PROPELLANTS LO T

HE X GB YADAM-S B GB (ODD LOT) 0ADAM-L C M206 JDPICM I M80 (203-mm

RAAMS-S E example) CRAAMS-L D WB PHE-RAP M M119A1 RNUC-RAP Q M207 GHC H M188 (203-mm

WP (M825) W example) AWP zCHEMICAL (GB) GCHEMICAL (VX) VILLUMINATION LNUCLEAR N

Table 1-8. Call signs.'

AGENCY CALL SIGNS

FIST B6H23Battery A FDC T2G12Battery B FDC T2J27Battery C FDC T2V54Battalion FDC Z4E76

'Digital addresses are not used in the examples.

P[2. ILJLTIPLOT GIRTSETTEING

The following multiplot GFT setting is usedin the examples unless otherwise noted:

GFT A: Chg 4, Lot XY,Rg 3730, E1 225, Ti12.8

GFT A: Chg 4, Lot XY, Rg 5140, El 335, Ti18.9GFT A: Chg 4, Lot XY, Rg 5580, El 374, Ti21.0Average total deflection correction: L2Average GFT deflection correction: R4

Note. For all problems and examples, useTFT 155-AM-2 and associated graphicalequipment when possible.

1-3. STANDI[NG OPERATINGPROCEDURES

The following is a summary of the unitSOPs that apply to the examples in thispublication.

a. Normally, the unit fires one round,shell HE, fuze quick in adjustment. The oddlot powder will be used in adjustment beforethe main lot (registered) that is to be used forfire-for-effect missions.

b. In fire-for-effect missions, shellDPICM is fired, and the registered powder lo tfrom the DPICM self-registering moderegistration is used.

c. In the interest of speed and accuracy,the unit uses the hasty correction tables inappendix A in adjustment and fire-for-effectmissions. Platoon locations, plotted on thefiring chart, are used in immediate-typemissions instead of the hasty correctiontables.

Note. Most fire mission examples in thispublication do not have a gun located overthe geographical battery center; this wasdone to show the technique of applyingspecial corrections.

d. Immediate suppression missions arefired with a platoon two rounds, shell HE,fuze VT. Immediate smoke missions are firedwith a platoon two rounds. The left gun firesshell HG, fuze time, and the right gun firesshell WP, fuze quick.

e. The computer selects and assigns thenext unassigned target number to eachmission.

1-2

S



FM 6-40

APPENDIX J

NEW DEPARTMENT OF THE ARMY FORMS

The new DA forms shown in figures J-1 through J-6 are for use in field

artillery cannon gunnery procedures. DA Form 5336-R, DA Form 5337-R,

DA Form 5338-R, DA Form 4982-R, and DA Form 4982-1-R are reproducible.

J-1



m

203-MM NUCLEAR COMPUTATION WORK SHEETFOR M753 ROCKET-ASSISTED PROJECTILE

(Use with firing table 8-5-1 .)

For use of this form, see FM 6-40; proponent agency is TRADOC.

DA FORM 5336-R SEP 84 (CONFIDENTIAL WHEN FILLED IN)(This form together with DA Form 5337-R, Sep 84, replaces DA Form 4207, Oct 78)

DATE-TIME GROUP BATTERY PIECE NUMBER TARGET CHARGE

K-TRANSFER

STEP PROCEDURE VALUE STEP PROCEDURE VALU

1 ALTITUDE OF TARGET (1 METER) HIGH-EXPLOSIVE/ROCKET-ASSISTEDPROJECTILE ROCKET MOTOR TEMPER-

_ _ _ _ _ _ _ _ _ 21 ATURE RANGE CORRECTION

2 HEIGHTOF BURST ABOVETARGET (1 METER) (TABLE El) (1 METER)

3 ALTITUDE OF BURST - +g) (1 METER) 22 DIFFERENCE(21 ) (1 ETER)

4 ALTITUDE OF BATTERY (1 METER) 23 CORRECTED RANGET)23 ( + 13 + 19 + J) (10METERS)

HEIGHTOF BURST ,.-_ _ _5 ABOVE GUN ( -- ) (1 ETER) ELEVATION "- 1 (HIGH-EXPLOSIVE/

24 ROCKET-ASSISTED PROJECTILE

6 CHART RANGE TO TARGET (10 METERS) GFT SETTING) (1 MIL)

SITE (GFT, ERTICAL INTERVAL

7 COMPLEMENTARY RANGE (TABLE B) (1 METER) 25 ,. L AT RANGE - ) (1 IL)

ENTRY RANGE ('6 + -j) QUADRANT ELEVATION FOR

8 26 HIGH-EXPLOSIVE/ROCKET-ASSISTED

( _______[1 METER]) (100 METERS) PROJECTILE ( +- ) 11 IL)

ZL27 ANGLE OF SITE (GST, C-

AMUZZLE VELOCITY (TABLE E) 2 AND D-SCALES) (1 MIL)9 (NUCLEAR PROJECTILE POWDER ..

(0.1 ETER ELEVATION + COMPLEMENTARY

TEMPERATURE [ O-F]) PER SECOND) 28 ANGLE OF SITE (27

)(1 IL)

/A MUZZLE VELOCITY(TABLE E) FUZE SETTING '- [I (HIGH-EXPLOSIVE/(HIGH-EXPLOSIVE/ROCKET- 29 ROCKET-ASSISTED PROJECTILE

10 ASSISTED PROJECTILE POWDER KGFTSEnING) (0.1)(0.1 ETER

TEMPERATURE [ OF]) PER SECOND)

.... . .. ........ _ BALLISTIC FUZE CORRECTION

11 DIFFERENCE) -j -J ) (0.1) 30 FOR NUCLEAR PROJECTILEDECREASE/INCREASE (PART 2, ABLE B) (0.1)

UNIT CORRECTION FUZE SETTING TO FIRE12 (TABLEF, COLUMN 10/11) (0.1) 31 ( + ) (0.1)

CORRECTION FOR PROPELLANT 32 CHART DEFLECTION TO TARGET (1 IL)

13 CHARGE TEMPERATURE) (- x ) (1 METER)

14 NUCLEAR PROJECTILE WEIGHT (0.1 POUND) DEFLECTION CORRECTION (GFT

I.. ... . 33 DEFLECTION CORRECTION

HIGH-EXPLOSIVE/ROCKET- + DRIFT'-ELEVATION) (1 IL)

15 ASSISTED PROJECTILE WEIGHT

((PAGE VI, TFT) (0.1 POUND) BALLISTIC DEFLECTION CORRECTION

(0.1 POUND) (PART 2, TABLE A)(16 DIFFERENCE 14 - 1 DECREASE/INCREASE [0...... 111mil

DiFFERENCE INSQUARE (0.1) D'EFLECTIONTO FIRE '

17 WEIGHT (16'

+ 2.5) DECREASE/INCREASE ( + J+ ) (i MIL)

t--R-tRE_ CTIQNTALE-,__ _________QUADRANTELEVAT1ON-FOR-HIGH

COLUMN 18/19) (1 ME-TE-R) 36 -EXPLOSIVE/ROcKET-ASSIsTED"_____ PROJECTILE (1 MIL)

CORRECTIONOR PROJECTILE ,,_____________________________

19 WEIGHT) 17 X 18 ) (1 METER) BLITCCRETO O

NUCLEAR PROJECTILE ROCKET TABLE A) (1 MIL)

20 MOTOR TEMPERATURE RANGE QARN LVTO ...

CORRECTION (TABLE EI) (1 METER) QUADRAELEVATION) 1 IL

38... TOIEii~) 1ML



203-MM NUCLEAR COMPUTATION WORK SHEET FOR M422A1

For use of this form, see FM 6-40; proponent agency is TRADOC.

- i

KNOWN DATA

TARGET ALTITUDE CHART RANGE DATE

PROPELLANT TEMPERATURE HIGH-EXPLOSIVE PROJECTILE NUCLEAR PROJECTILEWEIGHT TIMEWEIGHT

ENTER THE INTRODUCTION TO FT 8-ADD-H-1 FOR CORRESPONDING CHARGE FROM 1 ABOVE

STEP PROCEDURE VALUE

3 RANGE CORRECTION FOR PROPELLANT TEMPERATURE (FT 8-ADD-H-I, TABLE C).

4 RANGE CORRECTION FOR PROJECTILE WEIGHT DIFFERENCE (FT 8-Q-1, TABLE F).

5 -3 W + CHART RANGE = CORRECTED RANGE.

6 ADD TARGET ALTITUDE AND HEIGHT OF BURST.

7 SUBTRACT BATTERY ALTITUDE FROM STEPf6-] VERTICAL INTERVAL.

8 DETERMINE SITE CORRESPONDING TO STEP W G S ).

9 IF ERTICAL INTERVAL IS REATER THAN OR EQUALTO 100, SE C- AND D-SCALES TO DETERMINE ANGLE OF ITE;IF ERTICAL INTERVAL IS ESS THAN 100, GO TO STEP 11

10 SUBTRACT STEP F'9 FROM STEP = COMPLEMENTARY ANGLE OF SITE.

11 DETERMINE ELEVATION -- ORRECTED RANGE (STEPW).

12 DETERMINE FUZE SETTING -- ELEVATION + COMPLEMENTARY ANGLE OF SITE (STEP j)

13 ADD STEPS [q] AND1 HIGH-EXPLOSIVE QUADRANT ELEVATION.

ADD CHART DEFLECTION + DRIFT + GFT DEFLECTION CORRECTION - HE DEFLECTION.

14

15 CORRECTIONS TO HIGH-EXPLOSIVEQUADRANT ELEVATION FOR SHELL NUCLEAR (FT 8-ADD-H-, TABLE A).

16 CORRECTIONS-TO HIGH-EXPLOSIVE DEFLECTION FOR SHELL NUCLEAR (FT 8-ADD-H-1, TABLE A).

17 CORRECTIONS TO HIGH-EXPLOSIVE FUZE FOR M591 FUZE (FT 8-ADD-H- TABLE B).

18 ADD STEPS 12 AND 1 NUCLEAR TIME M591

19 ADD STEPS 14 AND 16 - NUCLEAR DEFLECTION.

20 ADD STEPS 13AND[ ~-UCLEAR QUADRANT ELEVATION.

DA FORM 5337-R SEP 84 (CONFIDENTIAL WHEN FILLED IN)(This form together with DA Form 5336-B, Sep 84. replaces DA Form 4207. Oct 78)



C

E M A K

COMPUTER CHECKLISTFor use of this form, see FM 6-40; the proponent agency is TRADOC.

FIRE ORDER STANDARDS FIRE FOR PIECE DISPLACEMENT DATAADJUST FIRE EFFECT

1. NIT TO FIRE GUN DISPLACEMENT

2. ADJUSTING ELEMENT/METHOD OF FIRE OF ADJUSTING ELEMENT NUMBER GRID LATERAL RANGE

3.BASIS FOR CORRECTION 1

4. DISTRIBUTION 2

5. PROJECTILE3 -__3_....

6. AMMUNITIONLOT/CHARGE 4

7. FUZE 5

8. NUMBER OF ROUNDS 6

9. RANGE SPREAD, LATERAL'SPREAD, ZONE OR SWEEP AIMING

10. TIME OF OPENING FIRECIRCLE

11. TARGET NUMBER.4 PRIORITY TARGET INFORMATION

FIRE FOR FINAL PROTECTIVE FIRE/

FIRE COMMAND STANDARDS ADJUST FIRE EFFECT . COPPERHEAD

12. WARNING ORDER , GRID TARGET NUMBER

13. PIECE TO FOLLOW/PIECE" O FIRE/METHOD OF FIRE

14. SPECIAL INSTRUCTIONS.

15. PROJECTILE

16. AMMUNITION LOT

17. FUZE/FUZE SETTING

18. DEFLECTION

19. QUADRANT ELEVATION

20. METHOD OF FIRE ,

BATTERY 25. FIRE PLAN

AMMUNITION COUNT BATTERY DATA GRID/ALTITUDE AZIMUTH CALL SIGN

KNOWN TIME UNITPOINT/ ON OFTARGET LOCATION TARGET FIRE

BATTERY GFT SETTINGS

21. HIGH EXPLOSIVE

22. DUAL-PURPOSE iMPROVED CONVENTIONAL MUNITIONS

23. ROCKET-ASSISTED PROJECTILES

24. NUCLEAR STANDARD I I I

REMARKS

DA FORM 5338-R SEP 84



49

DAEPOWDERGRU

MUZZLE VELOCITY RECORDFor use of this form, see FM 6-40; the proponent agency is TRADOC.

FIRST LOT CALIBRATION

SHELL/FAMILY FIRST POWDER LOT NUMBER GUN NUMBER/CHARGE FIRED

ITEMS 1/ 2/ 3/ 4/ 5/ 6/

1. WEAPON BUMPER NUMBER

2. WEAPON TUBE NUMBER

3. FIRST LOT CHARGE STANDARD MUZZLE VELOCITY

4. CALIBRATEDMUZZLE VELOCITY

5. FIRST LOT PIECE MUZZLE VELOCITYVARIATION

SECOND LOT CALIBRATION/INFERENCE

H L YPOWDERRO UGUN NUMBER/CHARGE FIRED

ITEMS 1/ 2/ 3/ 4/ 5/ 6/

6. SECOND LOT CHARGE STANDARD MUZZLEVELOCITY

7. SECOND LOT CALIBRATED MUZZLEVELOCITY

8. FIRST LOT PIECE MUZZLE VELOCITY VARIATION(5)

9. CHANGE IN MUZZLE VELOCITY VARIATION

10. FIRST LOT PIECE MUZZLE VELOCITY VARIATION(5)

11. CHANGE IN MUZZLE VELOCITY VARIATION(9)

12. SECOND LOT INFERRED FIRING UNIT MUZZLEVELOCITY VARIATION

13. SECOND LOT STANDARD MUZZLE VELOCITY

4- - -4 ----1 I- I14. SECOND LOT CALIBRATED MUZZLE

VELOCITY

15. SECOND LOT PIECE MUZZLE VELOCITYVARIATION

DA FORM 4982-R SEP84EDITION OF MAY 1981 IS OBSOLETE.

- -=I -I I



M90 VELOCIMETER WORK SHEETFor use of this form. see FM 6-40; the proponent agency is TRADOC.

ROJECTILE MODEL

PROJECTILE/FAMILY

PROJECTILE WEIGHT

-ITEMS

a

1. WEAPON BUMPER NUMBER

2. WEAPON TUBE NUMBER

Cl

Pi

4. ENDING POWDER TEMPERATURE

5. AVERAGE POWDER TEMPERATURE

ROUND 1

ROUND 2

ROUND 3

ROUND 4

ROUND 5

ROUND 6

ROUND 7

ROUND 8

READOUT AVERAGE

6. MUZZLE VELOCITY CORRECTION

FOR NONSTANDARD CONDITIONS

7. CALIBRATED MUZZLE VELOCITY

8. NUMBER OF WARMUPROUNDS FIRED

REMARKS

M90 VELOCIMETER READOUT

IAFORM 4982-1-R SEP84

EDITION OF MAY 1981 IS OBSOLETE

C

II

HARGE GROUP

3. STARTING POWDER TEMPERATURE

I ATE/TIME

t'U-rN U it i i ID~fl

.M

I II I

I II

II

EDITION OF MAY 1981 IS OSSOLETE.

I DATE/TIME

I POWDER LOI NUMt5t:h

DA FORM 4982-1 -R SEP 84



FM 6-40

APPENDIX K

GUNNERY TEAM PROCEDURES USING THEGROUND/VEHICULAR LASER

LOCATOR DESIGNATOR

K-1. SELF-LOCATIONa. An observer equipped with th e

ground/vehicular laser locator designator(G/VLLD operator) can use its distance-,direction-, and azimuth-determiningcapability to locate himself. In thisprocedure, he uses the G/VLLD to determine

the direction, distance, and vertical angle totwo known points separated by at least 150mils and preferably more than 300 mils.Normally the G/VLLD will be used with theFIST DMD for self-location. In staticsituations, the FDC may locate the G/VLLDposition on the firing chart (by resection) byconstructing an arc with a radius of thereported distance from each prearrangedpoint in the general direction of the backazimuth to the points. The intersection of thearcs is the G/VLLD location. The separationof the prearranged points ensures that the

arcs will intersect at a distinct point. Afterdetermining the G/VLLD location, the FDCmeasures the correct orienting azimuth to oneof the prearranged points. The location andazimuth are then sent to the G/VLLDoperator through secure means. The FDCmay also use the hand-held calculator.

CADDO

DIRECTIONDISTANCE

VERTICAL ANGLE

b. Location of the G/VLLD by the FDCcan be done by use of two known points, oneknown point and one burst, or two bursts.

K-2. LOCATION OF THEG/VLLD BY USE OFTWO KNOWN POINTS

a. The G/VLLD operator uses two knownpoints as the prearranged points (fig K-i).Known points may be established by survey,firing, or measuring from a map. The twoknown points method is used when the FISTDMD is not available. When measuring froma map, two techniques can be used.

(1) The G/VLLD operator can provideeight-place grids to the known points.

(2) The G/VLLD operator can give theFDC the general location (six-place grid) anddescription of the known point. Then the FDCdetermines an accurate location (eight-placegrid) through map/terrain analysis by use ofa map and a coordinate scale.

b. Once the known point locations havebeen established by the FDC, the operator

I

z\OP R TORDIRECTIONDISTANCEVERTICAL ANGLE

62381570

-8

Figure K-1. Location by use of two known points.

K-1

,,FLATTOP

50571230

-10



FM 6-40

reports G/VLLD polar plot data to the FDCfor each of the known points.

Note . All numerical values in thefollowing examples are encoded.

EXAMPLE:

T2A42 THIS IS B6H23, SELF-LOCATION, OVER.KNOWN POINT FLATTOP, DIREC-TION 6238, DISTANCE 1570, VERTI-CAL ANGLE -8, OVER.KNOWN POINT CADDO, DIRECTION5057, DISTANCE 1230, VERTICALANGLE -10, OVER.

c. The FDC determines the location oftheG/VLLD as follows:

(1) On a firing chart, the chart operatorconstructs an arc from each known point byuse of an RDP at the distance reported by theG/VLLD operator. The arc is centered alongthe back azimuth of the G/VLLD operator'sreported direction to the known point. Theintersection of the two arcs is the G/VLLDlocation.

Note . The G/VLLD locationcan befurther refined by taking the reported

distance and vertical angle of each knownpoint and computing he G/ VLLD operator'sknown point VI by use of a GST (chap 9).Each VI can then be applied to its knownpoint altitude to determine the G/VLLDoperator's altitude. The altitude of the arcintersection is then compared with thecomputed G/VLLD operator's altitude. If

there is a difference, the determinedG/VLLD location may be adjusted along heazimuth, midway between the azimuths ofthe two known points to a point where themap altitude matches the computedG/VLLD operator's altitude. Only minor

adjustments should be needed, if any.

(2) The chart operator measures thecorrect azimuth to one of the known pointsfrom the plotted G/VLLD location.

(3) The FDC encodes and sends theG/VLLD operator his location (eight-placegrid) and his direction to the known point.

EXAMPLE:

T2A54 THIS IS B6L54, LOCATION4725 3824, DIRECTION TO CADDO5039, OVER.

(4) From a map, the FDC determinesthe altitude of the G/VLLD operator'slocation if not already determined.

(5) The FDC records the G/VLLDoperator's location and altitude and storesthem in the FDC ballistic computer. Locationby use of two known points is the mostaccurate method of locating a G/VLLD.

K-3. LOCATION OF THEG/VLLD BY USE OFONE KNOWN POINTAND ONE BURST

a. If only one known point is available tothe G/VLLD operator, he may request that around (HE or WP) be fired to establish thesecond known point (fig K-2). The G/VLLD

CADDO

DIRECTION 1743+B4

DISTANCE 3180 00,VERTICAL ANGLE +10 3 M

I 300 MILS

' DIRECTION 2105DISTANCE 3420LI VERTICAL ANGLE 2

Figure K-2. Location by use of one known point and one burst.

K-2



FM 6-40

operator will provide the location for theround to burst. Graze bursts should be used.

EXAMPLE:

Observer sends to the FDC-T2A42 THIS IS K3M47, SELF-LOCATION, 1 ROUND, OVER.

KNOWN POINT CADDO, DIRECTION1743, DISTANCE 3180, VERTICALANGLE +10, OVER.

1 ROUND GRID 598360, OVER.(round fired and observed)

DIRECTION 2105, DISTANCE 3420,VERTICAL ANGLE -12, OVER.

b. The procedures used by the FDC todetermine the location of the G/VLLD are thesame as those used for two known points. Thegrid of the burst location is reported by theG/VLLD operator and is used instead of thesecond known point. The vertical anglereported to the one known point can be used tofurther refine the G/VLLD location. Thedetermined G/VLLD location can beadjusted along the azimuth to the knownpoint to a point where the map altitudematches the computed G/VLLD operator's

altitude.

K-4. LOCATION OF THEG/VLLD BY USE OFTWO BURSTS

a. When no known points are available tothe G/VLLD operator, he may request that

two rounds be fired to establish the knownpoints (fig K-3). Graze bursts should be used.

EXAMPLE:

T2A24 THIS IS T2A58, SELF-

LOCATION, 2 ROUNDS, OVER.1 ROUND, GRID 603368, OVER.(round fired and observed)

DIRECTION 6398, DISTANCE 4110,VERTICAL ANGLE -9, 1 ROUND,GRID 564381, OVER.(round fired and observed)

DIRECTION 5927, DISTANCE 3840,VERTICAL ANGLE -11, OVER.

b. The procedures used by the FDC todetermine the G/VLLD location are the sameas those used for the two methods previouslydescribed. After determining the G/VLLDlocation, the FDC measures the azimuth tothe second burst. The determined G/VLLDlocation and azimuth are sent to the G/VLLDoperator.

EXAMPLE:

T2A58 THIS IS T2A24, LOCATION58723 34231, DIRECTION TO SEC-OND ROUND 5918. OVER.

c. Self-location by use of two bursts is theleast accurate method, because accuracydepends on the accuracy of the firing databeing used. This method is not recommendedunless current registration corrections oraccurate muzzle velocities, battery location,and met are available.

LX OPERATOR

Figure K-3. Location by use of two bursts.

K-3

DIRECTION 5927DIRECTION 6398 DISTANCE 3840DISTANCE 4110 VERTICAL ANGLE

-11

VERTICAL ANGLE -9 7



FM 6-40

K-5. G/VLLD LOCATION BYUSE OF FADAC/BCS

The reported self-location data can beprocessed by use of the SURVEY (E4)function in the FADAC or BCS SPRTlocation routines.

K-6. SECOND G/VLLDOPERATORASSISTANCE

An operator emplacing a G/VLLD mayhave no known points in his area (fig K-4).Rather than accept the inherent inaccuraciesof self-location by use of two bursts, the FDCmay recommend that the G/VLLD operatorcontact a nearby operator that has anaccurately located G/VLLD and have himestablish some known points in the area ofthe G/VLLD being located. Both G/VLLDoperators must be able to see a common areawell enough to clearly identify and locateprominent objects that can serve as knownpoints. Once agreeable points have beenidentified, they can be established as knownpoints as in figure K-4.

Figure K-4. Second G/VLLD operatorassistance.

EXAMPLE:

A G/VLLD operator (T2A23) has noknown points in his area. The FDC (B6H16)instructs him to.contact a nearby G/VLLDoperator having an accurately

locatedG/VLLD (T2A47) for assistance inestablishing known points, in his area.Acceptable points have been identified. Theyare sent to the FDC as known points.

B6H16, THIS IS T2A47, KNOWNPOINTS FOR T2A23, OVER.

KNOWN POINT TREE, DIRECTION0832, DISTANCE 5740, VERTICALANGLE -9, OVER.

KNOWN POINT TANK BODY, DIREC-TION 0947, DISTANCE, 6370,VERTICAL ANGLE -11, OVER.

The FDC plots the known point locations.T2A23 initiates self-location by use of twoknown points.

B6H16, THIS IS T2A23, SELF-LOCATION, OVER.

KNOWN POINT TREE, DIRECTION5823, DISTANCE 6240, VERTICALANGLE -10, KNOWN POINT TANKBODY, DIRECTION 6207, DISTANCE5970, VERTICAL ANGLE -14, OVER.

T2A23, THIS IS B6H16, LOCATION3837 4512, DIRECTION TO TREE5818, OVER.

Note. All transmissions should be madeon the same communications net so that allthree stations can monitor the informationbeing passed.

K-7. LOCATION BYSIMULTANEOUSOBSERVATION

a. During periods of limited visibility, aG/VLLD operator with an accurately locatedG/VLLD can help determine the location ofanother G/VLLD by performing simultane-ous observation with the other G/VLLDoperator on two illumination rounds. BothG/VLLD operators must be able to see and

K-4

I



FM 6-40

lase the flares (fig K-5). The operator with theaccurately located G/VLLD acts as thecontrolling station and initiates the call forfire.

(- LLUMNATON ROUNDS

SIMULTANEOUS SIMULTANEOUSi/"/OBSERVATION OBSERVATION -SECOND FIRST

I-ROUND ROUND

30 0

I \ MILS

SURVEYEDOBSERVATION POST

OBSERVATION POSTLOCATION UNKNOWN

U U

Figure K-5. Location by simultaneousobservation.

EXAMPLE:

T2A47 is the operator of the accuratelylocated G/VLLD. T2A23 is the operator ofthe G/VLLD being located. B6H16 is thebattery fire direction center. Coordinationbetween T2A47 and T2A23 has already beenaccomplished.

B6H16 THIS IS T2A47, SIMULTANE-OUS OBSERVATION WITH T2A23,OVER.

1 ROUND, GRID 374522, 1 ROUND,GRID 391516, OVER.

ILLUMINATION, BY ROUND AT MY

COMMAND, OVER.T2A47, THIS IS T2A23, READY TOOBSERVE, OVER.

T2A47, THIS IS T2A16, READY,OVER.

b. As each illumination round is fired, theoperator with the accurately locatedG/VLLD coordinates simultaneous lasing ofthe flares. Both operators lase each flaresimultaneously and send the data to the firedirection center.

EXAMPLE:

B6H16, THIS IS T2A47, DIRECTION0437, DISTANCE 3780, VERTICALANGLE +21, OVER.

B6H16, THIS IS T2A23, DIRECTION6377, DISTANCE 4120, VERTICALANGLE +23, OVER.

c. When observation data for both roundshave been obtained, the FDC determines thelocation of the previously unlocatedG/VLLD. This is done by using the polar plotdata from the accurately located G/VLLDand placing a plotting pin at the location ofeach illumination round at the time of lasing.These pin locations are used as known points.The location of the unlocated G/VLLD isthen determined by using the sameprocedures used by the FDC for self-locationby use of two known points. After theG/VLLD location has been determined, theazimuth to the pin location representing thesecond illumination round is measured. Theresulting information is sent to the operatorof the newly located G/VLLD.

EXAMPLE:

T2A23 THIS IS H6E26, LOCATION9164 3842, DIRECTION TO SECONDROUND 0317, OVER.

K-8. OPERATOR CLOUDHEIGHT

In addition to his location, the G/VLLDoperator reports the height of the clouds overhis position (operator cloud height) to thebattery FDC supporting him (fig K-6). This

Figure K-6. Determining operator cloud height.

K-5



FM 6-40

Table K-1. G/VLLD operator cloud height.

RANGE 0 100 200 300 4001500 510 540 570 610 640'2000 670 710 740 780 102500 840 880 910 940' 9803000 1010 1040 1080 1110 11403500 1180 1210 1250 1280 13104000 1350 1380 1420 1450 14804500 1520 1550 1580 1620 16505000 1680 1720 1750, 1790 18205500 1850 1890 1920 1950 19906000 2020 2060 2090 2120

Notes.7. A similar table is on the cover of the Copperhead footprint templates. The operator shouldreport operator cloud.height as soon as possible after occupying a position. He then reportschanges only when the change in operator cloud height exceeds 100 meters.2. An increase or decrease of 300 meters in measured slant range corresponds to an approx-imate 700-meter increase or decrease in cloud height.3. Enter table with range to nearest 100 meters (interpolation required).

information is essential for computing firingdata for Copperhead. The reported operatorcloud height is recorded by the supportingbattery FDC, which forwards th e

information to the battalion FDC. 'TheG/VLLD operator updates his reportedoperator cloud height when the measuredchange in height is 100 meters or greater.Cloud height is measured by setting a verticalangle of +350mils on the G/VLLD and lasingthe distance to the cloud cover. The cloudheight table (table K-i) is used to convert thedistance to the cloud height.

K-9. ADJUSTMENT OF FIREa. With the G/VLLD located and

oriented, the resulting target locations areaccurate enough for first round fire for effect.However, some of the other requirements foraccurately predicted fire may be lacking.When the G/VLLD operator is in doubt as towhether he can achieve first round FFE onthe target, an adjust fire mission is requested.When the first round impacts, the G/VLLDoperator determines the angular deviation by

determining the difference between themeasured direction to the target and themeasured direction to the burst of theadjusting round (fig K-7).

b. If the angular deviation is greater than100 mils, the mil relation and operatoradjustment techniques do not provideaccurate adjustments. In this case, theG/VLLD operator sends the laser polar plotdata of the burst to the FDC to compute theshift.

EXAMPLE:

BURST DIRECTION 5872, DISTANCE4350, VERTICAL ANGLE -11, FIREFOR EFFECT, OVER.

The manual FDC computes the shift by usingthe M17 plotting board. The FDC orients theplotting board on the OT direction given inthe call for fire and plots the target at the OTdistance measured with the G/VLLD. TheG/VLLD operator sends the FDC thedirection, distance, and vertical angle to theadjusting round. The FDC orients' theplotting board on the operator-burst (OB)

K-6



FM 6-40

direction and plots the burst at the distancemeasured with the G/VLLD. The FDCreorients the plotting board on the OTdirection and determines the lateral andrange shifts required to move the burst of theadjusting round to the target. The accuracy issufficient to permit fire for effect on the targetfollowing a large shift from the initialadjusting point.

c. If no plotting board is available, sineand cosine functions can be used to determinethe correct shift. Rough sine functions fromthe TFT or from TM 6-230 are used. See theintroduction of TM 6-230 for explanation ofits use. Angular values can also bedetermined by use of the hand-heldcalculator.

K-10. AUXILIARY AIMINGPOINT

a. To achieve surprise on a target whenFFE is not possible, the auxiliary aimingpoint method may be used. This method

identifies an adjusting point that will placean adjusting round 100 to 300 mils away fromthe intended target.

EXAMPLE:

B6H16, THIS IS T2A23, ADJUST FIRE,

SHIFT AUXILIARY ADJUSTINGPOINT, OVER.

TARGET DIRECTION 220, DISTANCE3680, VERTICAL ANGLE +2, OVER.

ADJUSTING POINT GRID 633374,OVER.BATTALION ASSEMBLY AREA, ICMIN EFFECT, OVER.

b. When the adjusting round bursts, theG/VLLD operator lases the burst and sendsthe data to the FDC (fig K-8). The FD C

determines the shift required to move theburst to the auxiliary adjusting point. Thatshift is applied to the target location, definingthe target aiming point location.Fire-for-effect data are then computed at thetarget aiming point.

Figure K-7. Use of the G/VLLD to determine subsequent corrections.

Figure K-8. Adjust fire from auxiliary aiming point.

K-7



FM 6-40

K-11. REGISTRATIONSa. High-Burst or Mean-Point-of-

Impact Registration. The G/VLLD maybe used to conduct an HB/MPI registration.Orienting data are provided by the FDC, andone G/VLLD-equipped observer is required.He determines the direction, distance, andvertical angle for each burst and provides theround-by-round data to the FDC. The FD Cdetermines the average direction, distance,and vertical angle to the high burst. Usingthese averages, the FDC determines thelocation of the HB/MPI and registration

corrections as in a normal HB registration.The G/VLLD must be accurately located andoriented before this technique can be used.

CAUTION:Safety res t r ic t ions intraining may prevent lasing a high burstif it is above the skyline. Lasing abovethe skyline requires permission from

range control.

b. Precision Registrat ion. In theconduct of a precision registration, theoperator uses the G/VLLD to determinecorrections as described in the procedures forusing the G/VLLD in the adjustment of fire.When the adjusting round is brought within50 meters of the

registration point (100 meterswhen the probable error in range is 25 metersor more), the adjustment procedures fornormal precision fire are used. Precisionregistrations should be conducted only whenthe G/VLLD has not been accurately located.

K-12. ABBREVIATEDREGISTRATIONTECHNIQUES

The tactical situation or ammunitionconstraints may

prohibit conducting afull-scale HB/MPI or precision registration.

In an abbreviated registration; the G/VLLDoperator lases the burst of the first adjustinground and determines corrections in the samemanner as for the adjustment of fire by use ofthe G/VLLD. The FDC computes the data forthe second round and fires it. The G/VLLDoperator lases the second burst and reportsthe corrections. The FDC determinesadjusted data. These adjusted data are notfired. Registration data are based on the dataobtained on the two adjusting rounds. If atime registration has also been requested, twoairbursts are obtained to establish the meanheight of burst. The operator sendscorrections to adjust the mean height of burstto 20 meters.

EXAMPLE:T2A23, THIS IS B6H26, ABBREVI-ATED REGISTRATION, REGISTRA-TION POINT 1, QUICK AND TIME,OVER.B6H26, THIS IS T2A23, DIRECTION6216, OVER.(First adjusting round is fired. Angle ofdeviation is greater than 100 mils.)DIRECTION 6327, DISTANCE 5430,VERTICAL ANGLE -11, OVER.(Data are computed and

second adjustinground is fired. Angle of deviation is less than100 mils.)

LEFT 30, ADD 50, RECORD ASREGISTRATION POINT 1, TIME,REPEAT, OVER.(Adjusted deflection and elevation aredetermined. Data or fuze time are computed.One HE round at a time is fired with fuzetime until an airburst is obtained. Then twoHE/time rounds are fired.)DOWN 25, RECORD AS TIME REGIS-TRATION POINT 1, END OF MISSION.(Adjusted time is determined.)

K-8



FM 6-40.

GLOSSARY

DEFINITIONS OF COMMON TERMS

A

ablation-the loss of surface material by burning or

charring caused by the friction of a fluidmoving past an object at high speedand/or temperature. The effect is used toadvantage in cooling high-speed bodiessuch as ballistic missile warhead sectionsor other space reentry vehicles.

ADD-a correction reported by an observer or a

spotter to indicate that an increase in rangealong the observer- target line is desired.

ADJUST-an order to the observer or spotter to initiate

an adjustment on a designated target.

adjusted elevation-elevation based on firing and computed to

place the center of impact at a given orknown range.

ADJUST FIRE-an order or request to initiate an

adjustment.-a method of control transmitted in the call

for fire by the observer or the spotter toindicate that he will control theadjustment.

adjustment-a process used in artillery and naval

gunfire to obtain the correct direction,range, and height of burst (if time fuzes are

used) inengaging a target by observed fire.

AIR-a spotting or an observation by a spotter or

an observer to indicate that a burst or groupof bursts occurred before impact (also seegraze).

airburst-an explosion of a bomb or projectile above

the surface as distinguished from anexplosion on contact with the surface orafter penetration of the surface.

-the explosion of a nuclear weapon in the airat a height of burst greater than themaximum radius of the fireball.

ammunition lot number-the code number that identifies a particular

quant i ty of ammunit ion from onemanufacturer. The number is assigned to

each lot of ammunition when it is

manufactured.

angle of departure-in artillery, the vertical angle between the

tangent to the trajectory at the origin andthe horizontal or base of the trajectory.

angle of fall-the vertical angle between the tangent to

the trajectory at the level point and thelevel base of the trajectory.

angle of site

-the vertical angle between the level base of

the trajectory/horizontal and the line ofsite.

angle T-the angle formed at the target by the

intersection of the gun-target line and theobserver-target line.

AT MY COMMAND-the command used to indicate desire to

control the exact time of delivery of fire.

axis of tube-the straight line through the center of the

bore at the breech end and the center of thebore at the muzzle end.

B

ballistic density-the computed constant air density that

would have the same total effect on aprojectile during its flight as the varyingdensities actually encountered.

ballistics-the science or art that deals with motion,

behavior, appearance, or modification of

Glossary-1



FM 6-40

missiles or other vehicles acted upon bypropellants, wind, gravity, temperature, or

-any other modifying substance, condition,or force.

barrel-a metal or plastic tube through which

ammunition is fired and which controls theinitial direction of the projectile.

-a standard unit of measure of liquids inpe t ro leum pipel ine and s to rageoperations-42 US standard gallons.

barrel erosion-the wearing away of the inner surface of

the bore due to the combined effects ofgas, washing, scoring, and mechanicalabrasion. Barrel erosion causes a reductionin muzzle velocity.

base of trajectory-a line extending from the muzzle of the tube

that intersects the trajectory at the samealtitude as the muzzle.

BATTERY ADJUST-a command given to alert all pieces of the

battery.

battery center-a point materialized on the ground at the

approximate geometric center of thebattery position; the chart location of thebattery.

battery front-the lateral distance between the flank guns

of a battery.

battery (troop) left (right)-a method of fire in which weapons are

discharged from the left (right), one afterthe other, at 5-second intervals.

BATTERY 1 (or more) ROUND-a method of fire announced as a fire

command that directs that all pieces befired

at the same time.beehive (ammunition)-a type of ammunition designed for use in

defending a position against massedpersonnel attacks.

boat tail-the conical section of a ballistic body that

progressively decreases in diameter towardthe tail to reduce overall aerodynamic drag.

boost cutoff-the point in a trajectory of a rocket or

missile at which the boost phaseterminates.

bracketing

-a method of adjusting fire in which abracket is established by obtaining anOVER and a SHORT along the spottingline and then successively splitting thebracket in half until a TARGET HIT ordesired bracket is obtained.

breechblock-a movable steel block that closes the breech

of a cannon.

breech ring-the breechblock housing, screwed or

shrunk onto the rear of a cannon tube, inwhich the breechblock engages.

burster-an explosive charge used to break open and

spread the contents of chemical projectiles,bombs, or mines.

Ccaliber-the diameter of the bore of a gun. In rifled

gun barrels, the caliber is obtained bymeasuring between opposite lands. Acaliber .45 revolver

has a barrel with a landdiameter of 45/100 of an inch.-the diameter of a projectile.-a unit of measure used to express the length

of the bore of the weapon. The number ofcalibers is determined by dividing thelength of the bore of the weapon, from thebreech face of the tube to the muzzle, by thediameter of its bore. A gun tube with thebore 40 feet (480 inches) long and 12 inchesin diameter is said to be 40 calibers long.

call for fire

-- a request for fire containing data necessaryfor obtaining the required fire on a target.

cancel-when coupled with an order other than

quantity or type of ammunition, rescindsthat order.

cannon-a complete assembly consisting of an

artillery tube, a breech mechanism, a firing

Glossary-2



FM 6-40

mechanism, and a sighting system

mounted on a carriage.

cannoneer-a member of an artillery gun or howitzer

crew whose primary duty is servicing the

piece.cannot observe-a type of fire control which indicates that

the observer or spotter will be unable to

adjust fire but believes a target exists at thegiven location and is of sufficient

importance to justify firing on it withoutadjustment or observation.

centrifugal force-the force acting on a rotating body that

tends to move its parts outward and away

from the center of rotation.

charge-the propellant of semifixed or separate-

loading ammunition.

CHECK FIRING-a command used to cause a temporary halt

in firing.

chemical agent-a chemical compound which, when

su i t ab ly d i s semina t ed , produces

incapacitating, lethal, or damaging effects

on men, animals, plants, or materials.

circular error probable-an indicator of the accuracy of a missile

(projectile) used as a factor in determiningprobable damage to a target. It is the radiusof a circle within which half the missiles(projectiles) are expected to fall.

complementary angle of site (comp site)-the correction to compensate for the error

made in assuming rigidity of the trajectory.

complementary range (comp range)

-range corrections corresponding to the

complementary angle of site. These rangecorrections are tabulated in the firingtables and are a function of chart range andheight above (below) the gun.

complete round-a term applied to an assemblage of

explosive and nonexplosive componentsdesigned to perform a specific function at

the time and under the conditions desired.Examples of complete rounds of

ammunit ion are s e p a r a t e . loading,

consisting of a primer, a propelling charge,and, except for blank ammunition, aprojectile and a fuze; and fixed or

semifixed, consisting of a primer, apropelling charge, a cartridge case, aprojectile, and, except when a solidprojectile is used, a fuze.

computer-a mechanical or electromechanical

instrument used to solve mathematicalproblems. It is used to obtain data for

artillery and for navigation. A computerused with air defense artillery receivescontinuous present-position data onaircraft or other moving targets andcontinuously calculates firing data for useagainst such targets; data computer.

-a fire direction center operator whocomputes data for laying and firingartillery guns.

continuous fires-fire conducted at a normal rate without

interruption for applying adjustmentcorrections.

-in field artillery and naval gunfire, loadingand firing as rapidly as possible, consistentwith accuracy, within the prescribed rate of

fire for the weapon. Firing will continueuntil the command CHECK FIRING,CEASE LOADING, or END OFMISSION is given.

continuous illumination-a type of fire in which illuminating

projectiles are fired at specified timeintervals to provide uninterrupted lightingon the target or specified area.

CONVERGE-a request or command used in a call for fire

to indicate that the observer or spotterdesires a sheaf in which the planes of fireintersect at a point.

converged sheaf-a type of sheaf in which each gun fires at a

unique time, deflection, and quadrantelevation to cause the rounds to impact at

the same point.

cook off-the functioning of a chambered round of

ammunition initiated by the heat of the

weapon.

Glossary-3



FM 6-40

coordinated illumination-the firing of illuminating rounds to

illuminate a target and the surroundingarea only at the time required for spottingand adjusting high-explosive fire.

coppering-metal fouling left in the bore of a weapon bythe rotating band or jacket of a projectile.

Coriolis effect-the apparent change in range or azimuth

caused by the rotational effects of the earth.correction-any change in firing data to bring the mean

point of impact or burst closer to the target.-a communications proword to indicate that

an error in data has been announced andthat corrected data will follow.

crest-a terrain feature of such altitude that itrestricts fire or observation in the areabeyond, resulting in dead space, limitationof the minimum elevation, or both.

CRESTED-- a report that indicates that engagement ofa target or observation of an area is notpossible because of an obstacle orintervening crest.

deflection-the setting on the scale of the sight of aweapon to place the line of fire in the

desired direction.-the horizontal clockwise angle between the

axis of the tube and the line of sight.

deflection index-a fine line constructed on the firing chart

and used to measure deflection with therange-deflection protractor.

deflection limits-right and left traverse limits that establishhe lateral limits of a designated impactarea.

deflection probable error-- the directional error caused by dispersion

that will be exceeded as often as not in aninfinite number of rounds fired at a singledeflection. It is one eighth the width of the

dispersion pattern at its greatest width.This value is given in the firing tables.

delay action-the predetermined delayed explosion of an

ammunition item after activation of thefuze.

description of target-an element in the call for fire in which theobserver or spotter describes theinstallation, personnel, equipment, oractivity to be taken under fire.

destruction fire-fire delivered for the sole purpose of

destroying materiel objects.

deviation-the distance by which a point of impact orburst

misses the target.-the angular difference between magneticand compass headings.

direction-a term used by a spotter or an observer in acall for fire to indicate the bearing of the

spotting line.

dispersion pattern-the dispersion of a series of rounds fired

from one weapon or a group of weaponsunder conditions as nearly identical aspossible.

The points of bursts or impactsare dispersed about a point called the meanpoint of impact.

dispersion rectangle-a table that shows the probable

distribution of a succession of shots firedwith the same firing data. A dispersionrectangle consists of a diagram made up of64 zones. The table shows the percentage ofshots that may be expected to fall withineach zone.

doubtful-a term used by the observer or spotter to

indicate that he was unable to determinethe difference in range between the targetand a round or rounds.

DOWN-a term transmitted in a call for fire toindicate that the target is at a lower altitude

than the reference point used in identifyingthe target.

Glossary-4

S



FM 6-40

-a correction reported by an observer or aspotter in time fire to indicate that adecrease in height of burst is desired.

drag-the resistance of the atmosphere to the

movementof a projectile through it. Drag is

directly proportional to the diameter andvelocity of the projectile and the density ofthe air.

drift-the lateral deviation of the trajectory from

the plane of departure caused by therotation of the projectile. As a result of thedeviation, the horizontal projection of thetrajectory would be a curved line ratherthan a straight line. The deviation isalways to the right with a projectile havinga right-hand spin.

DROP-a correction reported by an observer or a

spotter to indicate that a decrease in rangealong the observer-target line is desired.

E

elevate-to raise the muzzle or warhead end of a

weapon.

elevation-the vertical angle between horizontal and

the axis of the bore or rail of a weaponrequired for a projectile to reach aprescribed range.

emplacement-a prepared position for one or more

weapons or pieces of equipment for thepurpose of protection against hostile fire orbombardment.

-the act of fixing a gun in a preparedposition from which it may be fired.

END OF MISSION-an order given to terminate firing...on aspecific target.

ephemeris-a tabular statement of the assigned places

of celestial bodies for regular intervals.

exterior ballistics-- a subdivision of ballistics that deals with

the phenomena associated with th e

aerodynamic performance of missiles.

Ffinal protective fire-an immediately available, prearranged

barrier of fire designed to impede enemymovement across defensive lines or areas.

fins-aerodynamic surfaces externally attachedto a missile or projectile designed to providestability and control during flight.

FIRE-the command given to discharge a weapon.

fire control-all operations connected with the planning,

preparation, and actual application of fireon a target.

fire direction

-the tactical employment of firepower. Theexercise of tactical command of one or moreunits in the selection of targets, theconcentration or distribution of fire, andthe allocation of ammunition for eachmission. Fire direction also includes themethods and techniques used in firedirection centers to convert targetin format ion into appropr ia te firecommands.

fire direction center

-the element of a command post consisting

of gunnery and communications personneland equipment by means of which thecommander exercises fire direction and/orfire control. The fire direction centerreceives target intelligence and requests forfire and translates them into appropriatefire direction.

FIRE FOR EFFECT-a command to indicate that fire for effect is

desired.

fire for effect

-fire that is intended to achieve a desiredeffect on the target.

FIRE MISSION--an order used to alert the battery area and

to indicate that the message following is acall for fire.

fire mission--a specific assignment given to a fire unit as

part of a definite plan.

Glossary-5



FM 6-40

firing data-all data necessary for firing an artillery

piece at a given objective. Such data may bedetermined by computation and thentransmitted by verbal commands or may beapplied electromechanically by one of the

several types of directing devices.firing table-a table or chart giving the data needed for

firing a weapon accurately on a targetunder standard conditions. It also gives thecorrections that must be made for specialconditions such as winds or variations oftemperature.

fixed ammunition-ammunition in which the cartridge case is

permanently attached to the projectile.

FUZE-a command or request to indicate the typeof fuze action desired; for example, delay,quick, time, or VT.

fuze-a device used in munitions to initiate a

detonation.fuze delay-a fuze that has a delay element

incorporated into the fuze train.

fuze super quick-a fuze

that functions immediately uponimpact of the projectile with the target.Action of this type of fuze is the quickestpossible. The firing pin is driven into theprimer immediately upon first contact ofthe missile with the target; hence, themissile functions at the surface of thetarget. Also called instantaneous fuze.

fuze time-(fuze mechanical time super quick) a fuze

that contains a graduated time element toregulate the time interval after which thefuze will function.

fuze VT-see proximity fuze.

GRAZE-a spotting or observation reported by a

spotter or an observer to indicate that allbursts occurred on impact.

grid-a term used when giving the location of a

geographic point by grid coordinates.-two sets of parallel lines intersecting at

right angles and forming squares. The gridis superimposed on maps,

charts, and othersimilar representations of the earth'ssurface in an accurate and consistentmanner to permit identification of groundlocations with respect to other locationsand to permit the computation of directionand distance to other points.

grid convergence-the angular difference in direction between

grid north and true north. It is measuredeast or west from true north.

grid coordinates

-numbers and letters of a coordinate systemthat designate a point on a gridded map,photograph, or chart.

grid line-one of the lines in a grid system; the line

used to divide a map into squares.East-west lines in a grid system are X lines,and north-south lines are Y lines.

grid magnetic angle-the angular difference in direction betweengrid north and magnetic north. It is

measured east or west from grid north. Gridmagnetic angle is sometimes calledgrivation and/or grid variation.

grid north-the northerly or zero direction indicated by

the grid datum of direction reference.

grid system-imaginary lines dividing the earth into

sectors to aid in the location of points.

gun-target line-an imaginary straight line from the gun to

the target.

height of burst-the vertical distance from the earth's

surface or the target to the point of burst.-for nuclear weapons, the optimum height of

burst for a particular target (or area) atwhich it is estimated a weapon of aspecified energy yield will produce a certaindesired effect over the maximum possiblearea.

Glossary-6



FM 6-40

HIGH ANGLE-an order or request to obtain high-angle

fire.

high-angle fire-fire delivered at elevations greater than the

elevation of maximum range. The range offire decreases as the angle of elevationincreases. Mortars deliver high-angle fire.

high-order detonation-complete and instantaneous explosion.

I

index-a scribed mark on an instrument indicating

the number to be read.

indirect fire-fire delivered at a target that cannot be seenby the aimer.

-fire delivered on a target that is not used asa point of aim for the weapon or thedirector.

interior ballistics-a subdivision of ballistics that deals with

the phenomena associated with impartingkinetic energy to missiles.

intermediate crest

-a crest lyingbetween the firing point and

the forward line of own troops (FLOT) thatis not visible from the firing point. Theminimum quadrant elevation to clear thiscrest is the intermediate crest minimumquadrant elevation.

L

lands-the raised portion between the grooves in

the bore of a gun. Spiral channels cut in the

bore of a gunare called grooves.

lateral spread-a technique used to place the mean point of

impact of two or more units 100 metersapart on a line perpendicular to the

gun-target line.

lay--to direct or adjust the aim of a weapon.

-the setting of a weapon for a given range orfor a given deflection or for both.

level point-the point on the descending branch of the

trajectory that is at the same altitude as the

point of origin. The point at which thetrajectory cuts the base. It is sometimesreferred to as point of fall.

LINE-a spotting or an observation reported by a

spotter or an observer to indicate that aburst occurred on the spotting line.

line of departure-a line designated to coordinate the

departure of attack or scouting elements; ajump-off line.

line of elevation-the axis of the bore prolonged.

line of fall

-the line tangent to the trajectory at the levelpoint.

line of sight-line of vision.

-the straight line between two radio

antennas.

line of site-a straight line joining the origin and a

point, usually the target.

LOST

-a spotting or an observation reported by aspotter or an observer to indicate thatrounds fired by a gun or mortar were notobserved.

low-angle fire-fire delivered at angles of elevation at or

below the elevation that corresponds to them a x i m u m r a n g e of the gun andammunition concerned.

M

maximum ordinate-the highest point along the trajectory of a

projectile. The difference in altitude(vertical interval) between the origin andthe summit.

maximum quadrant elevation-the greatest vertical angle at which an

artillery piece can be laid. The angle is

limited generally by the mechanicalstructure of the piece.

Glossary-7



FM 6-40

mean height of burst-the average of the heights of burst of a

group of rounds fired with the same firingdata.

mean point of impact-the point whose coordinates are the

arithmetic mean of the coordinates of theseparate points of impact of a finite numberof projectiles fired or released at the sameaiming point under a given set ofconditions.

mechanical time fuze-a fuze with a clocklike mechanism that

controls the time at which the fuze willfunction.

meteorological data-meteorological facts pertaining to the

atmospheresuch as wind, temperature, airdensity, and other phenomena which affect

military operations.

meteorological datum plane-the reference plane assumed as a basis or

starting point for atmospheric datafurnished to artillery. Its altitude is that ofthe meteorological station.

mil-a unit of measure for angles based on the

angle subtended by 1/6400 of thecircumference of a circle. A mil is the angle

subtended by one unit at 1,000 units.-1/1000 of an inch (wire measurement).

mine action-the explosion of a shell below the surface of

the ground.

minimum quadrant elevation-the minimum vertical angle of the tube for a

specific charge which, when fired, willensure that the round impacts in thedesignated impact area.

minimum range-the least range setting of a gun at which the

projectile will clear an obstacle or friendlytroops between the gun and the target.--the shortest distance to which a gun canfire from a given position.

misfire-failure to fire or explode properly.-failure of a primer or the propellant of a

projectile to function wholly or in part.

-failure of the propellant to ignite when thefiring circuit is completed.

MIXED-a spotting or an observation reported by a

spotter or an observer to indicate that the

rounds fired resulted in an equal number ofairbursts and impact bursts.

MIXED AIR-- a spotting or an observation reported by a

spotter or an observer to indicate that therounds fired resulted in both airbursts andimpact bursts, with a majority of the burstsbeing airbursts.

MIXED GRAZE-a spotting or an observation reported by a

spotter or an observer to indicate that therounds fired resulted in both airbursts andimpact bursts, with a majority of the burstsbeing impact bursts.

muzzle velocity-the velocity of a projectile with respect to

the muzzle at the instant the projectileleaves the muzzle of the weapon.

muzzle velocity variation-the change in muzzle velocity of a weapon

from the s tandard muzzle velocityexpressed in meters per second.

northing-the northward (that is, from bottom to top)

reading of grid values on a map.

number of rounds-the number of projectiles per tube to be fired

on a specified target.

observation post-a pos i t ion from Which mil i ta ryobservations are made or fire directed andadjusted and which possesses appropriatecommunication. It may be airborne. Thepoint selected for the observation andcorrection of fire.

observer-target line-an imaginary straight line from th e

observer or the spotter to the target.

Glossary-8

i rTrwr.1.1 -imam"" MWWllM9%R .,m=MWfiTE'



FM 6-40

observer-target range-the distance along an imaginary straight

line from the observer or the spotter to thetarget.

obturation

-any process that.prevents the escape of

gases from the tube of a weapon during thefiring of a projectile.

ogive-the curved forward part up to and including

the pointed end of a projectile; also calledhead.

on-call targets-planned targets, other than scheduled

targets, on which fire is delivered whenrequested.

open sheaf-a type of sheaf in which each gun fires at aunique time, deflection, and quadrantelevation to cause the rounds to impact in astraight line, perpendicular to the GTazimuth and centered on the target, withbursts separated by one bursting radius.

origin of the trajectory-the center of the muzzle of a gun at the

instant the projectile leaves it.

OUT-(in conduct of fire procedures only)

indicates the end of a transmission, but thesame station is expected to transmit. It alsoindicates the termination of a read back.

-(in normal radiotelephone procedures otherthan conduct of fire) indicates that this isthe end of the transmission, and no answeris required or expected.

OVER-a spotting or an observation used by a

spotter or an observer to indicate that aburst has occurred beyond the target inrelation to the observer-target line.

-(for normal radiotelephone proceduresother than conduct of fire) indicates thatthis is the end of the transmission, and ananswer is expected.

P

point-detonating fuze-a fuze located in the nose of a projectile that

is initiated upon impact.

polar coordinates-the direction, distance, and vertical shift

from a known point to another point; forexample 6,200 mils, 300 meters, up 20 mils.

-consists' of the direction, distance, andvertical correction (shift) from the

observer'sposition to the target.

polar plot-the method of locating a target or a point on

the map by means of polar coordinates.

predicted fire-the term used to describe the ultimate

delivery technique of applying accuratelycomputed corrections (not determined byfiring) to standard firing data for allnonstandard conditions of the weather/weapon/ammunition combination and forthe rotation of the earth. It implies the

capability of delivering accurate surprisenonnuclear or nuclear fires on a target ofknown location in any direction from theweapon position and limited in range onlyby the characteristics of the weapon andammunition used.

probable error-the measurement of the impact distribution

in the dispersion pattern around the meanpoint of impact.

projectile-an object projected by an applied exterior

force and continuing in motion by virtue ofits own inertia such as a bullet, bomb, shell,or grenade. A term also applied to rockets

and to guided missiles.propellant-that which provides the energy required for

propelling a projectile. Specifically, anexplosive charge for propelling a bullet,shell, or the like. Also a fuel, either solid orliquid, for propelling a rocket, missile, orthe like.

propelling charge-a powder charge that is set off in a weapon

to propel a projectile from it; thepropellant. Burning of the confined propel-lant produces gases that force th eprojectile out.

propellant increment--a distinct portion of a propelling charge

designed to permit separation from thetotal charge for range-ad jus tmentpurposes.

Glossary-9



FM 6-40

proximity fuze-a fuze designed to detonate a projectile,

bomb, mine, or charge when activated byan external influence in the close vicinity ofa target. The variable time fuze is one typeof proximity fuze.

Qquadrant elevation-the angle between the level base of the

trajectory/horizontal and the axis of thebore when laid. It is the algebraic sum ofthe elevation, angle of site, an dcomplementary angle of site.

range-the distance between any given point and

an object or a target.-the extent or distance limiting the

operation or action of something such asthe range of an airplane, a vehicle, or a gun.

-the distance that can be covered over a hardsurface by a ground vehicle, with its ratedpayload, using the fuel in its tanks and incans normally carried as part of the groundvehicle equipment.

-an area equipped for practice in shooting attargets (also called target range).

range correction-a change in firing data necessary to allow

for deviation of range due to weather,ammunition, or other nonstandardconditions.

range-deflection protractor-a device used to measure range and

deflection.

range K-a correction expressed in meters per 1,000

meters range to correct for nonstandardconditions.

range probable error--the range error caused by dispersion that

will be exceeded as often as not in aninfinite number of rounds fired at the sameelevation. It is one eights the length of thedispersion pattern at its greatest length.The value is given in the firing tables.

range spread-the technique used to place the mean point

of impact of two or more units 100 metersapart on the gun-target line.

REPEAT

-an order or request to fire again the samenumber of rounds with the same method offire.

rotating band-the soft metal band around a projectile near

its base. The rotating band makes theprojectile fit tightly in the bore by centeringthe projectile, thus preventing the escape ofgas and giving the projectile its spin.

round-one shot fired by a weapon.-all of the parts that make up the

ammunition necessary to fire one shot. Around consists of a primer, a propellingcharge, a projectile, and a fuze. In fixedammunition, these parts of a round are heldtogether with a shell case. In small armsammunition, the projectile is called abullet, and the complete round is called acartridge.

ROUNDS COMPLETE-the term used to report that the number of

rounds specified in fire for effect have beenfired.

sheaf-planned planes of fire that produce a

desired pattern of bursts with rounds firedby two or more weapons.

SHELL (specify)-a command or request indicating the type

of projectile to be used.

shell-a hollow projectile filled with explosive,

chemical, or other material as opposed toshot, which is a solid projectile.

-a shotgun cartridge.--to bombard; to fire a number of rounds at a

target.

shift-the transfer of fire from one target to

another.--to transfer fire from one target to another.

Glossary-i 0



FM 6-40

-the deflection difference from onedesignated point to another used inopening or closing the sheaf of artillery ormortar units.

SHORT

-a spotting or an observation reportedby a

spotter or an observer to indicate that aburst occurred short of the target in relationto the spotting line.

short-a round that strikes or bursts on the near

side of the target; a round fired withoutsufficient range to reach the target.

shot-pellets, small balls, or slugs used in

shotgun shells, canisters, and some other

types ofammunition.

-a report that indicates that a gun or gunshave been fired.

side spray-fragments from a bursting shell that are

thrown sideways from the line of flight.

special sheaf-a type of sheaf in which each gun fires a

unique time, deflection, and'quadrantelevation to cause the rounds to impact in aspecific geometrical pattern.

SPLASH-a word transmitted by a firing ship or

artillery fire direction center to the spotter 5seconds before the estimated time of theimpact of a salvo or a round.

spotting-a process of determining, by visual or

electronic observation, deviations ofartillery or naval gunfire from the target inrelation to a spotting line.

-the process of supplying necessaryinformation for the adjustment or theanalysis of fire.

spotting line-the gun-target line, the observer-target

line, or a reference line used by the spotteror observer in making spot corrections.

square--n artillery, a mark or measurement onprojectiles to denote standard weight ordeviation from a standard weight.

supplemental charge-a cylindrical container, usually filled with

trinitrotoluene, used in deep-cavitizedprojectiles to fill the void between anordinary fuze and booster combination andthe bursting charge.

sustained rate of fire-the actual rate of fire that a weapon can

continue to deliver for an indefinite lengthof time without seriously overheating.

T

target grid-a device for converting the observer's

target locations and corrections withrespect to the observer-target line to targetlocations and corrections with respect to

the gun-target line.time of flight-the time, in seconds, from the instant a

projectile leaves the muzzle of a weapon tothe instant it strikes or bursts.

trajectory-the path of a projectile, missile, or bomb in

flight,

transfer limit-the maximum difference in direction and

range from the location of a checkpoint

withinwhich limits corrections computed

for the checkpoint are assumed to besuff ic ien t ly accura te to war ran tapplication to any target justifying itsattack by a transfer of fire.

U

UP-a term transmitted in a call for fire to

indicate that the target is higher in alti-tude than the point that has been used asa reference point for the target location.

-a correction used by a spotter or an observerto indicate that an increase in height ofburst is desired.

V

vertical angle-the angle measured vertically, up or down,

from a horizontal plane of reference. Thevertical angle is expressed as plus or minusdepending on whether the position is above

Glossary- 11



FM 6-40

(plus) or below (minus) the horizontalplane.

vertical clearancethe vertical distance by which a projectilemust clear an intervening crest.

vertical intervalthe difference in altitude between twospecified points or locations; for example,

the battery or firing ship and the target, theobservation post and the target, thelocation of a previously fired target and anew target, the observer and a height ofburst, and a battery or~firing ship and aheight of burst.

-the difference in height between theweapon and the desired burst point.

ACRONYMS AND ABBREVIATIONS

ACADAM

adjAFaltAM CAOAPICM

appATGM

az

balBCS

BCUBMA

bnbtryBUCS

calCBCEOI

CFCFFchgcomp sitecorr

Glossary-i 2

aiming circle

area denial artillerymunitionsadjust, adjusting, adjustedadjust firealtitudeat my commandair observerantipersonnel improvedconventional munitionsapparentantitank guided missile

azimuth

ballisticsbattery computer system

battery computer unitbattery-minefield angle

battalionbatterybackup computer system

calibercenter of batterycommunications-electronicsoperation instructionscommand firecall for firechargecomplementary angle of sitecorrection

CSF

CSRctg

dEdfdHDMDdNDNLDPICM

DSDTG

EFCelEOLEOMEXEC

complementary angle of site

factorcontrolled supply ratecartridge

difference in eastingdeflectiondifference in heightdigital message devicedifference in northingdo not loaddual-purpose improvedconventional munitionsdirect supportdate-time group

equivalent full chargeelevationend of the orienting lineend Of missionexecute (TACFIRE and BCS)

FA field artilleryFADAC field artillery digital

automatic computerFASCAM family of scatterable minesFCI fire control informationFCO fire control officerFDC fire direction centerFDO fire direction officerFFE fire for effect



FM 6-40

FISTFLOTFOFPFFSFSEFSOFTFTXfz

GBGBCGDUGil?GMET

GQGSRGSTGTAZGTRGG/VLLD

fire support teamforward line of own troops

forward observerfinal protective fires

fuze settingfire support element

fire support officer

firing table

field training exercisefuze

green bag

geographical battery center

gun display unit

graphical firing tablegraphical munitionseffectiveness table

gunner's quadrant

general support reinforcing

graphical site tablegun-target azimuth

gum-target range

ground/vehicular laserlocator designator

high anglehigh burst,height of burst

hydrochloroethanehorizontal control operator

high explosive

high explosive plastic

high explosive spotting

high explosive tracer

hand-held calculatorheight of burst

in accordance withInternational Civil AviationOrganizationimproved conventionalmunitionilluminationinfrared

JMEM

JMEM/SS

LA

m

m/MAP MODmaxMDPmetMHL

MIJI

minMPIm/sMSUMTMTOMTSQMVMVV

NBC

NCS

OLOBOPOPCODEosOT

OT1VI

PADS

PD

Glossary-I 3

joint munitions effectivenessmanualjoint munitions effectivenessmanual for surface-to-surface weapons

low angle

metermilmap modificationmaximummeteorological datum plane

meteorological, meteorology

manufacturer's hairline

meaconing,intrusion,

jamming, interferenceminutemean point of impactmeters per second

mutual support unitmechanical time

message to observer

mechanical time super quick

muzzle velocity

muzzle velocity variation

nuclear, biological,chemicalnet control station

orienting lineoperator-burstobservation post

operations codeorienting stationobserver-targetobserver-target vertical

interval

position and azimuthdetermining systempoint detonating

HAHB

HCHCOHEHEPHESHETHHCHOB

IAWICAO

ICM

illumir



FM 6-40

PEDPEHB

PE RPERB

% CAS

PETBPEVPMCS

pltPMODPRFproj

proxPTF

QQEQSTAG

RAAMS

RAPRATELOrdRDP

deflection probable errorheight-of-burst probableerrorrange probable errorrange-to-burst probable

errorpercentage of casualties(on GMET)time-to-burst probable errorvertical probable errorpreventive maintenancechecks and servicesplatoonpowder modelpulse repetition frequencyprojectileproximitypiece to fire

quickquadrant elevationquadripartite standardizationagreement

remote antiarmor minesystem

rocket-assisted projectileradiotelephone operatorroundrange-deflection protractor

registration pointreplotrangeremotely piloted vehicleradii of target, radius of target

WPwpnWR

yd

SCASDsecsismkSTANAGSTX

TACFIRETAGTBGTFTFCTFTtgttiTLETOE

TOTtot

UTM

VA

VCOVFMED

VIVT

white phosphorusweaponwhen ready

yard

Glossary-i 4

section chief assemblyself-destructsecondssitesmokestandardization agreementsituational training exercise

tactical fire direction systemtarget above guntarget below guntime of flighttotal fuze correctiontabular firing tabletargettimetarget location errortables of organization andequipmenttime on targettotal

universal transverse mercator

vertical angle

vertical control operatorvariable format messageentry devicevertical intervalvariable time

reg ptreprgRPVRT



FM 6-40

REFERENCES

PUBLICATION INDEXESDepartment of the Army pamphlets of the 310-series should be consulted frequently for the

latest changes or revisions to references in this appendix and for new publications relating to

material covered in this publication.

ARMY REGULATIONS (AR)

310-25 Dictionary of United States Army Terms

310-50 Catalog of Abbreviations and Brevity Codes

385-63Policies and Procedures for Firing Ammunition for

Training, Target Practice, and Combat

DEPARTMENT OF THE ARMY PAMPHLETS (DA PAM)

310-1 Consolidated Index of Army Publications and Blank Forms

DEPARTMENT OF ARMY FIELD MANUALS (FM)

3-106-16-26-13E1/2/3

6-156-20 (HTF)6-20-1 (HTF)6-20-2 (HTF)

6-306-40-3

6-506-1216-1226-141-1

6-141-2

6-1616-30021-221-6

Employment of Chemical AgentsField Artillery Fire Direction System TACFIRE OperationsField Artillery Survey

Soldier's Manual: 13E, Cannon Fire Direction Specialist(Skill Levels 1/2/3)Field Artillery MeteorologyFire Support in Combined Arms OperationsField Artillery Cannon BattalionDivision Artillery, Field Artillery Brigade, and Field

Artillery Section (Corps)The Field Artillery Observer

Operation of the Gun Direction Computer M18, CannonGunnery ApplicationField Artillery Cannon BatteryField Artillery Target AcquisitionField Artillery Sound Ranging

Field Artillery Target Analysis and Weapons Employment:Nonnuclear(C) Field Artillery Target Analysis and WeaponsEmployment: Nonnuclear (U)Field Artillery Radar SystemsArmy Ephemeris, 1983-1987Soldier's Manual of Common Tasks, Skill Level 1How to Prepare and Conduct Military Training

References-I



FM 6-40

21-2623-9023-9123-9224-1 (HTF)24-1825-2 (Test)100-5 (HTF)101-5-1 (HTF)101-31-1

101-60-17

Map Reading81-mm MortarMortar Gunnery4.2-Inch Mortar, M30Combat CommunicationsField Radio

TechniquesHow to Manage Training in UnitsOperationsOperational Terms and GraphicsStaff Officers' Field Manual: Nuclear Weapons EmploymentDoctrine and Procedures(C) Basic Effectiveness Manual, Surface-to-Surface

TECHNICAL MANUALS (TM)

5-241-2

5-2805-203-14

5-6115-271-14

6-2309-1220-221-10/1

9-1229-242-12&P

9-1260-477-12

9-1300-2009-6920-361-13&P

11-5820-401-1

11-5820-401-10-2

Universal Transverse Mercator Grid: Zone-to-ZoneTransformation TablesOperator, Organizational, Intermediate (Field) (DirectSupport and General Support) and Depot Level MaintenanceManual: Engine, gasoline, 6 HPOperator's, Organizational, Direct Support and GeneralSupport Maintenance Manual for Generator Set, GasolineEngine Driven, Skid mtd, Tubular Frame 3 KW, 3 Phase,AC, 120/208 and 120/240 V, 28 V DC (Less Engine)(DOD Model MEP-016A), 60 HZ, (Model MEP-021A) 400 HZ and(Model MEP-021A), 400 HZ and (Model MEP-026A) 28 V DCLogarithmic and Mathematical TablesOperator's Manual for Computer, Gun Direction, M18(Counterfire FADAC)Operator's and Organizational Maintenance Manual,Including Repair Parts and Special Tool List forComputer Set, Field Artillery, General and ComputerSet, Field Artillery, MissileOperator's and Organizational Maintenance Manual forElectro-Optical Target Designator Set, AN/TVQ-2 (G/VLLD)and G/VLLD Ml13A1 Vehicle AdapterAmmunition, GeneralOperator, Organizational and Direct Support MaintenanceManual (Including Repair Parts and Special Tools List):Field Artillery Trainer Kits (With Field Artillery Trainer M31)Operator's Manual: Radio Sets, AN/VRC-12, AN/VRC-43,AN/VRC-44, AN/VRC-45, AN/VRC-46, AN/VRC-47,AN/VRC-48 and AN/VRC-49 (Used Without an IntercomSystem)Operator's Manual: Radio Sets, AN/VRC-12, AN/VRC-43,AN/VRC-44, AN/VRC-45, AN/VRC-46, AN/VRC-47,AN/VRC-48 and AN/VRC-49 (Used With an IntercomSystem)

References-2



FM 6-40

11-5820-477-12

11-5830-340-12

11-5860-201-1011-5985-357-13

11-7440-283-12-1

38-75043-0001-28

Operator's and Organizational Maintenance Manual: Radio

Set Control Groups AN/GRA-39, AN/GRA-39A and AN/GRA-39BOperator's and Organizational Maintenance Manual(Including Repair Parts and Special Tools Lists):

Intercommunication Set, AN/VIC-1(V) Controls,

Intercommunications Set, C-10456/VRC, C-10680/VRC andAmplifier, Audio Frequency, AM-7046/VRC

Operator's Manual: Laser Infrared Observation Set AN/GVS-5

Operator's, Organizational, and Direct Support MaintenanceManual for Antenna Group, OE-254/GRCOperator's and Organizational Maintenance Manual for

Computer Group, Gun Direction, OL-200/GYK-29(V)The Army Maintenance Management System (TAMMS)Army Ammunition Data Sheets for Artillery Ammunition:

Guns, Howitzers, Mortars, Recoilless Rifles, GrenadeLaunchers, and Artillery Fuzes (Federal Supply Class1310, 1315, 1320, 1390)

TRAINING CIRCULARS (TC)

6-1-2 Battery Computer System

6-20-3 Fire Support Operations in Brigade-Size Units

DA FORMS (AVAILABLE THROUGH NORMAL AG PUBLICATIONSSUPPLY CHANNELS)

2028 Recommended Changes to Publications and Blank Forms

2408-4 Weapon Record Data

3675 Ballistic Met Message3677 Computer Met Message

4176 Target Plotting Grid Field Artillery Graduated in Mils andMeters Scale 1:25,000

4200 Met Data Correction Sheet

4201 High Burst (Mean Point of Impact) Registration

5336-R 203-mm Nuclear Computation for M753 Rocket-AssistedProjectile

5337-R 203-mm Nuclear Computation Work Sheet for M422A1

4504 Record of Fire

4505 155-mm Nuclear Computation-Met Correction Technique

4757 Registration/Special Correction Work Sheet4758 Section Chief's Card, Computation Work Sheet

5338-R Computer's Checklist

4982-R Muzzle Velocity Record

4982-1-R M90 Velocimeter Work Sheet'

5032-R Field Artillery Delivered Minefield Planning Sheet

FIRING TABLES (FT)

8-Q-1 Cannon, 8-Inch Howitzer, M201 on Howitzer, Heavy, Self-

Propelled: 8-Inch, Ml0Al and Cannon, 8-Inch Howitzer,

References-3



FM 6-40

8-S-1

155-ADD-I-1

155-ADD-J-1155-ADD-L-i

155-AJ-2

155-AN-1

M201A1 on Howitzer, Heavy, Self-Propelled: 8-Inch M11OA2and Firing Projectile, HE, M106Cannon, 8-Inch Howitzer: M201A1 on Howitzer, Heavy,Self-Propelled, 8-Inch: M11OA; Firing Projectile, HE,RA: M650 and Projectile, Atomic: XM753Addendum to FT 155-AM-1 for Projectile, HE, M449A1(M449E2); M449 (T379) and M449E1Addendum to FT 155-AN-1 for Projectile, HE, M483A1Firing Table Addendum to FT 155-AN-1 for Projectile,HE, M692 and Projectile, HE, M731Cannon: 155-mm Howitzer, M126A1 and M126 on Howitzer,Medium, Self-Propelled: 155-mm, M109; Cannon: 155-mmHowitzer, M185 on Howitzer, Medium, Self-Propelled: 155-mm,M109A1; Cannon: 155-mm Howitzer, MiA2 on Howitzer, Medium,Towed: 155-mm, M114A2; Cannon: 155-mm Howitzer, DM 2on Howitzer, Medium, Self-Propelled: 155-mm, M109G;Cannon: 155-mm Howitzer, M199 on Howitzer, Medium, Towed:155-mm, M198 and Firing Projectile, Atomic: M454Cannon, 155-mm Howitzer, M185 on Howitzer, Medium,Self-Propelled, 155-mm, M109A1 and Howitzer, Medium,Self-Propelled, 155-mm, M109A1B Firing Projectile, HE,M483A1

MISCELLANEOUS PUBLCATIONS

ARTEP 6-100STANAG 4119QSTAG 22 0

QSTAG 224

QSTAG 225QSTAG 246MVCT-M90-1

References-4

The Field Artillery Cannon BatteryAdoption of a Standard (Cannon) Artillery Firing Table FormatCannon Artillery Equipment and Procedures for the ManualDetermination of Firing Data for Nonstandard Conditionsfor Post 1970Manual Fire Direction Equipment, Target Classificationand Methods of Engagement for Post 1970Call for Fire FormatsRadio-Telephone Procedures for the Conduct of Artillery FireMuzzle Velocity Correction Tables, M90 Velocimeter

Note. Because of the rapidly changing status of firing tables, the Gunnery Department, USAFAS,publishes annually a list of current firing table information. The publication is Gunnery R& ADivision Reference Note 1. Users may request a copy and be placed on the mailing list by writing:

CommandantUS Army Field Artillery SchoolATTN: A TSF-GAFort Sill, OK 73503

.. . .. .............



FM 6-40

USAFAS TRAINING SUPPORT PUBLICATIONS

References-5

Note. A copy of MVCT-M90-1 may be obtained by writing:

CommandantUS Army Field Artillery SchoolA TTN: ATSF-GA

Fort Sill, OK 73503

Note. A copy of the Field Artillery Catalog of Instructional Material may be obtained by writing:

CommandantUS Field Artillery School

ATTN: A TSF- CR- TSFort Sill, OK 73503



FM 6-40

INDEX

ADAM; 9-12, 9-13, 9-14, 9-15,9-18

Adjust fire; 9-3

Adjusted deflection; 7-3, 10-16,12-20

Adjusted elevation; 7-3, 10-16,12-20

Adjusted time; 7-3, 10-16, 12-20

Air observer; 13-25

Angle of site; 3-5, 7-13

Angle T; 5-12, 6-14, 9-44

APICM; 9-4

Ascending branch; 3-5

Assurance table; 12-2

Azimuth index; 5-7

Ballistic met; 10-6

Ballistic mode; 9-35, 9-46

BCS FDC; 1-2, 4-1

Bourrelet; 3-1

Calibrated muzzle velocity; 11-1,

11-2

Calibration; 11-1

Cannon tube; 3-1

Charge selection; 9-43

Chart; 5-3

Chart operator; 4-1, 4-2, 12-19,13-33

Chief computer; 4-1 through 4-4

Circular targets; 13-15

Cloud height; 9-44

Complementary range; 3-5, 10-11

Copperhead; 9-35 through 9-40,9-42, 9-43, 9-47, 9-48

Coppering; 3-2

Correction to air temperature anddensity; 10-11Correction to muzzle velocity;10-11

Deflection correction; 10-21

Deflection index; 5-8

Degradation; 4-1, 4-2

Descending branch; 3-5

Designate; 9-35, 9-65

Dispersion rectangle; 3-7

DPICM; 13-39

Elevation; 3-5

Elevation gage line; 7-2

Emergency firing chart; 14-1, 14-2

Estimation/pacing; 13-3

Executive officer's high burst; 14-7

FADAC FDC; 4-2

FASCAM; 9-8

Final protective fires; chap 13, sec IV

Fire command elements; 6-8

Fire commands; chap 6, sec III

Fire command reports; 6-11

Fire direction center; 1-2

Fire direction equipment; 5-4

Fire direction officer; 4-1 through4-3

Fire order; chap 6, sec 1, 6-5, 9-42

Fire in effect; 6-5, 13-8, 13-13,13-14

Firing data checks; 4-1, 4-2, 4-6

Firing unit muzzle velocity variation;11-1

Footprint; 9-35

Glide mode; 9-35

Graphical firing table; chap 7, sec I,9-47, 9-52, 9-67, 13-36

Graphical firing table fan; chap 7, secII, 7-3, 7-5, 7-7Graphical firing table setting; 7-3,7-6, 9-48, 9-50, 9-56, 9-68,12-11

Graphical site table; chap 7, sec IV

Grid coordinates; 5-5, 5-10, 12-18

Hasty traverse; 13-2

HB/MPI registration; 12-13

High angle; 9-66, 9-67, 9-70, chap13, sec Iii, 13-37, 13-38

High explosive; 9-2

Horizontal control operator; 4-1,4-3

Illumination projectile; 9-6, 9-7

Inferred calibration; 11-1

Massing fires; 6-5, 13-21

Maximum ordinate; 3-5

Measured muzzle velocity; 11-1,11-3

Message to observer; chap 6, sec III,9-40

Met

ballistic; 10-6, 10-16

concurrent 10-1, 10-2, 10-10,10-11, 10-12, chap 10, sec III

computer; 10-7

corrections; 10-2, 10- 11

errors; 10-8

message; 10-5

subsequent- 10-1, 10-3, 10-14through 10-17, chap 10, sec IV

validity; 10-9

met + VE; 10-4, chap 10, sec VI,12-12

Muzzle velocity measurement; 11-2

Muzzle velocity variations; 3-2,11-1

MVCT-90-1 ; 11-2

Index-1



FM 6-40

Nonstandard conditions; 10-1

Nuclear gunnery

155-mm howitzer delivery; 9-31,9-32

K-transfer; 9-33, 9-34

203-mm howitzer delivery; 9-24,9-25, 9-29

computer, 9-30K-transfer; 9-25, 9-26met + VE; 9-25, 9-27observer adjustment, 9-25, 9-28

Observed fire chart; 14-2 through

14-10

Observer; 1-1, chap 13, sec VObturator band; 3-1

Offset correction; 9-45On-call target; 9-35

Origin; 3-5

Piece displacement; 12-7, 13-1

Planned targets; 9-35Plotting board, M10/M17; 13-6,13-7, chap 14, sec iiPolar plot; 5-10, 13-33Position constants; 10-2, 10-13,10-15, 10-16

Position corrections; 13-8, 13-14

Powder model; 11-1

Preferred charge; 11-1

Priority targets; 9-35Probable error; 3-7

deflection; 3-9height of burst; 3-11

range; 3-8Projectile; 3-1, 3-2Projectile family; 1 1-1

Copperhead; chap 9, sec V

OP/CM; hap 9, sec ii

high explosive; chap 9, sec I

nuclear; chap 9, sec IV

rocket assisted projectile; chap 9,sec V

Propellant; 3-1, 3-2

Propellant lot; 11-1

Propellant residue; 3-2Propellant type; 11-1

Pulse repetition frequency; 6-14,9-41

RAAMS; 9-8, 9-12 through 9-14

Range-deflection protractor; 5-4Range gage line (MHL); 7-2

Ranging rounds; 13-27

Readout average; 11-1

Record of fire (DA Form 4504); chap9 introduction, 9-63

Registrationsabbreviated G/VLLD; 12-1, 12-10

abbreviated HB/MPI; 12-1

abbreviated precision; 12-1

adjust fire mission; 12-1

DPICM; 13-39

HB/MPI; 12-1, 12-13, 12-17

multilot 12-9

offset; 12-1

precision; 12-1, 12-4, 12-5, 12-6,12-8

radar; 12-1

to the rear; 12-1

Registration/special correctionwork sheet (DA Form 4757); 12-7,13-12

Replot; chap 8, sec IRotating band; 3-1, 3-2

Rotation corrections; 10-11

Round-to-round variations; 3-6

Sheaf

converged;- 13-8, 13-14parallel; 13-8, 13-14

special; 13-8, 13-15

Shift from a known point; 5-10

Site; 3-5, 7-10, 7-12, 7-16, 7-17,9-58, 13-37

Smoke projectile (M825 and HC);9-5, 9-20

Splash; 6-14

Survey; 13-4

Surveyed firing chart; 5-1, 5-2,14-14 through 14-17

Sweep and zone fire; 13-22

Switch setting; 9-57

Tabular firing table; chap 7, sec Ill,

12-12, 10-16

Target grid; 5-4

Three-grid target; 13-15

Tick mark; 5-6

Time gage line; 7-.3, 7-4

Time setting;7-2,

7-4,7-5, 9-53

Time fuze correction; 10-12, 10-16,10-21

Total range correction; 10-12,10-16, 10-21

Trajectory; 3-5, 9-46

Trajectory elements; 3-5

Transfer limits; 9-49, 9-55, 10-17,13-38

Tube conditioning; 3-2

Tube wear; 3-2

Two-grid target; 13-15

Trained observer; 13-30

Unit corrections; 10-11

Velocity error; 10-4, 10-20, 10-21

Velocity trends; 3-2

Vertical angle; 7-12, 7-13, 12-15

Vertical control operator; 4-1, 4-3Vertical interval; 3-5, 7-14

Wind components; 10-11

Zone-to-zone transformation; chap

13, sec VI

Index-2



FM 6-40

7 DECEMBER 1984

By Order of the Secretary of the Army:

JOHN A. WICKHAM, JR.General, United States Army

Chief of Staff

Official:

DONALD J. DELANDROBrigadier General, United States Army

The Adjutant General

DISTRIBUTION:

Active Army, ARNG, and USAR: To be distributed in accordance with DA Form 12-11A, Require-ments for Field Artillery Cannon Gunnery (Qty rqr block no. 44); Operation of the Gun Direction

Computer M18, Cannon Gunnery Application (Qty rqr block no. 48) and Field Artillery CannonBattalions and Batteries (Qty rqr block no. 72).

Additional copies may be requisitioned from the US ArmyAdjutant General Publications Center,2800 Eastern Boulevard, Baltimore, MD 21220.



DEPARTMENT OF THE ARMY

U. S. ARMY AG PUBLICATIONS CE2800 EASTERN BOULEVARD

BALTIMORE,MARYLAND21220-2896

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Documents

FM 640 1984 OBSOLETE Field Artillery Cannon Gunnery