of 406/406
MCWP 3-15.1 Machine Guns and Machine Gun Gunnery U.S. Marine Corps PCN 143 000014 00

Machine Guns and Machine Gun Gunnery - marines.mil 3-15.1.pdf · Machine Guns and Machine Gun Gunnery _____ vii Machine Guns and Machine Gun Gunnery

  • View
    82

  • Download
    13

Embed Size (px)

Text of Machine Guns and Machine Gun Gunnery - marines.mil 3-15.1.pdf · Machine Guns and Machine Gun...

  • MCWP 3-15.1

    Machine Guns and Machine Gun Gunnery

    U.S. Marine Corps

    PCN 143 000014 00

  • DEPARTMENT OF THE NAVYHeadquarters United States Marine Corps

    Washington, D.C. 20380-0001

    1 September 1996

    Foreword

    1. PURPOSE

    Marine Corps Warfighting Publication (MCWP) 3-15.1, Machine Guns and Machine Gun Gun-nery, describes how various machine guns are maintained and employed by the U.S. MarineCorps' machine gun crews. It also provides the principles and techniques for their use in engag-ing and destroying enemy targets.

    2. SCOPE

    This reference publication is designed for machine gunners, platoon commanders, platoon ser-geants, S-3 officers and chiefs, armorers, and ammunition technicians. It outlines a standardizedway to train Marine machine gunners through the use of gunnery tables.

    3. SUPERSESSION

    FMFRP 6-15, Machineguns and Machinegun Gunnery, dated 17 August 1988.

    4. CHANGES

    Recommendations for improving this manual are invited from commands as well as directly fromindividuals. Forward suggestions, using the User Suggestion Form format, to

    Commanding GeneralDoctrine Division (C 42)Marine Corps Combat Development Command3300 Russell Road Suite 318AQuantico, Virginia 22134-5021

    5. CERTIFICATION

    Reviewed and approved this date.

    BY DIRECTION OF THE COMMANDANT OF THE MARINE CORPS

    PAUL K. VAN RIPERLieutenant General, U.S. Marine Corps

    Commanding GeneralMarine Corps Combat Development Command

    Quantico, Virginia

    DISTRIBUTION: 143 000014 00

  • Machine Guns and Machine Gun Gunnery _____________________________________________________________________ iii

  • Machine Guns and Machine Gun Gunnery ______________________________________________________________________ v

  • Machine Guns and Machine Gun Gunnery _____________________________________________________________________ vii

    Machine Guns and Machine Gun Gunnery

    Table of Contents

    Page

    Chapter 1. Introduction to Machine Guns

    Chapter 2. Machine Gun, Light, Squad Automatic Weapon, M249Section 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1Section 2. Disassembly and Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7Section 3. Functioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20Section 4. Malfunctions and Stoppages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24Section 5. Mounts and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27Section 6. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29Section 7. Ammunition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-37Section 8. Operation and Firing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-40Section 9. Qualification Firing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-45

    Chapter 3. Machine Gun, 7.62mm, M240GSection 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1Section 2. Disassembly, Assembly, and Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7Section 3. Functioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19Section 4. Malfunctions and Stoppages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23Section 5. Mounts and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27Section 6. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-38Section 7. Ammunition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-41Section 8. Operation and Firing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-45Section 9. Gun Drill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-50Section 10. Qualification Firing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-56Section 11. Firing with Blank Ammunition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-62

    Chapter 4. Machine Gun, Caliber .50, Browning, M2HBSection 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1Section 2. Disassembly, Assembly, and Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7Section 3. Headspace and Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-26Section 4. Functioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-29Section 5. Malfunctions and Stoppages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-35Section 6. Mounts and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-39Section 7. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-43Section 8. Ammunition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-47Section 9. Operation and Firing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-53Section 10. Gun Drill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-56Section 11. Qualification Firing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-64

  • viii ____________________________________________________________________________________________________ MCWP 3-15.1

    Chapter 5. Machine Gun, 40mm, MK-19 MOD 3Section 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1Section 2. Disassembly, Assembly, and Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7Section 3. Functioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15Section 4. Malfunctions and Stoppages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20Section 5. Mounts and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22Section 6. Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30Section 7. Ammunition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-32Section 8. Operation and Firing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-36Section 9. Gun Drill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-40

    Chapter 6. Employment and GunnerySection 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1Section 2. Characteristics of Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9Section 3. Classes of Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12Section 4. Range Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16Section 5. Traversing and Elevating Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18Section 6. Fire Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-21Section 7. Methods of Target Engagement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-25Section 8. Overhead Fires. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-36Section 9. Techniques of Predetermined Fire. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-42Section 10. Final Protective Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-46Section 11. Range Cards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-49Section 12. Firing From Defilade Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-53Section 13. Machine Gunners Mathematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60Section 14. Antiaircraft Gunnery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-64Section 15. Firing Positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-72Section 16. Wire Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-75

    AppendicesAppendix A. M60E3/M240G Firing Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1Appendix B. M2 .50 Cal Firing Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1Appendix C. MK-19 MOD 3 Firing Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1Appendix D. Destruction of Machine Guns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1Appendix E. Infantry Plotting Board M17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1Appendix F. Adjustment of Indirect Machine Gun Fire. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F-1Appendix G. Final Protective Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G-1Appendix H. Acronyms and Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H-1Appendix I. References and Related Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-1

    Notes

  • Chapter 1

    INTRODUCTION TO MACHINE GUNS

    For their part the machine-gun units must be on the alert to seize and exploit every opportu-nity to assist the forward movement of the rifle units, without waiting for specific orders to en-gage a particular targe or locality.

    FMFRP 12-2, Infantry In Battle1

    Leaders must know what the guns can do before the attack starts, what they can do while theattack is in progress, and what they can do during reorganization and consolidation. Theymust learn to seek and to recognize opportunities for employing machine guns in every phaseof the action. Finally, they must have the aggressiveness to keep everlastingly at the task ofgetting the guns forward, so that when opportunity does present, they will be able to seize it.

    FMFRP 12-2, Infantry In Battle2

    Desert Storm, KuwaitA Marine Machine Gunner Scans the Desert For Targets

  • 1-2 ____________________________________________________________________________________________________ MCWP 3-15.1

    Table of Contents

    1001 History1002 Types of Machine Guns1003 Machine Gun Employment

    1004 Principles of Machine Gun Employment

    List of Figures

    1-1 Marine Automatic Rifleman, Operation Desert Shield

    1-2 Marines From the Enlisted InstructorCompany Train New Lieutenants in the Field, The Basic School, Quantico, Virginia

    1-3 Heavy Machine Gun Squad in TrainingDuring Operation Desert Shield

  • Chapter 1

    Introduction to Machine Guns

    1001. HistoryDespite their post-Civil War development, modernmachine guns didnt begin to exhibit their full potentialin battle until World War I. The effects on employ-ment of these new weapons systems altered the doctri-nal way of waging war for both Allied and Axispowers. Properly employed machine guns proved to bedevastating to massed infantry formations and pavedthe way for the creation of a whole new methodologyof warfighting. The machine gun became the keystoneof the infantry defense and a major supplier of organicfirepower in the offense. New tactics were being devel-oped by both sides to not only exploit the effects of themachine gun, but to counter the enemys machine gunemployment capabilities.

    The machine gun changed the face of modern warfarejust as surely as the development of aircraft and preci-sion indirect fire artillery. The impact of this weaponcan be seen not only in military writings of thatperiod, but in the principles of employment still in usetoday. FMFRP 12-2, Infantry in Battle, a compilationof lessons learned from World War I, provides awealth of knowledge concerning the employment ofmachine guns. These lessons remain applicable andare still studied today, almost 70 years later. Theproper employment of machine guns has won many abattle at the company and platoon level, and a wellrehearsed, proficient machine gun team can some-times make the difference between success and fail-ure on the battlefield. Military history is filled withexamples of the impact that machine guns and theirgunners have had in turning the tide of battle:

    Machine guns affect the outcome of battle byfire power alone. Guns that have not fired have notattacked, no matter how many times they have beenplaced in position.3

    The machine gun acts by fire alone; move-ment of this weapon has no other purpose than tosecure positions from which more effective fire can bedelivered. Maximum usefulness is obtained only whenevery gun within range of the enemy is firing effec-tively against him.4

    Although machine guns lend themselvesmore readily to the defense than to the attack, this isno excuse for a failure to exact the utmost from themin support of advancing troops. The handicaps totheir effective employment in the attack can be andmust be overcome.5

    Though the weapons themselves have changed overthe years and will continue to do so, the basic consid-erations for their employment remain constant. Theexcerpts from FMFRP 12-2, listed above, serve asreminders of this fact, and the lessons contained inthem are just as applicable today as when they werefirst written.

    1002. Types of Machine GunsMachine guns are classified as light, medium, orheavy. Classifications are determined by a combina-tion of weapon caliber, weapon system weight, crewsize, and the primary type of intended target.

    a. Light Machine Guns/Automatic Rifles. Thelight machine gun (LMG) classification generallyincludes .22 to .250 caliber (5.45mm to 6mm) auto-matic weapons. An LMG typically weighs between 15and 30 pounds, complete. An LMG is normallymanned by a crew of one or two individuals depend-ing on the accessories being used. Neither a tripod nora spare barrel is normally used with an LMG when itis manned by a single individual. Bullet weights forLMGs normally range from 45 to 72 grains. They areoptimally employed against exposed and lightly pro-tected personnel at ranges less than 1,000 meters. In

  • 1-4 ____________________________________________________________________________________________________ MCWP 3-15.1

    this category, the Marine Corps employs the squadautomatic weapon, M249, 5.56mm. Figure 1-1 pro-vides an example of a Marine using an LMG.

    b. Medium Machine Guns. This medium machinegun (MMG) classification generally includes .264 to.33 caliber (6.5mm to 8mm) automatic weapons. Typ-ical MMG weights are 25 pounds or more whenloaded with 50 rounds of ammunition. Remainingammunition, ground tripod, spare barrel, and otheraccessories can add another 25 pounds or more to theoverall weight of MMG systems. The MMG is gener-ally employed by a crew of three. A MMG generallyuses bullets that weigh between 140 and 220 grains.Optimally, they are employed against personnel andlight materials ( e.g., motor vehicles) at ranges of1500 meters or less. In this category, the MarineCorps employs several variants of the 7.62mm,M240G machine gun. Figure 1-2 show Marines train-ing with a MMG.

    c. Heavy Machine Guns. The heavy machine gun(HMG) classification generally includes .50 caliberor larger (12.7mm to 15mm) automatic weapons. Thesystem weight of a heavy machine gun is substantial.In a ready to fire configuration using a ground tripod,an HMG without ammunition can weigh more than125 pounds. An HMG is normally manned by a crewof four or more personnel (although a crew of threemay be sufficient if motor vehicles or draft animalsare employed for transportation over distance). Thecommon bullet weight of an HMG is 700 grains orlarger. HMGs are primarily employed against fieldfortifications, vehicles, and aircraft. They are gener-ally effective against these types of targets at rangesof 1,000 meters or greater. The machine guns fromthis category currently employed by the Marine Corpsare the caliber .50, Browning, M2HB, machine gunand the 40mm, MK-19 MOD 3 machine gun. Figure1-3 portrays a HMG squadron during OperationDesert Shield.

    Figure 1-1. Marine Automatic Rifleman, Operation Desert Shield.

  • Machine Guns and Machine Gun Gunnery ____________________________________________________________________ 1-5

    1003. Machine Gun Employment

    Properly employed, the machine gun provides a highvolume of accurate fire in support of the infantry inboth the offense and defense. In the offense, themachine gun can add firepower to the assault, but it isoften best employed to suppress or neutralize theobjective from a base of fire. The long-range, closedefensive, and final protective fires of the machinegun provide an integral part of the defense againstinfantry attack. HMGs may also be used to destroylightly armored vehicles or as defense against slow-moving, low-flying aircraft. In addition, the machinegun is used effectively in convoy security, pointdefense of rear area facilities, and other rear-areasecurity missions.

    1004. Principles of Machine Gun Employment

    Maximum efficiency in the tactical employment of alltypes of machine guns can be reached by applying thefollowing principles during planning. Most tactical sit-uations would benefit from the employment of all eightprinciples simultaneously. However, in actuality, theseprinciples are prioritized according to the tactical situa-tion and some may be abandoned in favor of others thatare more crucial. These principles are not meant toserve as absolutes. They are, however, sound ideas,proven in combat, that should be understood and con-sidered by all personnel involved in the operation andemployment of machine guns. Chapter 6 addressesdetailed employment of todays weapons.

    Figure 1-2. Marines From the Enlisted Instructor Company Train New Lieutenantsin the Field, The Basic School, Quantico, Virginia.

  • 1-6 ____________________________________________________________________________________________________ MCWP 3-15.1

    a. Mutual Support. No machine gun should beplaced in isolation. Machine guns should be placedwhere they can cover each other by fire, fires of onemachine gun can help defeat attacks on anothermachine gun. Another reason to place guns so thatthey cover each other is so one gun can fire directly atthe other position if it is overrun. In some instances, itmay be necessary to have other weapons (AT-4 orM203) provide covering fire.

    An important facet of the principle of mutual supportis security. Protection of machine guns should be ofprimary concern. Since machine gun positions inflictdevastating fire upon the enemy, they will come underconcentrated attacks by the enemy in his attempt tostop the attack. To provide protection and security,well-placed riflemen, and/or automatic riflemen areplaced so they can cover approaches that the enemymay use to attack the guns. For example, althoughmachine guns should be placed on the flanks to pro-vide defense, they should not be placed in the last

    position out since this leaves them vulnerable to aflanking attack. A fire team, or perhaps even largerelement, should be positioned outboard of the gunposition. This securely tucks the machine guns intothe defense.

    b. Employed in Pairs. Employing machine gunsin pairs ensures a continuous, high volume of fire. Italso gives the guns the capability of efficiently engag-ing targets of larger width or depth than one machinegun could effectively engage alone. Employment inpairs also provides the opportunity for continued firefrom one machine gun while the other machine gun isreloading or clearing a malfunction or stoppage.

    c. Coordination of Fire. Ensure machine gun fireis coordinated with the fires of other machine gunsand other weapons. In the defensive, the machine gunforms the backbone around which other infantryweapons are organized. The machine gun fire planmust be studied by the leader, other fires are then

    Figure 1-3. Heavy Machine Gun Squad in Training During Operation Desert Shield.

  • Machine Guns and Machine Gun Gunnery ____________________________________________________________________ 1-7

    planned to complement the machine gun fire plan.For example:

    Dead space in a machine guns final protectiveline (FPL) is covered by other indirect and/ordirect fire weapons.

    Indirect fire planned to concentrate along the linewhere the machine guns FPL is expected to stopthe enemy, hitting him when he seeks cover.

    In the offensive, machine gun fire must be coordi-nated with other weapons systems to ensure comple-mentary or additive effects against the enemy duringall phases, i.e.; preparation firing, final assault, con-solidation, and pursuit by fire.

    d. Positioned in Defilade. If at all possible, gunpositions should be in defilade. As previously dis-cussed, the enemy will quickly target gun positions,trying to neutralize or destroy them. Placing themachine guns in defilade provides them with some sub-stantial cover between them and the enemys direct fireweapons. This could be essential to their survival.

    e. Positioned to Produce Enfilade Fire. Toachieve the greatest effect from the machine gun,position it so that the long axis of the beaten zonecoincides with the long axis of the target. This type offire, called enfilade fire, causes the maximum amountof rounds to be concentrated on the maximum amountof targets, significantly increasing the chances of hit-ting targets. Enfilade fire is normally associated withflanking fire.

    f. Interlocking Fire. Ensuring that fire from onemachine gun position interlocks with the fires of othermachine gun positions prevents gaps through whichthe enemy can easily close with and attack friendlypositions. Machine gun fire, properly augmentedwith obstacles and other weapons effects, should

    form a wall of steel between friendly positions andthe enemy.

    g. Cover and Concealment. Well-planned andwell-prepared alternate and supplementary posi-t ions that provide cover and concealment formachine guns are essential. Employ machine gunsfrom a covered and concealed position and do notopen fire until necessary. Once machine guns openfire they may be located by the enemy. Oncemachine gun positions are located, they become ahigh priority target for the enemy. When tacticallyfeasible, employ machine guns from a defilade orpartial defilade position. This provides cover andsome concealment. The use of cover and conceal-ment protects the guns and their crews.

    h. Economy. Machine guns fire at high rates mak-ing excessive ammunition consumption a concern.Wasteful use of ammunition can severely jeopardizethe success of an operation if resupply is slowed orhalted by enemy action, weather, terrain, and/or otherfactors beyond friendly control. Therefore, a detailed,accurate mission analysis plans to use only thosetypes and amounts of ammunition that will effec-tively cripple or destroy the enemy. Rates of fire areused when determining a mission analysis.

    To conserve ammunition, gunners can be taught tocount the length of the burst and to time the pause inbetween bursts. Another way to conserve/regulateammunition expenditure is to employ machine guns inpairs or to use alternating fires. In alternating fires, asone machine gun finishes its burst and is about topause, the other machine gun opens fire This tech-nique is known as talking guns. In addition to con-trolling ammunition consumption, these techniquesalso reduce the wear and tear on a machine gunsoperating parts and prevent overheating and damageto barrels.

  • Chapter 2

    MACHINE GUN, LIGHT, SQUAD AUTOMATIC WEAPON, M249Our main defense was two light machine guns, fairly close together, backup up by two heavy machine guns.We had our riflemen all around them.

    Thats where Joe comes in. His BAR [Browning Automatic Rifle] was to see that no Koreans would sneak upand heave a hand grenade at the machine guns....Those machine guns could lay down a field of fire that couldkeep the mass of the enemy away, but you had to keep a sharp eye out for those that broke through It wouldonly take one or two of them to put those guns out of action....

    [Joe] was killed just before the last attack was repulsed....

    ....about ten yards forward of Joe there was a dead North Korean sergeant. The fellow had a pistol in onehand and a hand grenade in the other. Hed obviously been hit by a BAR. Joe must have gotten him just as hewas going to throw a grenade at our machine gunners.

    Account of Cpl Joseph Vittori, USMC, Company F, 2d Battalion,1st Marines, in Korea, September 1951. Cpl Vittori was

    post-humously awarded the Congressional Medal of Honor.6

    Korea, South Bank of the Soyang Gang RiverA Light Machine Gun Section Moves into Firing Position.

  • 2-2 ____________________________________________________________________________________________________ MCWP 3-15.1

    Table of Contents

    Section 1. Introduction2101. General Data2102. Sights2103. Safety2104. Roles of the SAW

    Section 2. Disassembly and Assembly2201. General Disassembly2202. General Assembly2203. Detailed Disassembly and Assembly

    Section 3. Functioning2301. Feeding2302. Chambering2303. Locking2304. Firing2305. Unlocking2306. Extracting2307. Ejecting2308. Cocking

    Section 4. Malfunctions and Stoppages2401. Malfunctions2402. Stoppages2403. Immediate Action2404. Remedial Action

    Section 5. Mounts and Accessories2501. Bipod2502. Spare Barrel Bag2503. Night Vision Sights

    Section 6. Maintenance

    2601. Care and Cleaning Before, During, and After Firing

    2602. Normal Maintenance Procedures2603. Special Maintenance Procedures2604. Inspection

    Section 7. Ammunition

    2701. Classification2702. Identification2703. Ballistic Data2704. Ammunition Packaging2705. Storage2706. Care, Handling, and Preservation of Ammunition

    Section 8. Operation and Firing

    2801. Loading2802. Unloading2803. Operation of the Safety2804. Firing the SAW2805. Change Barrel Procedures

    Section 9. Qualification Firing

    2901. Fundamentals of Marksmanship2902. Position and Grip2903. Sight Settings and BZO Procedures2904. 10-Meter Firing2905. Transition Firing

    List of Figures

    2-1 The SAW (Left and Right Sides)2-4 Five Main Groups (General Assembly)2-3 Safety2-5. Clearing Procedures2-2. Front and Rear Sights2-6. Removing the Operating Group2-7. Removing the Barrel Group2-8. Removing the Buttstock and Buffer Group2-9. Removing the Trigger Group2-10. Replacing the Trigger Group2-11. Replacing the Buttstock and Buffer Group2-12. Replacing the Barrel Group2-13. Replacing the Operating Group2-14. Separating the Operating Group

    2-15 Operating Group, Detailed Disassembled2-16 Removing the Heat Shield2-17 Removing the Collar2-18 Removing the Gas Regulator2-19 Barrel Group, Detail Disassembled2-21 Removing the Handguard2-22 Removing the Gas Cylinder2-20 Replacing the Collar2-23 Removing the Bipod2-24 Receiver Group, Detail Disassembled2-25 Replacing the Gas Cylinder2-26 Malfunctions2-27 Stoppages2-28 Lowering the Bipod

  • Machine Guns and Machine Gun Gunnery ____________________________________________________________________ 2-3

    2-29 Folding of Bipod Under the Handguard2-30 Spare Barrel Bag2-31 Mounting the Bracket and the Device2-32 Centered Reticle Pattern2-33 Reticle Aiming Point and the Target

    Aiming Point2-34 SAW Tool Storage2-35 Cleaning the Gas Vent Hole2-36 Cleaning the Central Hole2-37 Cleaning the Grooves of the Body2-38 Cleaning the Front Interior and Internal

    Grooves of the Gas Cylinder2-39 Cleaning the Grooves of the Piston2-40 Cleaning the Hole in the Front of the Piston2-41 Cartridges for the SAW2-42 Cartridges in Metallic Belt2-43 Ballistic Data for 5.56mm Ammunition2-44 Condition Codes for the SAW2-45 Loading2-46 Loading an Ammunition Belt

    2-47 Loading a Magazine2-48 Prone Position, Bipod-Supported2-49 Firing From the Hip (Preferred Assault

    Fire Technique)2-50 Firing From Under the Arm2-51 Sight Picture2-52 Sliding Scale on Sight2-53 Windage and Elevation (Peep Sight)

    Correction Chart2-54 Zero Group Size2-56 Grid Square Overlay2-55 Basic Machine Gun Target2-57 Shot Group on Basic Machine Gun Target2-58 Overlay Placed Over Pasters2-59 Common Errors of Marksmanship2-60 Firing Table I2-61 Firing Table II2-62 Single E-Type and Double E-Type

    Silhouette Targets

  • Chapter 2

    MACHINE GUN, LIGHT, SQUAD AUTOMATIC WEAPON, M249

    Section 1Introduction

    The machine gun, light, squad automatic weapon,M249 (SAW) is a gas-operated, air-cooled, belt ormagazine-fed, automatic weapon that fires from theopen-bolt position (see figure 2-1). It has a maximumrate of fire of 850 rounds per minute. Primarily,ammunition is fed into the weapon from a 200-roundammunition box containing a disintegrating metallicsplit-link belt. As an emergency means of feeding, the

    SAW can use a 20 or 30 round M16 rifle magazine,but this will increase the chance of stoppages.

    The SAW can be fired from the hip, or underarmusing assault fire techniques; however, the preferredmethod of employment is to fire from the bipod-stead-ied position. The bipod gives the weapon the stabilityneeded to engage targets at its maximum effectiverange. The SAW has a spare barrel to allow quick bar-rel changes during employment; however, barrelsmust not be interchanged with those from other SAWsunless the headspace has been set for that weapon by

    Figure 2-1. The SAW (Left and Right Sides).

  • 2-6 ____________________________________________________________________________________________________ MCWP 3-15.1

    ordnance personnel. Each automatic rifleman andassistant automatic rifleman should have ready accessto TM 08671A-10/1A, a detailed, pocket-sized refer-ence manual for operators of the SAW.

    2101. General Data

    Weight of SAW:With bipod and tools. . . . . . . . . . . . . . . . . . . . . . . . . . . 17 poundsWith 200 round drum . . . . . . . . . . . . . . . . . . . . . . . . 23.92 pounds

    Measurements:Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40.87 inchesMuzzle velocity

    Ball ammunition . . . . . . . . . . . . . . . 3,025 feet per secondTracer ammunition . . . . . . . . . . . . . 2,870 feet per second

    Rifling . . . . . . . . . Standard right hand twist one turn in 7 inches

    Ranges:Maximum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3,600 metersMaximum effective

    Point targets . . . . . . . . . . . . . . . . . . . . . . . . . . .800 metersArea targets . . . . . . . . . . . . . . . . . . . . . . . . . . 1,000 meters

    Grazing fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .600 meters

    Ammunition:Caliber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.56 milimeterTypes in use . . . . . . . . . . . . . . . . .Ball, tracer, blank, and dummyBasic allowance . . . . . . . . . . . . .600 rounds per SAW, carried by

    the automatic rifleman andassistant automatic rifleman

    Weight of full 200 round drum . . . . . . . . . . . . . . . . . . 6.92 pounds

    Rates of fire:Sustained . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 rounds per minute,

    fired in 3 to 5 round bursts,4 to 5 seconds between bursts

    no barrel changes

    Rapid . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 rounds per minute,fired in 6 to 8 round bursts,

    2 to 3 seconds between bursts,barrel change every 2 minutes

    Cyclic . . . . . . . . . . . . . . . . . . . . . . . . . . . 850 rounds per minute,continuous burst,

    barrel change every minute

    2102. Sights

    The SAW has a hooded and semi-fixed front sight(see figure 2-2A). The rear sight assembly (see fig-ure 2-2B) mounts on the top of the cover and feedmechanism assembly. The elevation knob drum hasrange settings from 300 meters to 1,000 meters.Range changes are made on the SAW sight by rotat-ing the elevation knob to the desired range setting.Rotation of the rear sight aperture (peep sight) isused for fine changes in elevation or range adjust-ments, such as during zeroing. Each click of the peepsight (180-degree turn) equals a one-half-mil changein elevation, which is .5 cm at 10 meters. The sightadjusts for windage by rotating the wind- age knob.Each click of windage adjustment also equals a one-half-mil change, which is .5 cm at 10 meters. Thereis also a windage sliding scale marked with indexlines for centering the rear sight aperture.

    2103. Safety

    The safety (figure 2-3) is in the trigger housing. Thesafety is pushed from left to right (red ring NOT visi-ble) to render the weapon SAFE, and the bolt cannotbe released to go forward. The safety is pushed fromright to left (red ring visible) to render the weaponready to fire. The cocking handle on the right side ofthe weapon is used to pull the bolt to the rear.

    2104. Roles of the SAW

    From the mid-1960s to the mid-1980s the MarineCorps operated with an automatic weapon at thesquad/fire team level that was extremely limited. Theautomatic riflemans weapon (the M16A1) was thesame weapon carried by the other members of the fireteam. The automatic rifleman had no unique capabili-ties or equipment except that he was given a remov-able, clip on bipod for his weapon. This shortfallwas remedied with the introduction of the SAW in thelate 1980s. The Marine Corps has never had a morecapable and versatile weapon at the squad level. Priorto the fielding of the SAW, the Browning automatic

  • Machine Guns and Machine Gun Gunnery ____________________________________________________________________ 2-7

    rifle had been the last automatic weapon used by theCorps that provided significant fire power to the riflesquad beyond the capabilities of the other small armscarried within it. Various models of the Browningautomatic rifle were used by Marine units from WorldWar I to the early 1960s. Even the much respectedBrowning automatic rifle, that served the Corps sowell for over 40 years, had limitations that the designof the SAW has overcome. The Browning was anautomatic rifle and it had some design limitationscommon to other rifles of its day. These included alimited ammunition supply (only a 20 round box mag-azine), problems with overheating during continuousfiring (because of a fixed barrel that could not bechanged by the operator), and a limited maximumeffective range.

    Although employed as an automatic rifle by theMarine Corps, the SAW is designed like a mediummachine gun. As such it has design features that makeit a more versatile weapon, such as; it can be belt ormagazine fed thus providing more continuous firebefore reloading and it has a quick change barrel fea-ture which allows barrel changes during periods ofcontinuous firing without taking the weapon out ofaction for more than a few seconds. The SAW alsohas greater effective range and a higher rate of firethan any other weapon in the present rifle squad.

    The SAW can provide a heavy volume of continuous,accurate fire in support of offensive or defensive oper-ations. Its presence in large numbers (e.g., nine perrifle platoon) at the small unit level has significantlyincreased the combat power of those units. In the past,medium machine guns were often attached to platoonsor squads, more out of concern over the lack of firepower in those small units than for sound tactical rea-sons. The introduction of the SAW into those unitshas changed that. The SAW provides the platoonswith significant fire power against enemy personneland light equipment. Because of this, more times thannot, the companys machine gun section can now beemployed as a section, in a general or direct supportrole, rather than attached out. The SAWs presence, inany type of unit, increases the available fire power

    and provides additional flexibility to the unit leader interms of weapons employment options.

    Section 2Disassembly and Assembly

    The SAW is designed for easy disassembly and assem-bly; the use of force is not necessary and no specialtools are required. As the weapon is disassembled,place the parts (in the order in which they are removed)on a clean, flat surface. This reduces the possibility oflosing a part and aids in assembly, as all parts arereplaced in reverse order. To prevent unnecessary wear,disassembly should be kept to the minimum, consistentwith maintenance and training requirements.

    Disassembly and assembly may be divided into twocategories; general and detailed. General disassemblyinvolves separation of the weapon into main groups.This is also known as field stripping and is a practicethat stems from past experience in combat situations.The intent behind designating main groups for aweapon and the practice of field stripping is to allowthe operator to quickly break the weapon down into aset of major components that can be hastily cleaned tokeep the weapon ready for action. The idea is to disas-semble the weapon just far enough to conduct basiccleaning without having to contend with numerousassemblies and parts.

    Detailed disassembly, for the operator, involves theremoval of some of the component parts and assem-blies from the main groups. The idea here is that,when the situation and conditions permit, the opera-tor can then take the time to more fully disassembleand thoroughly clean the weapon. Complete generaland detailed disassembly is normally the expectedroutine in garrison after the completion of firing and/or field training, but this may also be conducted in afield environment when necessary, to ensure theproper functioning and maintenance of the weapon.Disassembly of the weapon beyond that described inthis publication is not authorized, except by qualifiedordnance personnel.

  • 2-8 ____________________________________________________________________________________________________ MCWP 3-15.1

    Figure 2-2. Front and Rear Sights.

    Figure 2-3. Safety.

  • Machine Guns and Machine Gun Gunnery ____________________________________________________________________ 2-9

    2201. General Disassembly

    General disassembly is the separation of the SAWinto five main groups (see figure 2-4). They are theoperating group, the barrel group, the trigger group,the buttstock and buffer group, and the receiver group.

    a. Clearing the Weapon. The first step in disas-sembly is to clear the weapon (see figure 2-5). Thisapplies in all situations, not just after firing. The auto-matic rifleman must always assume the SAW is loaded.To clear the SAW, perform the following procedures:

    Move the safety to the FIRE position by pushing itto the left until the red ring is visible.

    With the right hand, palm up, pull the cocking han-dle to the rear, locking the bolt in place.

    While holding the resistance on the cocking handle,move the safety to the SAFE position by pushing itto the right until the red ring is not visible. (Theweapon cannot be placed on safe unless the bolt islocked to the rear.)

    Return and lock the cocking handle in the forwardposition.

    CAUTIONWhen opening the feed cover, make sure the weaponis on the ground away from your face. With the weap-on on your shoulder, possible injury could occur if around goes off when the cover is raised.

    Raise the cover and feed mechanism assembly andconduct the five-point safety check for brass, links,or ammunition.1. Check the feed pawl assembly under the feed

    cover.2. Check the feed tray assembly.3. Lift the feed tray assembly and inspect the

    chamber.4. Check the space between the bolt assembly and

    the chamber.5. Insert two fingers of the left hand in the

    magazine well to extract any ammunition orbrass.

    Close the cover and feed mechanism assembly andmove the safety to the FIRE position. With the righthand, palm up, return the cocking handle to the rearposition. Press the trigger and at the same time easethe bolt forward by manually riding the cockinghandle forward.

    Figure 2-4. Five Main Groups (General Assembly).

  • 2-10 ___________________________________________________________________________________________________ MCWP 3-15.1

    Figure 2-5. Clearing Procedures.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-11

    Figure 2-5. Clearing ProceduresContinued.

  • 2-12 ___________________________________________________________________________________________________ MCWP 3-15.1

    b. Removing the Operating Group. Once theweapon is clear, general disassembly begins byremoving the operating group. The operating groupconsists of the spring guide rod, operating rod spring,slide assembly, piston assembly, and bolt assembly.

    To remove the operating group, first pull the upperretaining pin at the rear of the receiver that holdsthe buttstock to the left. Allow the buttstock topivot downward and place it on a surface to supportthe weapon for disassembly. See figure 2-6, step 1.

    To release the operating rod assembly from thepositioning grooves inside the receiver, hold theweapon with one hand on the buttstock assemblyand use the thumb of the other hand to push in andupward on the rear of the operating rod assembly.

    Pull the operating rod and spring from the receivergroup and separate the parts. See figure 2-6, step 2.

    Hold the buttstock assembly with the left hand tostabilize the weapon. With the right hand, pull thecocking handle to the rear to lock the bolt. Returnthe cocking handle to the forward position. Place a

    Figure 2-6. Removing the Operating Group.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-13

    finger on the face of the bolt and push until the fin-ger makes contact with the bridge at the end of thereceiver. This leaves the piston, slide, and boltassemblies exposed.

    Hold the slide assembly while pulling the movingparts out the rear of the receiver. See figure 2-6,step 3.

    c. Removing the Barrel Group. The barrel groupconsists of barrel, heat shield, flash suppressor, frontsight, gas regulator, and gas regulator collar. See fig-ure 2-7.

    CAUTIONBarrels must not be interchanged with those from oth-er SAWs unless the headspace has been certified forthat weapon by ordnance personnel.

    To remove the barrel from the receiver, close thecover and feed mechanism assembly, depress thebarrel locking lever with the left hand, lift the carry-ing handle using the right hand, and push the barrelforward.

    d. Removing the Buttstock and Buffer Group.To remove the buttstock and buffer assembly (see fig-ure 2-8), use a cartridge or the spring guide rod topush the lowermost retaining pin on the rear of the

    receiver to the left. It is a captured pin; it is notremoved. Remove the buttstock and shoulder assem-bly by pulling it rearward, while supporting the trig-ger mechanism.

    e. Removing the Trigger Group. To separate thetrigger group, push the lowermost retaining pin thatwas used to release the buttstock all the way to the leftand remove the trigger assembly from the bottom ofthe receiver. See figure 2-9.

    CAUTIONThe upper and lower retaining pins in the rear of thereceiver are captured pins. Do not attempt to removethem completely.

    Once the trigger group has been removed general dis-assembly is complete.

    2202. General Assembly

    The SAW is assembled in reverse order of thedisassembly.

    a. Replacing the Trigger Group. Align the trig-ger mechanism with the slot on the bottom of the

    Figure 2-7. Removing the Barrel Group.

    Figure 2-8. Removing the Buttstock andBuffer Group.

  • 2-14 ___________________________________________________________________________________________________ MCWP 3-15.1

    receiver. Hold the trigger mechanism in position toaccomplish the next step. See figure 2-10.

    b. Replacing the Buttstock and Buffer Group.Align the lower hole in the buttstock and buffer groupwith the rear hole in the trigger mechanism, then pushthe lower retaining pin to the right. See figure 2-11.

    c. Replacing the Barrel Group. Depress the bar-rel locking lever to the rear with the left hand, whileholding the carrying handle with the right hand. Pullthe barrel rearward and push downward; align the gasregulator with the gas cylinder and lock it by releasingthe barrel locking lever. Check the barrel to ensure it

    is locked into the receiver by pulling or lifting on thecarrying handle. See figure 2-12.

    d. Replacing the Operating Group

    Open the cover assembly on the receiver. Insert theface of the piston into the receiver, aligning the boltlugs onto the receiver rails. Pull the trigger andpush the moving parts forward until the bolt isseated into the chamber.

    Figure 2-9. Removing the Trigger Group

    Figure 2-10. Replacing the Trigger Group.Figure 2-11. Replacing the Buttstock and

    Buffer Group.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-15

    Place the operating rod tip into the operating rodspring. Then, insert the free end of the operatingrod and spring into the rear of the piston. Depressthe rear of the operating rod assembly until the twolugs on the buffer are positioned in the receivergrooves. See figure 2-13.

    Pivot the buttstock upward into position and pushthe upper retaining pin to the right, locking thebuttstock to the receiver.

    e. Conducting a Function Check. A functioncheck must be performed to ensure that the SAW hasbeen assembled correctly. The procedures, in order,are

    Grasp the cocking handle with the right hand, palmup, and pull the bolt to the rear locking it in place.

    While continuing to hold the resistance on thecocking handle, use the left hand to move the safetyto the SAFE position.

    Push the cocking handle forward into the forwardlock position.

    Pull the trigger. (The weapon should not fire.)

    Grasp the cocking handle with the right hand, palmup, and pull and hold it to the rear.

    Move the safety to the FIRE position.

    While continuing to hold resistance on the cockinghandle, use the left hand to pull the trigger and easethe bolt forward to prevent it from slamming intothe chamber area and damaging the face of the bolt.

    Figure 2-12. Replacing the Barrel Group.

    Figure 2-13. Replacing the Operating Group.

  • 2-16 ___________________________________________________________________________________________________ MCWP 3-15.1

    If the weapon fails the function check, check formissing parts or the reassembly procedures. (Beforedisassembling the weapon, make sure it is posi-tioned where the guide rod and spring cannot causebodily harm if the bolt is locked to the rear.)

    CAUTIONThe bolt must be eased forward to prevent damage tothe cover and feed mechanism assembly and operatingrod group. This is known as riding the bolt forward.

    NOTEThe cover and feed mechanism assembly can beclosed with the bolt in either the forward or therearward position.

    2203. Detailed Disassembly and Assembly

    The term detailed disassembly, as it is used in thismanual, refers only to those disassembly procedures

    authorized for the operator level. This is not to beconfused with procedures authorized for 2d echelonmaintenance (unit armorers) or above. Detailed disas-sembly of any of the groups beyond that described inthis document is NOT AUTHORIZED except byqualified ordnance personnel.

    The operator is not authorized to detail disassemblethe trigger group or the buttstock and buffer group.The other three groups can be further disassembled bythe operator as described below:

    a. Operating Group

    (1) Detailed disassembly

    To separate the operating group (see figure 2-14),hold the piston assembly in one hand, place theother hand on the bolt assembly, and rotate the boltto disengage the bolt from the slide assembly.

    To separate the slide assembly from the piston,press the retaining pin at the rear of the slideassembly to the left and lift the slide assembly.

    Figure 2-14. Separating the Operating Group.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-17

    This completes detailed disassembly of the operat-ing group. See figure 2-15.

    (2) Detailed assembly

    Hold the piston in one hand with the face of thepiston facing outward and the sear notches down-ward. With the other hand, place the slide assemblyonto the rear of the piston with the firing pintoward the front of the piston. (Check the slideassembly retaining pin to make sure it is out.)

    Push the slide assembly retaining pin to the right.This locks the piston assembly and the slide assem-bly together.

    Place the bolt on the slide assembly, aligning thedriving lug of the bolt with the slot of the slideassembly. Apply pressure to the face of the bolt tocompress the firing pin spring. Then, rotate the boltto hook the driving lug into the slide assembly.

    b. Barrel Group

    (1) Detailed disassembly To remove the heat shield, place the barrel with the

    muzzle end on a hard, flat surface with the heatshield facing away from the body. Place the indexfingers of each hand inside the chamber. Use thethumbs to push up on the top clip. See figure 2-16.

    Figure 2-15. Operating Group, Detailed Disassembled.

    Figure 2-16. Removing the Heat Shield.

  • 2-18 ___________________________________________________________________________________________________ MCWP 3-15.1

    To remove the gas regulator and collar, rotate thegas collar pin out of the notch. Place the tip of thescraper with the concave side facing the pin of thecollar inside the notch. (Be careful not to use toomuch pressure, so as not to break the tip of thescraper.) Rotate the collar counterclockwise over

    the concave portion of the tip on the scraper andpast the notch until the collar slides off. See figure2-17.

    To remove the gas regulator (see figure 2-18), sep-arate it from the gas block. This completes detaileddisassembly of the barrel group. See figure 2-19.

    Figure 2-17. Removing the Collar.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-19

    (2) Detailed assembly

    Insert the gas regulator into the gas block and alignthe notch on the gas regulator with the notch of thegas block.

    With the gas regulator installed and supported on afirm surface, place the gas regulator collar onto theprotruding end of the body and align the springwith the stud. Push the gas regulator collar firmlydownward and rotate it until it slips into place.Then, press it in and rotate it to lock it in place. Seefigure 2-20, page 2-20.

    Replace the heat shield by placing the hook end ofthe heat shield under the front sight post and pressdown until the clamps lock on the barrel.

    c. Receiver Group

    (1) Detailed disassembly Removing the handguard. The handguard assembly

    consists of the handguard, handguard retaining pin,and cleaning equipment retaining clip. Push thehandguard retaining pin to the left using a length ofcleaning rod (see figure 2-21, step 1, page 2-21);then pull the handguard down (see figure 2-21, step2, page 2-21).

    CAUTIONThe handguard retaining pin is a captured pin. Do notattempt to remove it completely.

    Removing the gas cylinder. To remove the gas cyl-inder from the receiver (see figure 2-22, page 2-22), grasp the gas cylinder at the top of the bipodlegs, turn it to the left or right to release the lockingspring, and then pull it away from receiver.

    Removing the bipod. Once the gas cylinder isremoved, remove the bipod (see figure 2-23, page2-22) by pulling it away from the receiver. Thiscompletes detailed disassembly of the receiver. Seefigure 2-24, page 2-23.

    Figure 2-18. Removing theGas Regulator.

    Figure 2-19. Barrel Group, Detail Disassembled.

  • 2-20 ___________________________________________________________________________________________________ MCWP 3-15.1

    (2) Detailed assemblyReplacing the bipod. Place the bipod on the receivergroup with the bipod legs open and pointed down-ward. See figure 2-23, page 2-22.

    Replacing the gas cylinder. Push the gas cylinderthrough the bipod yoke into the receiver. Push the cyl-inder to the rear while countering the pressure of thelocking spring and guiding the end of the cylinder intothe receiver with the other hand applying downwardpressure. Position the recess in the cylinder near thespring. Turn the cylinder until the spring clicks into therecess at the rear of the gas cylinder. See figure 2-25.

    Replacing the handguard. To replace the handguard,place it on the receiver from the bottom and push it tothe rear until it stops. Using the guide rod, push thehandguard retaining pin to the right, which locks thehandguard into position. Push the handguard down tomake sure it is locked. See figure 2-21.

    Section 3Functioning

    The cycle of functioning is broken down into eightbasic steps. These steps are feeding, chambering,locking, firing, unlocking, extracting, ejection, andcocking. More than one step may occur simulta-neously during the cycle of functioning. By under-standing how the SAW functions, it will be easier torecognize and correct malfunctions and stoppageswhich occur during firing.

    The cycle is started by putting the first round of thebelt in the tray groove or by inserting the magazineinto the magazine well. Then the trigger is pulled,releasing the sear from the sear notch. When the trig-ger is pulled to the rear, the rear of the sear is low-ered and disengaged from the sear notch. This allowsthe piston and bolt to be driven forward by theexpansion of the operating rod spring. The cyclestops when the trigger is released and the sear againengages the sear notch on the piston. The sequenceof functioning is as follows:

    2301. Feeding

    As the bolt starts its forward movement, the feed leveris forced to the right, causing the feed-pawl assemblyto turn in the opposite direction. This forces the feed-pawl assembly over the next round in the belt, and itis ready to place the next round into the tray groovewhen the rearward action occurs again. As the boltmoves to the rear after firing, the feed roller forces thefeed lever to the left. The feed lever is forced to turn,moving the feed pawl to the right. This places a roundin the tray groove.

    2302. Chambering

    As the bolt travels forward, the upper locking lugengages the rim of the round. The pressure of thefront and rear cartridge guides holds the round so that

    Figure 2-20. Replacing the Collar.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-21

    positive contact is made with the upper locking lug ofthe bolt. The front cartridge guide prevents forwardmovement of the link as the round is stripped from thebelt. The upper locking lug carries the round forward.The chambering ramp causes the nose of the round tobe crammed downward into the chamber. When theround is fully seated in the chamber, the extractorsnaps over the rim of the round, and the ejector onthe rail inside the receiver is depressed.

    2303. Locking

    As the round is chambered, the bolt enters the barrelsocket. The upper and lower locking lugs contact thebolt camming surfaces inside the barrel and start turn-ing the bolt clockwise. The action of the bolt into theslide assembly, as the piston continues forward, turnsthe bolt to complete its 90 degree (one-quarter turn)clockwise rotation. Locking is now complete.

    Figure 2-21. Removing the Handguard.

  • 2-22 ___________________________________________________________________________________________________ MCWP 3-15.1

    2304. Firing

    After the bolt is fully forward and locked, the pistoncontinues to go forward, independent of the bolt, for ashort distance. The slide assembly carries the firingpin through the face of the bolt. The firing pin strikesthe primer of the round and the primer fires the round.

    2305. Unlocking

    After the round is fired and the bullet passes the gasport, part of the expanding gases go through the gasplug into the gas regulator. The rapidly expandinggases enter into the gas cylinder from the gas regula-tor, forcing the piston to the rear. As the piston contin-

    ues to the rear, the slide assembly, also moving to therear, causes the bolt to begin its counterclockwiserotation. The upper and lower locking lugs of the boltcontact the bolt camming surfaces inside the barrelsocket and, as the bolt continues toward the rear, itcompletes a one-quarter turn counterclockwise. Therotation and movement to the rear unlocks the boltfrom the barrel socket.

    2306. Extracting

    Extracting begins during the unlocking cycle. Therotation of the bolt loosens the cartridge case in thechamber. As the piston and bolt move to the rear, theextractor pulls the cartridge case from the chamber.

    Figure 2-22. Removing the Gas Cylinder.

    Figure 2-23. Removing the Bipod.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-23

    2307. Ejecting

    As the cartridge case is pulled from the chamber, thebolt passes by the ejector. This causes the ejector clipto expand, forcing the ejector to push the expendedcartridge. The extractor grips the right side of the car-tridge and causes it to spin from the weapon as itreaches the ejection port. The empty belt links areforced out the link ejection port as the rearward move-ment of the bolt causes the next round to be posi-tioned in the tray groove.

    2308. Cocking

    The piston assembly acts against the firing pin, pullingthe firing pin from the primer of the spent cartridgecase. The action of the piston assembly, continuing tothe rear with the firing pin, releases the compression ofthe firing pin spring. As long as the trigger is held tothe rear, the SAW will continue to complete the eightsteps of functioning automatically. When the trigger isreleased and the sear again engages the sear notch, the

    Figure 2-24. Receiver Group, Detail Disassembled.

    Figure 2-25. Replacing the Gas Cylinder.

  • 2-24 ___________________________________________________________________________________________________ MCWP 3-15.1

    cycle of functioning is stopped and the weapon iscocked. To prevent undue wear to the sear and searnotch, the automatic rifleman must hold the triggerfirmly to the rear during firing.

    Section 4Malfunctions and Stoppages

    Automatic riflemen must have a detailed understand-ing of the many component parts of their weapon,what those parts do during functioning, and whatmechanical problems may be encountered during fir-ing. This knowledge ensures that those problems canbe assessed quickly and corrective action taken.

    2401. Malfunctions

    A malfunction is a failure of the gun to function satis-factorily; the gun will fire, but fires improperly.Defective ammunition or improper operation of thegun by a crew member is not considered a malfunc-tion. Two of the more common malfunctions are slug-gish operation and runaway gun.

    a. Sluggish Operation. Instead of firing at itsnormal rate, a sluggish gun fires very slowly. It can bedue to excessive friction or loss of gas. Excessive fric-tion is usually due to lack of lubrication or excessivedirt/carbon in the gas system or on the bolt and

    receiver rails. Excessive loss of gas is usually due toloose connections in the gas system. The action takento reduce sluggish operation is to move the regulatorsetting to the high position. The remedy for continuedsluggish operation is to clean, lubricate, tighten, orreplace parts as required.

    b. Runaway Gun. This is the case when a guncontinues to fire after you have released the trigger;firing is uncontrolled. A runaway gun is usuallycaused by a worn, broken, or burred sear; the searshoulder is unable to grab the operating rod and holdit to the rear. An excessively worn sear notch on theoperating rod could also be responsible. To stop a run-away gun, the automatic rifleman or the assistantautomatic rifleman twist and break the belt of ammu-nition. The remedy for runaway gun is to replaceworn parts.

    Further information on these two malfunctions islisted in figure 2-26.

    2402. Stoppages

    A stoppage is any interruption in the cycle of function-ing caused by faulty action of the weapon or defectiveammunition. Stoppages are classified by their relation-ship to the cycle of functioning. Figure 2-27 showstypes of interruptions or stoppages, their probablecauses, and the corrective actions. Stoppages must be

    Figure 2-26. Malfunctions.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-25

    reduced quickly and the weapon returned to action.Apply immediate action. (See paragraph 2403 below.)

    2403. Immediate Action

    Immediate action is that action taken by the auto-matic rifleman to reduce a stoppage, without investi-gating its cause, and quickly return the weapon toaction. Two terms used to describe ammunition condi-tion should be understood in conjunction with imme-diate action procedures.

    A hang fire occurs when the cartridge primer has det-onated after being struck by the firing pin but someproblem with the propellant powder causes it to burntoo slowly and this delays the firing of the projectile.Time (5 seconds) is allotted for this malfunctionbefore investigating a stoppage further because injuryto personnel and damage to equipment could occur ifthe round went off with the cover of the weapon open.

    A cook off occurs when the heat of the barrel is highenough to cause the propellant powder inside theround to ignite even though the primer has not beenstruck. Immediate action is completed in a total of 10seconds to ensure that the round is extracted prior tothe heat of the barrel effecting it. When the round failsto extract/eject, further action is delayed (15 minutes)if the barrel is hot because the gunner must assumethat a round is still in the chamber and could cook offat any time prior to the barrel cooling off.

    The immediate action procedures for the SAW are

    Wait 5 seconds after the misfire to guard against ahang fire.

    Within the next 5 seconds (to guard against a cookoff) pull and lock the cocking handle to the rearwhile observing the ejection port to see if a car-tridge case, belt link, or round is ejected. Ensurethat the bolt remains to the rear to prevent doublefeeding if a round or cartridge case is not ejected.

    If a cartridge case, belt link, or a round is ejected,push the cocking handle to its forward position,take aim on the target, and press the trigger. If theweapon does not fire, take remedial action. If a car-

    tridge case, belt link, or round is not ejected, takeremedial action.

    2404. Remedial Action

    Remedial action is any action taken to determine thecause of a stoppage and to restore the weapon to anoperational condition. This action is taken only afterimmediate action did not remedy the problem. Seefigure 2-27.

    a. Cold Weapon Procedures. When a stoppageoccurs with a cold weapon and immediate action hasfailed, use the following procedures:

    While the weapon is on the shoulder, grasp thecocking handle with the right hand, palm up, pullthe cocking handle to the rear locking the bolt.While holding the resistance on the cocking handle,move the safety to SAFE and return the cockinghandle forward.

    Place the weapon on the ground or away from theface, open the feed cover, and perform the five-point safety check (page 2-9). Reload and continueto fire.

    If it does not fire, clear the weapon and inspect itand the ammunition.

    b. Hot Weapon Procedures. If the stoppageoccurs with a hot weapon (200 or more rounds in 2minutes or less), move the safety to SAFE, let theweapon cool for 15 minutes, and use the same proce-dures as outlined for cold weapon procedures.

    WARNING

    If nothing is ejected and the barrel is hot(200 or more rounds fired in 2 minutes orless), do not open the cover. Push thesafety to the right (red ring not visible),which places the weapon on SAFE. Keepthe weapon pointed downrange and re-main clear for 15 minutes, then clear theweapon.

  • 2-26 ___________________________________________________________________________________________________ MCWP 3-15.1

    Figure 2-27. Stoppages.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-27

    Section 5Mounts and Accessories

    The SAW is best employed using the bipod for sup-port. The bipod provides a stable platform that bestenables the automatic rifleman to accurately engagetargets at the maximum effective range of the weapon.In some situations, however, it may be necessary toemploy the weapon using assault fire techniques. Seesection 8, Operation and Firing, of this chapter formore detail.

    2501. Bipod

    The bipod is used to fire from the prone position orfrom a fighting hole. The shoulder rest on thebuttstock provides support for the SAW when fired inthe bipod mode. The gas cylinder holds the bipod inplace. Once the gas cylinder is removed, the bipod canalso be removed from the receiver.

    To lower the bipod legs, hold the legs together andpull down and away from the handguard. Releasethe legs so that they lock in the vertical position. To

    extend the bipod legs, grasp the foot of each legand pull down. See figure 2-28.

    To retract the bipod legs, push in the latches andpush in the legs.

    Fold the bipod legs when transporting the weapon.Hold the two legs together, pull back under thehandguard, and release so that the hooks on thelegs grip the handguard. The bipod can be foldedonly when the legs are in the closed position. Seefigure 2-29.

    2502. Spare Barrel Bag

    The spare barrel bag is used to carry a spare barrel foreach SAW. It has an attached carrying strap and zip-pered exterior pocket for carrying additional cleaninggear or accessories. See figure 2-30.

    2503. Night Vision Sights

    The principal night vision sight used with the SAW isthe AN/PVS-4.

    a. Zeroing the AN/PVS-4. Zeroing aligns theAN/PVS-4 to the SAW. The sight may be zeroedduring daylight or darkness. (TM 11- 5855-238-10.) To obtain a precise zero, it is best done at 300meters and at night. If done during daylight, thedaylight cover must be used. Once an AN/PVS-4has been zeroed on an SAW, anyone who knowshow to use the reticle should fire the weapon effec-tively. However, there may be some changes inzero when the objective focus is adjusted to engagetargets at various ranges and when the diopter focusis adjusted for the vision of different firers. A metaltarget is excellent for zeroing purposes, because thestrike of the round can be easily observed with anAN/PVS-4.

    CAUTIONWhen mounting an AN/PVS-4 to the mounting brack-et, make sure that the hole for the screw in the AN/PVS-4 is aligned and flush against the bracket screw.If not, the screw will strip the threads in the screw holeof the AN/PVS-4 and prevent use with the SAW.

    Figure 2-28. Lowering the Bipod.

  • 2-28 ___________________________________________________________________________________________________ MCWP 3-15.1

    b. Mounting the Bracket and the Device

    Place the mounting bracket on top of the feed covermechanism assembly so that the two forked endsare secured around the headless pins.

    Remove the screw cover behind the rear sightassembly, and screw the bracket knob in until it istight.

    Position the AN/PVS-4 on top of the bracket sothat the mount of the AN/PVS-4 is aligned with themounting knob of the bracket.

    Turn the mounting knob clockwise until the AN/PVS-4 is tight. See figure 2-31.

    c. Seating the Device. Once the device ismounted, the automatic rifleman fires a three-round

    burst to seat the device, checks and tightens themounting knob, and then fires another three-roundburst. He checks the device to ensure it is settled andsecurely fastened and tightens the mounting knob, ifnecessary. He does not fire at the boresight target dur-ing this procedure.

    d. Centering the Reticle in the Field of View. Theautomatic rifleman turns the device on and centers thereticle pattern in the field of view by using the azimuthand elevation actuators. To be accurate, he does this byrotating the elevation and azimuth actuators from oneside to the other and from top to bottom while countingthe number of clicks. (The elevation actuator has thedown direction marked DN with an arrow. This movesthe strike of the round. The azimuth actuator has the

    Figure 2-29. Folding of Bipod Under the Handguard.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-29

    right direction marked with RT with an arrow. This alsomoves the strike of the round. He divides the number ofclicks for each by two and moves the elevation and azi-muth actuators that number of clicks. This manuallycenters the reticle in the field of view horizontally andvertically. This enables the automatic rifleman to reachan accurate boresight between the point of aim (reticle)and the center of the bore. See figure 2-32.

    e. Confirming the Boresight. To do this, the auto-matic rifleman centers and affixes a 25-meter (M16A2)zero target to the back of a basic machine gun paster tar-get. This provides a large, clear surface for identifying thestrike of the round. Then, he emplaces the target 10meters from the firing position. The automatic riflemanplaces the reticle aiming point on the 25-meter zero tar-get aiming point (see figure 2-33, page 2-32). and fires asingle round. If the round impacts anywhere near the aim-ing point, he fires two more rounds to establish his group.

    Section 6Maintenance

    Proper maintenance, care, cleaning, and inspec-tion of a weapon and its accessories determinewhether or not it will function correctly whenneeded. The bore and chamber must be properlymaintained to preserve accuracy. Because of theclose fit of working surfaces and the high speed atwhich the gun operates, the receiver and all mov-ing parts must be kept clean, correctly lubricated,and free from burrs, rust, and dirt to ensure proper,efficient functioning.

    There are cer ta in act ions that must be takenbefore, during, and after firing to properly main-tain the SAW.

    Figure 2-30. Spare Barrel Bag.

  • 2-30 ___________________________________________________________________________________________________ MCWP 3-15.1

    Figure 2-31. Mounting the Bracket and the Device.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-31

    2601. Care and Cleaning Before, During, and After Firing

    a. Before Firing

    Wipe the bore dry.

    Inspect the weapon as outlined in the operatorstechnical manual.

    Lubricate the weapon.

    b. During Firing

    Inspect the weapon periodically to ensure that itremains lubricated.

    When malfunctions or stoppages occur, follow theprocedures in section 4.

    c. After Firing

    Immediately clear and clean the weapon. Every 90 days during inactivity, clean and lubricate

    the weapon unless inspection reveals more frequentservicing is necessary.

    2602. Normal Maintenance Procedures

    The SAW should be cleaned immediately after fir-ing. It should be detail disassembled before cleaning.After it has been cleaned and wiped dry, a thin coatof CLP is applied by rubbing with a cloth. Thislubricates and preserves the exposed metal parts dur-ing all normal temperature ranges. When not in use,the SAW should be inspected daily and cleaned andlubricated when necessary.

    Figure 2-32. Centered Reticle Pattern.

  • 2-32 ___________________________________________________________________________________________________ MCWP 3-15.1

    a. Cleaning. Cleaning material authorized for useon the SAW by the operator is CLP, RBC, and drycleaning solvent. Use CLP or RBC for daily mainte-nance and to remove minor carbon buildup after fir-ing. Dry cleaning solvent will dry out the metal and isrecommended for cleaning when changing from onetype of lubricant to another.

    The special tool, scraper, is used to clean the gas sys-tem. Just as its name implies it is used to scrape car-bon buildup out of the various ports, grooves andrecesses of the gas cylinder, piston, block, and collar.See the text below for details. This tool is carried inthe handguard along with the other SL-3 cleaningcomponents for the weapon. See figure 2-34.

    All metal components and surfaces that have beenexposed to powder fouling should be cleaned usingCLP on a bore-cleaning patch. The same procedure isused to clean the receiver.

    CAUTIONWhen using CLP, no other type cleaner can be used.Never mix CLP with RBC or LSA.

    (1) Bore and chamber. Use CLP and fresh swabs.

    (2) Gas regulator. Use the special tool (scraper).Remove all carbon dust. Do not use CLP on the col-lar, gas block, or body.

    Clean the gas vent hole. See figure 2-35.

    Figure 2-33. Reticle Aiming Point and the Target Aiming Point.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-33

    Clean the central hole with the appropriate part ofthe scraper by turning it clockwise and pushing itinward toward the bottom of the housing. See fig-ure 2-36.

    Use the protruding tips of the scraper to clean thetwo grooves of the body. See figure 2-37.

    (3) Gas cylinder and piston. Use the special tool(scraper). Do not use CLP on the gas cylinder or piston.

    Clean the front interior of the gas cylinder (reposi-tioned in receiver with bipod in place) by insertingand turning the flat side of the scraper in a 360degree circular motion. See figure 2-38.

    Clean the internal grooves of the front side of thegas cylinder the same as described in the precedingbullet, except insert the scraper farther into the gascylinder. See figure 2-38.

    Clean the three grooves of the piston using a 360degree circular motion (see figure 2-39). Removeall carbon dust from the piston inside and out.

    Clean the hole in the front of the piston by insertingand turning the flat side of the scraper in a 360degree circular motion. See figure 2-40.

    (4) All other parts. Clean carbon and dirt from allother parts of the weapon.

    NOTEA cloth saturated in CLP is used on exteriorsurfaces to prevent corrosion.

    b. Lubricating. The lubricants authorized for fielduse on the SAW are CLP and LAW. They are used tolubricate certain parts of the weapon before, during,and after firing (see paragraph 2601). Each type is

    Figure 2-34. SAW Tool Storage.

    Figure 2-35. Cleaning the Gas Vent Hole. Figure 2-36. Cleaning the Central Hole.

  • 2-34 ___________________________________________________________________________________________________ MCWP 3-15.1

    best used in specific climatic and environmental con-ditions (see paragraph 2602).

    After the SAW is cleaned and wiped dry, a thin coatof CLP is applied by rubbing it with a cloth. Thislubricates and preserves the exposed metal parts dur-ing all normal temperature ranges. The moving partsare lubricated with CLP. After lubricating, rub thecomponents by hand to spread the CLP.

    (1) Operating rod group. Use CLP on the operating rodand spring, the slide assembly, the feed roller, and thebolt-locking lug.

    (2) Barrel group. Use CLP on the cam surfaces ofthe bolt-locking lugs, the heat shield, and along theouter surfaces of the barrel clamp.

    (3) Receiver group. Use CLP on all moving parts onthe cover assembly and the receiver rails.

    Figure 2-37. Cleaning the Grooves of the Body.

    Figure 2-38. Cleaning the Front Interior and Internal Grooves of the Gas Cylinder.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-35

    2603. Special Maintenance Procedures

    a. Climatic Conditions(1) Cold climates. In cold climates, the SAW mustbe kept free of excess lubricants, cleaners, and mois-ture, all of which can freeze and cause the weapon tooperate sluggishly. If brought indoors, allow the SAWto come to room temperature, wipe completely dry,and lubricate with a light coat of CLP. In temperaturesbetween 10 degrees Fahrenheit (-12 degrees centi-grade) and -10 degrees Fahrenheit (-23 degrees centi-grade), the SAW should be lubricated with CLP, orLAW. In sustained temperatures below -10 degreesFahrenheit (-23 degrees centigrade) use LAW only.

    (2) Hot, humid climates. In hot, humid climates,inspect more frequently for rust and keep free ofmoisture. Ensure that the SAW is lubricated properlywith CLP. Generally a heavier application of lubricantis required.

    (3) Hot, dry climates. In hot, dry climates, sand anddust must be kept from collecting in working parts.Clean the weapon daily with CLP. Wipe dry. TheTeflon coating left by the CLP will be sufficient tokeep the parts working smoothly.

    b. Nuclear, Biological, and Chemical (NBC)Conditions. If contamination is anticipated, applylubricant to all outer surfaces of the weapon (do notlubricate ammunition). Keep the weapon covered asmuch as possible. If the weapon is contaminated,decontaminate by following the procedures out-lined in FM 3-5, NBC Decontamination, then cleanand lubricate.

    2604. Inspection

    Inspection begins with the weapon disassembled inits major groups. Shiny surfaces do not mean theparts are unserviceable. The following parts of theweapon and related equipment are inspected forthe conditions indicated. Any broken or missingparts should be repaired or replaced according toTM 9-1005-201-10.

    Figure 2-39. Cleaning the Grooves of the Piston.

    Figure 2-40. Cleaning the Hole in the Front of the Piston.

  • 2-36 ___________________________________________________________________________________________________ MCWP 3-15.1

    a. Operating Rod Group

    The operating rod should not be bent, broken, orcracked.

    The buffer spring should not have breaks. Lug pins should protrude equally on both sides of

    the buffer spacer. The operating rod spring should not have kinks or

    separated strands or broken strands. It can have amaximum of one break on any one strand.

    The bolt assembly is checked for visible damage.The cartridge extractor should not be cracked orchipped.

    The slide assembly is checked for visible damage.The feed roller is checked for spring tension whencompressed and that the pivot slide is locked ontothe slide assembly.

    The firing pin is checked for straightness andcracks and that the tip is completely rounded.

    The firing pin spring should not be crushed or bent.The beveled end should not be stretched.

    The sear notch on the piston assembly is checkedfor signs of excessive wear or burring. Slight rota-tion of the piston on its housing is normal and is notcause for rejection.

    b. Barrel Group

    The flash suppressor should not be cracked, and itshould be fastened securely.

    The front sight post and front sight base must notbe bent, cracked, or broken.

    Weapons already zeroed should not be adjusted. The heat shield assembly is inspected for damage,

    cracks, or broken retaining clamps. The gas regulator and collar are checked for cracks

    or burrs. The barrel is checked for bulges, cracks, bends,

    obstructions, or pits in the chamber or bore. The gas plug is checked for obstructions, cracks,

    and bulges.

    The carrying handle is checked to ensure it is notcracked, broken, or missing; that it can be foldedunder spring pressure to the right and left; and thatit remains locked in an upright position.

    c. Handguard Group

    The handguard should not be cracked or broken. The retaining clip must be attached to the hand-

    guard retaining pin.

    d. Buttstock and Buffer Assembly Group

    The buttstock is checked for cracks, bends, orbreaks; and for missing components. It is checkedfor linkage and tension on the buffer rod.

    The shoulder rest is checked to ensure it is not bentor broken and that it locks in both positions.

    e. Trigger Mechanism Group

    The shoulder of the sear should not show exces-sive wear.

    The safety should function properly. (The searshould move only slightly when the safety is onSAFE, and freely when the safety is on FIRE).

    The sear pin should not protrude from the triggermechanism, because the trigger mechanism will notgo back in place.

    f. Gas Cylinder Group. The gas cylinder shouldnot be cracked, bent, or broken.

    g. Bipod Group

    The bipod group should not be cracked, bent, orbroken.

    The bipod legs should extend and collapse easily.

    h. Receiver Group

    The cover latch should work properly.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-37

    All parts inside the cover assembly should moveunder spring tension.

    All spot welds are checked for cracks. The cover assembly should remain open without

    support. The belt-holding pawl must be under spring

    tension. The receiver should not be bent or cracked. The cocking handle should slide freely within its

    guide and lock in its forward position. The windage and elevation knobs on the rear sight

    should be movable and legible. The windage scale screws should not be worn or

    burred.

    Section 7Ammunition

    This section covers the several different types of5.56mm standard military ammunition used in theSAW (see figure 2-41). Marines should becomefamiliar with and recognize the appropriate ammuni-tion types.

    2701. Classification

    Ammunition for the SAW is classified as listed:

    a. Ball. Used against targets of light material, per-sonnel, and during marksmanship training.

    b. Tracer. Used for observation of fire, signalling,and marking targets.

    c. Blank. Used during training when simulated fireis desired.

    d. Dummy. Used during training such as gun drill,and loading and unloading practice.

    2702. IdentificationThe type, caliber, model, and ammunition lot num-ber, including the symbol of the manufacturer, arenecessary for the complete identification of smallarms ammunition. The standard 5.56mm NATO car-tridge is completely identifiable by its appearance,the painting of the bullet tip, the manufacturers ini-tial and year of manufacture on the base of the car-tr idge case, and the markings on the packingcontainers. When removed from the original pack-ing container, the cartridge may be identified by itsphysical characteristics. The cartridge descriptionand characteristics are as follows.

    a. Cartridge, 5.56mm Ball M855 (DODAC 1305-A059). The M855 cartridge has a gilding, metal-jack-eted, lead alloy core bullet with a steel penetrator. Theprimer and case are waterproof. The ammunition islinked by a disintegrating metallic split-linked belt forfiring from the ammunition box (see figure 2-42). Inan emergency, the M855 round can also be loaded andfired from the SAW using a 20 or 30 round magazinefrom an M16. The M855 round is identified by agreen tip, has a projectile weight of 62 grains, and is2.3 cm long. This is the NATO standard round. It iseffective against personnel and light materials.

    b. Cartridge, 5.56mm Tracer, M856 (DODAC1305-A064). This cartridge has a 63.7 grain bulletwithout a steel penetrator. It is identified by an orangetip. The tracer is used for adjustments after observa-tion, incendiary effects, and signalling. When tracerrounds are fired, they are mixed with ball ammuni-tion in a ratio of four ball rounds to one tracer round.The DODAC for ball and tracer mix is A064.

    c. Cartridge, 5.56mm Dummy M199 (DODAC1305-A060). This cartridge can be identified by thesix grooves along the side of the case beginningabout one-half inch from its head. It contains no pro-pellant or primer. The primer well is open to preventdamage to the firing pin. The dummy round is usedduring mechanical training, dry-fire exercises, andfunction checks.

  • 2-38 ___________________________________________________________________________________________________ MCWP 3-15.1

    NOTE

    The older issue M193 (ball) and M196 (tracer)5.56mm cartridges can be fired with the SAW,but accuracy is degraded; therefore, it shouldonly be used in emergency situations when thenew M855 or M856 ammunition described onpage 2-33 is not available.

    d. Cartridge, 5.56mm blank M200 (M2 link,DODAC 1305-A075). The blank cartridge has noprojectile. The case mouth is closed with a seven-petal rosette crimp and has a violet tip. The originalM200 blank cartridge had a white tip. Field use ofthis cartridge resulted in residue buildup, whichcaused malfunctions. Only the violet-tipped M200cartridge should be used. The blank round is usedduring training when simulated live fire is desired.

    Figure 2-41. Cartridges for the SAW.

    Figure 2-42. Cartridges in Metallic Belt.

  • Machine Guns and Machine Gun Gunnery ___________________________________________________________________ 2-39

    An M15A2 blank-firing attachment must be used tofire this ammunition.

    2703. Ballistic Data

    Figure 2-43 shows some examples of the penetrationcapability and other ballistic data for the M8555.56mm ball round when fired from the SAW.

    2704. Ammunition Packaging

    The ammunition can contains two plastic ammunitionboxes. Each box contains 200 rounds and weighs 6.92

    pounds. Dummy ammunition (M199) is packed inboxes of 20 rounds each.

    2705. Storage

    Store ammunition of all classes away form heatsources such as; open f