Colt Revolvers Workshop Manual Vol 1 - Jerry Kuhnhausen.pdf

Acknowledgements

A special thanks to the following manufacturers who were generous enough to contribute items of reader

interest, including: photographs, artwork, illustrations, phantom illustrations, cross-sectional drawings,

parts diagrams, exploded diagrams, and technical data.

Colt Industries Inc., Firearms Division

Ransom International Corp. Clymer Manufacturing Co., Inc.

Gun Parts Corporation

Millett Sights

Colt has not published shop manuals on the mechanics of their revolvers, possibly on the belief that shelf

availability of mechanical information might allow the untrained and/or unqualified to "fix", or otherwise

tinker with, Colt firearms which were not in need of repair in the first place. But, with or without books

on the subject, (and the cautions and safety warnings contained therein) tinkerers, being irrepressible, will

tinker, just the same. In the absence of specific model training programs, we believe professional

armourers, gunsmiths, and revolversmiths will be better served by the data in this shop manual than by no data at all- and they might be helped even more by the safety warnings, cautions, and maximum-

minimum specifications given. As we see it, it's also only fair that non-professionals have ready access to,

and benefit of, as many of the very same cautions, safety warnings, and specifications as possible. In this

way, perhaps a caution might be read and heeded before the fact of an unsafe act, mishap, injury, etc.

Hopefully, the very complexity of this subject might convince the nonprofessional to take his revolver to

a Colt qualified revolversmith for repair, if, or when, repair is needed.

These days, U.S. manufacturers are under a heavy liability load. The problem is even greater for

manufacturers with independent field repair networks. That field repair stations exist to offer regional

customer service provides the manufacturer no relief.

With factory liability in mind, the following disclaimer is included at Colt's request:

"The content of this book reflects the writer's experience and is not necessarily the recommendation of

Colt. Colt, therefore, shall not be liable for the content of this book nor for any mishap claimed to result

from the use of this published material. Colt instructions for users are contained solely in its manuals,

which are available free from its factory, (P.O. Box 1868, Hartford, Connecticut 06102)."

The Colt logo, Rampant Colt, Serpentine Colt, and Rampant Colt in a circle, used in this publication to

identify Colt products, are registered trademarks of Colt Industries, Inc.

4 Contents, Section I Page

Introduction ........................................................................................................................................... 6

About Colt's D, E, & I Frame Revolvers ................................................................................................. 7

Historical ............................................................................................................................................... 8

Early Model ..........................................................................................................................................13

Intermediate & Late Models ..................................................................................................................16

About Gunsmithing the Colt D.A. Revolver ..........................................................................................17 D, E, and I Action Safety Features .........................................................................................................19

Gunsmith's Safety Rules........................................................................................................................20

Disassembly Pre-checks ........................................................................................................................21

Disassembly .........................................................................................................................................22

Pre-check Safety Assembly ...................................................................................................................33

Early and Late Style Crane/Cylinder Assemblies ...................................................................................38

Detail Cleaning Before Inspection .........................................................................................................43

Frame and Barrel Inspection ..................................................................................................................46

Damaged Frames ..................................................................................................................................47

Damaged Forcing Cones .......................................................................................................................50

Damaged Barrels ..................................................................................................................................51 Begin Parts Checkout & Reassembly .....................................................................................................52

Critical Parts .........................................................................................................................................54

About Early & Late Cranes ...................................................................................................................55

Check Early Style Crane/Frame Fit .......................................................................................................57

Check Late Style Crane/Frame Fit .........................................................................................................59

Check Crane Alignment ........................................................................................................................60

About Cylinder Service Procedures .......................................................................................................61

Cylinder Checks ...................................................................................................................................62

Check Early & Late Ejector/Ratchets ....................................................................................................63

Early & Late Ejector Rods ....................................................................................................................65

Cylinder Reassembly ............................................................................................................................67

About Headspace, Endplay, & Barrel Clearance ....................................................................................70 Headspace and Clearance Table ............................................................................................................71

Three-Way Headspace/Endplay/Gap Relationship .................................................................................73

Gauge Check Headspace .......................................................................................................................74

Cylinder Bolt Inspection and Fitting ......................................................................................................76

D, E, and I Triggers...............................................................................................................................82

Safe Trigger Pull ...................................................................................................................................84

Hammer Push-Off .................................................................................................................................85

Safety Assemblies, Early and Late.........................................................................................................87

D, E, and I Hammers .............................................................................................................................90

Firing Pins and Firing Pin Problems ......................................................................................................91

Firing Pin Protrusion .............................................................................................................................93 Check D.A. Hammer Strut ....................................................................................................................94

Hammer-Trigger Pre-check ...................................................................................................................96

About D, E, and I Hands .......................................................................................................................97

About Rebound Levers ....................................................................................................................... 102

High Rebound Cam............................................................................................................................. 103

Low Rebound Cam ............................................................................................................................. 106

Rebound/Hammer Problems................................................................................................................ 107

Other Rebound Related Problems ........................................................................................................ 108

5 Before Timing Bolt Drop .................................................................................................................... 109

About Bolt Drop Timing ..................................................................................................................... 110

Before Top & Bottom Hand Fitting ..................................................................................................... 111

Top & Bottom Hand Checks & Fitting ................................................................................................ 113

Stretch Short D and E/I Hands ............................................................................................................. 117

About Ratchet Lug Fitting ................................................................................................................... 118

Bottom Hand & Ratchet Seating.......................................................................................................... 119

Hand/Shell Head Clearance ................................................................................................................. 120 Mainsprings & Trigger Pull ................................................................................................................. 121

Test S.A. & D.A. Trigger Pull ............................................................................................................. 123

Safety and Common Sense .................................................................................................................. 126

Troubleshooting Guide........................................................................................................................ 129

Factory Lubrication Specifications ...................................................................................................... 137

Contents, Section II, Shopwork ......................................................................................................Page

Sights and Sight Work ........................................................................................................................ 140

Replace Trigger/Hammer Frame Pins .................................................................................................. 146

Replace Recoil Plate ........................................................................................................................... 148

Align/Straighten Crane, Old Method ................................................................................................... 149

Align/Straighten Crane, New Method .................................................................................................. 150 Misfit Cylinder Bolts .......................................................................................................................... 152

Replace Cylinder Bolt ......................................................................................................................... 153

Replace Trigger .................................................................................................................................. 154

Basic Sear Fitting Angles/Trigger Pull................................................................................................. 155

Replace Hammer Assembly ................................................................................................................ 156

Replace Cylinder Hand ....................................................................................................................... 157

New E/I Hand Fitting Points ............................................................................................................... 158

New D Hand Fitting Points ................................................................................................................. 159

Fitting New or "Unequal" Ratchet Lugs ............................................................................................... 160

Misfit Rebounds & Why Rebounds are Replaced................................................................................. 161

New E/I Rebound Fitting Steps ........................................................................................................... 162

New D Rebound Fitting Steps ............................................................................................................. 163 More on Fitting New Rebound Levers ................................................................................................. 164

Why Cylinder Collars are Stretched..................................................................................................... 166

Why Cylinder/Ratchet Assemblies are Replaced .................................................................................. 168

About Early D & E Cylinders .............................................................................................................. 169

Set Cylinder Headspace ...................................................................................................................... 171

Set Ratchet Length (Set Endplay) ........................................................................................................ 172

Ratchet/Hand Clearance ...................................................................................................................... 173

Why Barrels are Replaced ................................................................................................................... 174

Remove Barrel .................................................................................................................................... 175

Barrel Requalification or Set-Back ...................................................................................................... 176

Final Check Barrel Fit & Torque Barrel ............................................................................................... 178 About D, E, and I Model Forcing Cones .............................................................................................. 179

Cut and Gauge Forcing Cone .............................................................................................................. 180

Recut Barrel Crown ............................................................................................................................ 182

Plug Gauge/Range Rod Check ............................................................................................................ 183

Tuning Factors in Match Actions......................................................................................................... 184

Drag Elimination in Match Actions ..................................................................................................... 186

Test Firing 6x6 for Match Accuracy .................................................................................................... 188

Parts Diagrams.................................................................................................................................... 190

Factory Discontinued Parts Section ..................................................................................................... 202

6 INTRODUCTION

This book was reprinted from a series of highly detailed, loose-leaf gunsmith training manuals written by

gunsmith Jerry Kuhnhausen for the original purpose of training and shop use by his personnel. See about

author, inside rear cover.

The Colt Double Action Revolver- A Shop Manual, Volume I, is one of several VSP shop manuals

written by Jerry Kuhnhausen on Colt's revolvers, and the first of the Colt revolver series to be released. Volume I covers D, E and I frame revolvers in great detail. With their inherent design similarity, models

built on these frames group quite naturally. The later Mark III, Mark V and AA model revolvers are of an

entirely different design and form their own separate group, discussed in Volume II. Colt's much older

single action revolvers form yet another grouping, and are the subject of another manual.

For reader convenience, the printer has resized this manual to standard book size, retaining the author's

original photographs, illustrations, and instructions. Additional supplemental artwork, drawings, and data

have been supplied by courtesy of Colt Industries, Firearms Division.

Due to the similarity between Colt's D, E, and I frame revolvers, Volume I combines them, and covers the

majority of the many models built on these frames. However, the author strongly points out that, even though the smaller D frame models can be considered similar to the larger frame E and I models in many

respects, they are not the same. The text clearly details the differences.

Although, for the most part, Kuhnhausen's manuals were originally assembled with shop training in mind,

they soon became exceptionally valuable as easy gunsmithing references when questions came up at the

bench, as they inevitably do. These informative shop manuals are presented in a step by step sequence,

just as you would normally go through fitting or refitting work at the bench.

The Colt Double Action Revolver. A Shop Manual. Volume I- is a practical repair manual, and a package

of ready information. The first section covers disassembly, inspection, basic checks, parts identification,

and interior servicing. It then goes on with reassembly, fitting and refitting details, further parts checks,

and basic repairs. A troubleshooting guide is included. D, E, and I model differences are discussed and illustrated throughout. Safety and common sense are continually stressed.

The heavily detailed second section contains the most often requested shop work, and discusses the fine

points of advanced bench and shop gunsmithing techniques. In this section, the author devotes more

attention to the details of frame, barrel, crane, and cylinder work. Forcing cone work, and the tools

needed to do it, is covered as well. Parts diagrams for current, intermediate, and older models are included

at the back of the manual.

This manual covers nearly everything the gunsmith or armourer needs to know about repairing and

refitting Colt's D, E, and I frame double action revolvers. It is the most complete gunsmithing work on

these models we have ever seen. -The Editors

7 About Colt's D, E, and I frame double action revolvers-

The events of history tell us that the swing-out cylinder double action revolver was a very difficult critter

to invent- that is, difficult for everybody other than the design department people at the Colt Firearms

Company.

A double action revolver with a cylinder that would swing out for loading and unloading was still a

science fiction writers' dream in the year 1876. At that time, inventors and arms firms in Europe were working largely on single action swing-out cylinder ideas. Only a few advanced arms designers were

toying with concepts that could actually lead to production swing-out cylinder double action revolvers.

But, most of those concepts involved cumbersome modifications of earlier single action revolvers.

Meanwhile in the U.S., Winchester was also experimenting with double action swing-out cylinder

designs. As it turned out, the sum of the efforts on both sides of the Atlantic amounted to very little. In the

language of today, I imagine the various projects ran out of their respective R&D budgets, and were

finally dropped, favouring other, better paying work.

This interesting situation left the entire job of inventing a marketable, swing-out cylinder, double action

revolver to the Colt Firearms Company. And that's exactly what they did.

The first Colt principle patents were issued sometime in December 1881.

The first prototype patent was assigned to Colt's Firearms Co., in August 1884.

Colt's first production double action, swing-out cylinder revolver was the Model of 1889. Colt designated

this revolver the Model 1889 Navy.

The 1892, 94, 95, 96, 1901, and 1903 models followed. Essentially, all of these revolvers were

improvements on the original Ml889. Even the rare USMC Model of 1905 was basically a Model 1889

Navy, with improvements.

These early Colt revolvers were the evolutional forerunners of the later medium size E frame revolvers

such as the Army Special, Official Police, Officer's Model Target, and Officer's Model Match. The very first of this series, the Army Special Model [introduced in 1908], standardized medium frame hand and

sideplate position on the left side of the frame. This standardized medium frame cylinder rotation in the

clockwise direction. Earlier models were opposite rotation. In turn, the original Trooper model, the .357

Magnum model, and finally the Python, evolved from the E, and were designated as I frame models.

Colt's smaller D frame revolvers also evolved directly from an ancestor called the New Pocket Model .32

of 1893. Interestingly enough, manufacturing changes in these revolvers had actually standardized

clockwise cylinder rotation in the small frames in 1903, well before standardization occurred in the

medium E type frames. Incidentally, the "D"-frame designation was not used by the factory until 1947.

No one I've talked to at Colt seems to remember just when the "E" model designation was assigned.

8 In 1905, the positive lock system was introduced across the existing Colt double action line. This addition

created the Pocket Positive .32, and the Police Positive in both .32 and .38 calibres. These revolvers were

followed by the Police Positive Special [.38 special, with 1 5/8" cylinder] in 1908, and later by the

Detective Special, Bankers' Special, Cobra [first aluminium D frame], Air Crewman, Courier, Agent, and

Border Patrol models. The last D frame variation was the Diamondback model, introduced in 1966. The

first medium frame incorporating the positive locking system was the Army Special, introduced in 1908.

Colt's superb large frame revolvers, although not included or mechanically discussed in this book, are mentioned because of their historic design similarity, shared features, and direct relationship to both the

small and medium frame models. They are, in fact, a chunk of the same development history. These large

frame double action revolvers originated with the New Service Model of 1898. By the end of production,

they had been manufactured in numerous model variations and chambered for 18 different cartridges.

New Service revolvers manufactured after 1905 and the introduction of the positive lock system are

referred to as "new" or "improved" models. Best known New Service Model variations are the Ml909

Army, Navy, and USMC models, the Shooting Master, and the M1917 U.S. Army model, in .45 ACP.

Production ended in 1944. Colt has not produced a large frame double action revolver since that date. The

absence of this model is truly a pity, particularly since the .45 Colt cartridge has been re-discovered by a

new generation of sport shooters and by law enforcement agencies, as well.

A chronology of Colt D.A. revolvers and improvements:

1877 -Colt Lightning Model, Colt's first double action

1878 -Colt D.A. Frontier Model 1881 -D.A. swing-out cylinder patents 1884 -Prototype model patented

1889 -New D.A. Navy Model

1892 -D.A. cylinder bolt slots added

1892 1894, 1895, 1896, 1901, 1903 Army and Navy Model updates

1893 -New Pocket Model .32 1896 -New Police Model .32

1898 -New Service Model/Shooting Master

1903 -New Pocket Model, cylinder revolution clockwise

1904 -Officer's Model 1905 -USMC Model [Updated variation of 1889 Navy] 1905 -Introduction of positive lock system

1905 -Improved New Service Model

1905 -Pocket Positive Model

1905 -Police Positive .32 and .38

1908 -Clockwise rotation standardized, medium frames

1908 -Army Special

1908 -Police Positive Special [.38 Spl., 1 5/8" cylinder]

1909 -Large frame Ml909 Army, Navy, USMC models

1910 -Police Positive .22 Target

9 1917 -Large frame M1917 U.S. Army, .45 ACP

1921 -Camp Perry Model

1927 -Official Police Model

1927 -Detective Special Model

1928 -Banker's Special Model 1930 -Official Police .22 Model 1930 -Officer's Model Target 1933 -

Pequano Model

1942 -Commando Model [WW II]

1949 -Officer's Model Special Target 1950 -Cobra L.W. aluminium frame

1951 -Aircrewman [experimental series]

1952 -Officer's Model Match

1952 -Border Patrol Model

1953 -Courier Model

1953 -.357 Magnum Model

1954 -Marshall Model

1954 -Trooper [original model]

1955 -Python Model 1962 -Agent Model

1966 -Diamondback Model

1969 -Mark III [J frame series] introduced 1969 -Mark III Officer's Model Match

1977 -Viper Model

1984 -Mark V series introduced

1986 -King Cobra Model introduced

-Colt Python product photo courtesy Colt Industries, Firearms Division

The Colt logo is a registered trademark of Colt Firearms

The Colt DA Revolvers, Section I 10

Ammunition Chart for Colt Arms

Figure A- Historical ammunition listing reprinted from an early Colt catalogue, circa 1930. Standard

chamberings for many of the early Colt models are listed. Other calibres/chamberings were available on a

special order basis. The majority of the above models and chamberings are now factory discontinued.

-Photo courtesy Colt Industries, Firearms Division


How Colt Fire Arms are Made Every bar of steel used in Colt Fire Arms manufacture is compounded and rolled at the Steel Mills in accord with Colt specifications. Materials are not only carefully selected but are subjected to the most

scientific analyses and tests by trained engineers and heat treated by expert

metal hardeners. Parts are micrometer gauged for absolute accuracy, finishing

operations carefully checked and assembly of arms accomplished by expert

workmen. Finally, each arm is adjusted, proof tested, and shot or targeted by

experienced marksmen to determine accuracy and exactness of operation,

before it is put through the final inspection and is entitled to have stamped

upon it the little triangular "Verified Proof" mark.

A brief description of some of the thousand operations necessary to produce a Colt Revolver or

Automatic Pistol will suffice to show what infinite care and skill is given to every step in their manufacture. From a forge a workman draws a bar of glowing steel. Under a thudding drop forging

hammer it goes. The die descends with a force of several tons and the frame of a

revolver or automatic pistol is roughly shaped. Blow after blow it receives, each

fixing more firmly the fibres of the steel. Deftly the metal is turned over and over as

the descending die beats the tough steel into an unbreakable mass. Similarly, but of

different steels, each selected for its peculiar properties of toughness or hardness,

are forged the hammer, trigger, crane and other parts.

In another department a skilled mechanic operates a machine which cuts the

blanks from which revolver cylinders are made. This same automatic machine,

which operates with uncanny dexterity, trues up the outer surface of the blank and

bores the center hole; the chambers are then machine-reamed, grooved and counter-bored for ratchet and coupling and then the final operation of hand reaming

is performed.

To follow the progress of a revolver barrel through its many delicate operations from one skilled workman to another is to repeat the experience of the cylinder. In

rifling the barrel, a feature of vast importance, Colt's acknowledge no equal. By an

ingenious method the rifling of the barrel is spiralled in a direction opposite to the

thread that fastens it to the frame so that a bullet passing through the barrel tends to

keep the barrel tight in the frame.

-Courtesy Colt Firearms


The Colt One-Piece Frame which constitutes practically the entire bulk of the Arm,

is forged from one solid piece of steel into the forward end of which the barrel is

permanently fastened by means of a tapered thread. There are no joints or hinges to

impair its strength or disturb the permanent alignment of cylinder chambers with

barrel. This construction insures absolute rigidity and unusual durability.

All Colt Revolver cylinders turn right. This feature alone marks the Colt as the

greatest achievement in revolver manufacture. Years ago Colt's discarded the left

revolving cylinder as impractical because of liability to force the cylinder chamber out of line with the barrel causing a certain amount of the bullet to be sheared off by the barrel. No Arm can possibly be

accurate unless the chamber and barrel are in perfect line. Right turning holds the crane tightly against the

frame — the cylinder chamber and barrel always in absolute line for every shot.

THE COLT POSITIVE LOCK

The Colt Positive Lock operates automatically between the frame and the face of the hammer in all Colt

double-action revolvers. It requires no manipulation by the operator, hence the

expression: "You can't forget to make a Colt Safe." When the trigger is drawn back

as the hammer is cocked or drawn to a rearward position the positive lock or safety

is drawn downward permitting the full blow of the hammer to fall directly upon the

primer of the cartridge if the trigger is held in this position. At all other times the Positive Lock prevents the hammer nose from coming into contact with the primer.

Figure B- Early two page Colt advertisement discusses the, by-now obvious, quality of Colt's double

action revolvers. The above reference to the "Colt one- piece revolver frame" [plus sideplate] points out

the difference in strength between solid frame revolvers and hinged break top types. Colt's aim was to

supply the best, and make sure the customer knew the difference.




Figure E- Illustration shows intermediate and late Colt D, E, and I model revolvers. The original Trooper

model, shown, is an I frame. Later Mark III Troopers were built on J and V frames. -Courtesy Colt Firearms, Colt logo is a trademark of Colt Firearms


Colt's Police Python

Model 1-3 specifications Calibre Barrel

Lgth.

Over- all

Lgth.

Wgt. (Ozs.) Sights Trigger Hammer Spur Stock Finish

.357 Mag 2·5" 7·5" 39 Adjustable rear sight.

Ramp-type front sight,

Grooved Fast-cocking wide-spur,

checkered

Checkered walnut, square butt,

target stocks, "gold" medallion.

Service stocks on 2·5"

Colt

Royal

Blue Nickel

plate

optional

at additional

cost.

4" 9·25" 41 6" 11·25" 44

BALLISTICS PERFORMANCE

CARTRIDGE BULLET VELOCITY- FEET PER

SECOND

ENERGY- FOOT

POUNDS

MID-RANGE

TRAJECTORY

TEST BARREL

LGTH.

Wgt. Grs.

Style Muzzle 50 Yds. 100 Yds. Muzzle 50 Yds.

100 Yds.

50 Yds. 100 Yds.

158 Soft Point 1550 1380 123C 845 665 530 0.5" 2.5" 8·375

158* Metal

Point 1410 1240 1120 695 540 440 0.6" 2.8" 8·375"

158 Lead 1410 1240 1120 695 540 440 0.6" 2.8" 8·375"

Figure F- An early Colt Police Python specification sheet. This model, now simply called the Python, is

the only I frame model in production at this time. In my estimation, the Colt Python stands as the ultimate

double action revolver design. -Courtesy Colt Firearms


About gunsmithing the Colt double action revolver-

Before 1950, virtually every revolversmith was familiar with the fine points of operation, repair, and

action timing of Colt's double action revolvers. In those days, a revolversmith who didn't know his Colts

was thought not to know very much about anything. Not that much repair work was needed. Colt

revolvers left the factory then, as now, well fit and finished, detail inspected, and stamped by both the

builder and final inspector. Reputations were on the line.

Revolversmiths and general gunsmiths alike owned Colts, and couldn't help but be familiar with them.

From the beginning, revolversmiths were fascinated by the excellent design, high quality steel, and

incredibly well made parts. Colts were brought in for re-bluing, custom trigger and sight work, or for an

occasional lost part, jiggered screw, broken spring, or new holster. Owners survived by and swore by Colt

revolvers, and knew that you couldn't really wear one out. You'd have to throw your revolver in the creek

to damage it- and nobody in his right mind would do that.

Probably this overall familiarity with Colt's revolvers had as much to do with their long and successful

history [starting with the Patterson Model of 1836] as did their superb product quality and reliability. All

this had been going on for so long that, by WW II, this knowledge had become even more than just a tradition, it was the way things were: it was reality.

But the emergence of WW II changed this aspect of history, as it did everything else. And, of necessity,

military contracts preoccupied the factory through the M-16/AR-15 era, causing Colt's market

aggressiveness in both the civilian, and law enforcement market areas to wane. This left the majority of

such sales to other companies and products.

By the mid-1980's, revolver smithing traffic had largely vested in other brands and models. The old Colt

revolver familiarity was almost gone. Forty years had passed since the end of WW II. Retiring armourers,

gunsmiths, and law enforcement people had taken most of their practical Colt knowledge with them.

By now, Colt's D, E, and I model double action revolvers seem complicated to many otherwise fully competent gunsmiths. Some even hold Colt's D.A. revolver actions, and particularly the Python action, in

a sort of mechanical awe, thinking of them as unfathomable "Swiss watch" mechanisms.

Other than a single brief pamphlet intended primarily for law enforcement armourers, the factory has

never put out a service manual on their double actions, or on any of their revolvers, for that matter. Early

on, since just about everybody seemed to know how they worked, manuals didn't seem necessary.

In actuality, Colt D, E and I frame actions are basically straightforward and simple. They may seem

complicated at first, but are very quickly learned by closely observing the basic interaction of the parts;

such as cylinder bolt and rebound lever, trigger and safety linkage, hand and ratchet, etc. In fact,

observing both correct and incorrect bolt and rebound function in a cutaway revolver is the best way to familiarize yourself with this pivotal action function.


The real value of cut-away revolvers in all aspects of revolver

smithing, action work and training is never more evident than on the

subject of D, E and I model revolver rebound lever fitting and bolt

timing. A cutaway revolver can visually and simply explain all action, and action timing, problems. Nearly every parts interaction can be

fully demonstrated. For example, a cut-off rebound lever can easily

demonstrate "hammer on" and "hammer off" the rebound lever- and

related fitting requirements, at a glance.


Figure S1- Action safety features are shown in a late model stainless steel Python. The inset illustration-

courtesy Colt Firearms, shows the positive lock safety system used by Colt since 1905. This basic design,

used throughout D, E, and I production, has been updated to accommodate later style hammers.

A. The trigger actuated upper safety [or safety hammer block] stays in place between the hammer

and frame, until physically lowered by:

1. Cocking the hammer in single action

2. Squeezing the trigger in double action mode After firing the revolver, or indexing the action, the returning trigger, by way of the connected safety

lever, returns the upper safety to its positive hammer block position.

B. The rebound lever cycles [or rebounds] the hammer back after firing, and:

1. Withdraws the hammer and firing pin to a safe rear position behind the frame [or recoil plate in

D and E models]

2. Returns the trigger and cycles the safety lever and upper safety [hammer block] into the positive

lock position between frame and hammer

C. The bottom arm of the mainspring is also a part of the safety system in that it supplies rebound

lever spring pressure, which in turn:

1. Rebounds the hammer, withdrawing the firing pin 2. Returns the trigger and hand

3. The trigger, in turn, cycles the safety lever and the upper safety back to the positive lock,

blocked hammer position

To be doubly safe in the field, load one round less than a full cylinder, and then make 100% sure the empty chamber is under the hammer. This conservative habit dates back to frontier single action days- and helps demonstrate that the best safety feature is a careful owner. This is true, without exception, even though no firearm of any style or brand has been known to point or function on its own. It's a simple matter of cause and effect. Somebody has to do the

causing...


REALLY NOW, WERE YOU GOING TO SKIP THIS PAGE?

A Gunsmith's Safety Rules- Or How To Stay Out Of Trouble, And Out Of Court, At The Same Time.

1. NEVER alter, or remove, any safety feature from any gun, EVER. If the owner

insists, let him do it, then it's strictly his liability- and not yours.

2. DON'T work on any gun with a safety part removed, unless the work includes

correct reinstallation of the safety.

3. FOR your protection, always keep records of work done.

4. IF you begin work on a gun that you determine is not reliably repairable (or even

just inspect a gun not in good working order) even if it's for a best friend (or for

free) always write "WARNING- NOT SAFE TO FIRE" on the shop ticket.

5. DON'T do patch-job repairs. Do it right, or skip it.

6. DON'T work for people who insist on substandard work. These are the ones who

will want it redone later (and for nothing) and will probably sue you for any

mishap.

7. NEVER trust anybody, THAT GUN IS ALWAYS LOADED!

8. NEVER hand, or take, a gun- unless you have personally checked its

chamber(s).

9. NEVER point any gun, except at a target.

10. NEVER believe what someone says about the condition of any gun, until you

have fully inspected it yourself.

11. NO dry firing without spent shells, or snap caps, no matter WHO says it's O.K!

12. NEVER forget to check for barrel obstructions or bulges. Just do it- it's only

common sense.

13. FOLLOW these safety rules, after all, the life you save may be your own.

14. THINK it through first, it always saves time later.

If you violate these simple rules, you will, sooner or later, pay the price for it.


BEFORE DISASSEMBLY

Don't disassemble a revolver brought in for servicing or repair before you have gained an overall idea of

what could be right or wrong with it, and what work might be needed. Experienced armourers and

gunsmiths always take the necessary few minutes to pre-check a revolver, generally following a list much

like the one below. Before the sideplate is removed, a detailed pre-check sequence helps them focus on

the action area, or part, that may be causing a problem. Usually, a few minutes taken in the beginning will save a lot of time later.

Also, something else to watch for is the little chip, broken-off corner, or piece of hard grit that has lodged

somewhere inside and is creating problems. In a hurry, you might drop out a small particle such as this as

you remove the sideplate, missing where it came from, and as well, any possible damage that it may have

caused. In some cases, these small particles have been found to be sharp fragments or corners broken off

sears or hammer engagement ledges. Of course, the broken part must be replaced. Any damage caused by

contact with the fragment should be found and corrected. For these reasons, it's not a bad idea to take a

few minutes to read through the following pre-check list:

Before Disassembly Pre-Check List:

1. Move cylinder latch- sticky? open- close OK?

2. Check cylinder- open and close OK? rough? smooth?

3. Spin cylinder- sticky? OK? is the ejector rod straight?

4. Twist ejector rod or rod head- loose? OK?

5. Push ejector rod- smooth? drag? returns OK?

6. Examine ejector star, pins, and ratchet- sideplay on pins? OK?

7. Check cylinder front- barrel hits? nicks? other? OK?

8. Check cylinder fit- endplay OK? is bolt lock-up OK?

9. Check bolt- instant pick-up? is drop on time?

10. With cylinder open, check feel of single and double action- OK?

11. Close cylinder, repeat S.A. & D.A. check- stiffer? or about the same? 12. Slow and fast D.A. check- does cylinder bolt lock before hammer falls?

13. Feel mainspring- seem weak? OK? any hand/cylinder bind? OK?

14. Check hammer push-off, from rear and both sides- OK?

15. Check trigger pull- as specified for model?

16. Visual internal safety check- is it installed? drags? OK?

17. Check barrel fit in frame- loose? tight? at 12:00 O'clock?

18. Inspect forcing cone, hand, recoil plate, and firing pin extension- OK?

19. Inspect bore- obstructed? bulged? scored? visible wear? rust? OK?

20. Inspect muzzle crown- nicked? dented? recut? OK?

21. Check trigger, hammer- drag marks? firing pin bent? OK?

22. Note sideplate condition- removed before? played with? screws OK? 23. Check sights- modified? loose? are pins and adjusting screws OK?

24. Note general appearance- worn? scratched? dents? rusty? like new?

Likely as not, it will take you the better part of a half hour the first time you go through the above list

seriously, with a revolver in hand- but make it a habit, anyway. Make pre-checking second nature just like

it is with all good revolversmiths. Later on, you'll do it in minutes.


Figure 1- The illustration shows the cylinder open- and the

revolver's unloaded status being positively verified. This basic

step is always first in firearms handling and revolver smithing. Viewing a closed cylinder from the side is as unreliable as

taking someone's word that the revolver is unloaded. Never

rely on a side view.

Figure 2- Shows a Colt target style revolver grip. The stock

screw nut is located in the right panel. A stuck screw can twist

the nut loose inside the grip panel. A drop of penetrating oil

can help loosen stuck threads. Service and target style grip

screws are shown below. Pre- grind screwdriver blades to fit screw slots.

Begin Disassembly Always start with a clean bench. Get

rid of any sharp chips that may be left

over from earlier drilling, milling, or

filing. Carefully remove any polishing

grit or other surface damaging

material. Customers, and even friends, become rightfully irate when scratches

accompany repair work. That you

didn't charge for the scratches makes

very little difference. Best bench

covers for finish protection are:

reversed leather, felt, or 3/16" outdoor

carpet. All are equally useful, but only

to the extent that the working surface

is kept 100% clean. As you

disassemble, box all parts with their

original frames: otherwise, mated and specially fit action parts can be mixed

up, and screws, pins, and springs

misplaced.

Warning: Before starting work, or

moving the hammer or trigger, always

confirm unloaded status. Don't work

on it until daylight is visible through

all six chambers. The hazard created

by a crimped .32 revolver or .380 auto

round pushed part way down a

chamber is very real. If a cylinder like this was placed in a hot bluing tank,

the accident potential could be great.

A gunsmith can miss this kind of thing

by just not expecting to see it. Remove

Grip [Stock] Screw If not well ground

and fit, frozen grip screw threads can

cause a screwdriver blade to roll out,

damaging the slot. See figures 2 and 3.

Rusty threads may cause the stock

screw nut to spin inside the grip. Pre-

lubrication helps.

VISUALLY CHECK

CHAMBERS

CYCLE EJECTOR ROD

MAKE SURE YOU SEE

DAYLIGHT THROUGH ALL

CHAMBER POSITIONS

PULL BACK

CYLINDER

LATCH


Remove Grips

Colt grip screws have been made in

two styles: service type [small heads

with wide slots], and target type [large

heads with thin slots]. See figure 2.

Avoid both grip finish and screw slot damage by using correctly ground, full

slot fitting screwdrivers. Inexpensive

grinding fixtures are made for this

purpose. See figure 3.

1. Dress screwdriver blade edges

[width], as required to prevent

grip finish damage.

2. Then, while holding firm down

pressure, loosen the grip screw

and twist out. 3. When resistant, first pre- lube the

threads with a thin penetrating

oil, then rap the handle of the

screwdriver sharply before

rotating.

4. Don't attempt to pry grips off.

Once the grip screw is loose,

instead, push it back in with the

screwdriver tip. This pushes the

grip off the frame on the back

side, and without marking.

Remove the opposite grip from the inside.

Frozen Grip Screws

Sometimes, grip screws are frozen or

rusted to the extent that they spin the

stock nut inside the grip. If the grips

are to be salvaged, there is only one

workable remedy:

1. Carefully centre punch and drill

out the frozen screw threads. Prevent spin by holding and

backing up the screw head with a

Magnatip screwdriver bit

chucked in a drill press vice.

This method can save serviceable

grips.

2. After removing the screw,

push the opposite grip off with a 1/16"

punch.

Figure 3- Shows a screwdriver tip being hollow ground to correct slot fit on a bench grinder using an MMC blade fixture.

This excellent and handy fixture easily produces precision,

parallel faced blades and perfectly square tips. This is a

necessary pistol smithing step. Some screw slots won't give

you a second chance.

Figure 4- Shows the right grip being removed by correctly

pushing it off the frame with the grip screw. A frozen grip

screw can be drilled free of a spun stock nut. If overall

condition makes the stocks worth saving, a replacement stock

nut can be retained by cementing it in with Microbed or

Acraglas bedding compound.


Figure 5- Shows an early style crane lock screw and crane lock

detent. The two interlock and fit the frame with almost zero clearance. For this reason, dried oil varnish tends to glue the

lock detent in place, making the screw seem frozen. Inset

illustration shows correct hollow ground blade contact at the

bottom of the screw slot.

Figure 6- Shows an early style crane lock screw and crane lock

detent body, after removal. The detent extractor ring machined

into the screw [looks like a washer] withdraws the detent body

as the screw rotates out. Ring damage can bind the lock screw,

making twist out difficult. A few drops of oil around the screw head helps.

Remove Crane Lock Screw [Early

Style]

Early style crane lock detents are

easily identified by their side

positioned, interlocking detent screws.

See figure 6. This original locking

system was used by the factory for over 50 years. Colt replaced this

system with the much simpler present

design, as a first step in what became

the late style crane and cylinder

assembly update package. With the

older Colt double action models now

becoming even more collectible, extra

care in preserving finish is suggested.

For this reason, correct, hollow ground

screw drivers are an absolute must.

1. Adjust screwdriver blade grind to

bottom blade contact as

illustrated in figure 5. This helps

prevent flaring the screw slot

and/or chipping the edges of a

plated finish.

2. While holding firm down

pressure, rap the screwdriver

handle impact driver style, and

rotate the screw out.

3. If resistive, place a few drops of

penetrating oil on and around the screw, wait a few minutes, then

twist out.

4. In cases where either the lock

screw or lock detent [or both] are

stuck, don't attempt to force the

screw. Instead, use the screwjack

or drill press frozen screw

removal method as discussed in

detail in figures 9 and 10.

5. Always use a support and

levelling block similar to the one illustrated in figure 8. Whether

early or late model, the crane

lock screw is the single most

visible screw on the entire

revolver.


Remove Crane Lock Screw [Late

Style]

Late type crane lock screws are

counterbored, and have shallower

screw slots than the older style. For

this reason, screwdriver fit is just as important with late style lock screws:

though wider, there is less available

screwdriver slot depth. Although all

late D and E/I lock screw thread

diameters are the same, D model crane

lock screws run .015-.020" shorter,

and can, with lot variations, have

smaller blade engagements. As a rule,

these fine [.250"- 40 TPI] screws will

come out with very little resistance.

But when thread damaged, galled, or rusted, they will not. Screwdrivers roll

out, slots damage easily, and nickel

plated screws look all the worse. With

late crane lock screws, a good rule is:

when stiff or resistant, skip the impact

step- use the drill press or screwjack

method to get them out. See figs.

9&10. A Handy Bench Block You

may get only one chance to remove a

stuck screw. A bench block-levelling

support is needed when using screw

slot impact and/or screw slot pressure to loosen a thread. The work must be

held at 90 degrees to the screwdriver

bit, so the working force is not

weakened or diverted. A non-abrasive

bench block placed under the frame

can also help preserve the finish. The

block is easiest made from nylon or

Teflon, but much longer lasting when

made from aluminium. See figure 8. A

two-sided block handles D and E/I

frames.

Figure 7- Shows a late style crane lock screw installed in a late

model frame. These screws are larger in diameter and are

recessed on the inside to receive and guide the late type lock

detent and spring. The detent and spring are located directly

under the lock screw. The late crane lock subassembly is

illustrated below.

Figure 8- Illustration shows a bench and shop levelling support

block used to hold the frame at 90 degrees to the screwdriver

blade when impact loosening resistive screws, or when using a

screwjack or drill press to remove frozen screws. These blocks,

easily made from plastic or aluminium, also help protect frame

finish.


Figure 9- Shows a frame set up on a drill press table for stuck

screw removal. The frame is supported on an aluminium

levelling block. A correctly fit hollow ground Magna-Tip

screwdriver blade is chucked in the drill press and held in the

slot with firm down pressure. The screw is then hand twisted

out. See Fig. 10.

Figure 10- Shows a bench set-up for frozen screw removal,

using a basic screwjack. This tool removes any screw with

enough slot area that can be addressed at 90 degrees and that is

not rust welded. The top section of this screw jack is from B-

Square. The base was replaced with a larger plate to hold a

levelling block.

Removing Stuck Screws

Generally, most stuck and resistant

screws aren't rusted, galled, or cross

threaded at all, but just cemented in

with a mixture of dried oil varnish and

hardened dirt. With the tougher

resistive cases, begin by pre-immersing the entire revolver [less the

grips] in a penetrating oil. Typically, a

really frozen screw will be found with

damaged and/or rusted threads as well.

With these, the removal methods

shown in figs. 9 & 10 are the only way

to get the job done. When screw slots

have been damaged, but enough of the

head still remains, use an extra narrow

cape chisel to re-establish the slot.

Caution: Don't use heat to loosen stuck or frozen screws. Warming the

frame slightly before immersing it in

oil has seldom helped. If taken too far,

heat treat will be altered and frame

finish damaged. Removing Broken

Screws Occasionally, you may find a

severely damaged or broken screw

head left behind from a previous

removal attempt. If what's left of the

head won't rotate, nothing can be done

until it is removed. These are the

remedies:

1. For sideplates and old style crane

screws: align the frame and mill

to the bottom of the original

counterbore.

2. With late style crane screws: first

allow for thread diameter, and

then mill just enough to release

the detent inside. After that, mill

only enough to clear the old

screw 3. Then, on exact original centre,

drill to tapping size and re-tap

the threads.


Remove Crane and Cylinder

Assembly

When the crane is fully open, rearward

movement of a Colt D, E, and I frame

cylinder is additionally limited by the

cylinder stop lug on the outer wall of the sideplate. This is particularly true

with late style cylinder assemblies.

With these, when the front section of

the ejector rod has been unscrewed,

the stop lug is the sole retainer when

the cylinder is swung out. Colt D, E,

and I model crane and cylinder

assemblies were designed for removal

while together by simply drawing the

combination forward and off the

frame, after removing the crane lock detent. For this reason, Colt's D.A

revolver cylinder flutes are just a bit

longer than other revolvers. Flute

lengths will vary between models and,

as well, between early and late

cylinder types, but are always just

long enough to allow for crane guide

clearance at the front of the frame.

1. After the crane lock screw and

detent have been removed, hinge

the cylinder open until the crane stop rests on the frame.

2. Rotate the cylinder to align the

closest flute with the raised crane

guide at the front of the frame.

3. Then draw the assembled crane

and cylinder straight forward and

out.

4. If necessary, lift up slightly as

the crane stem clears the frame.

5. If the crane stem is resistant,

loosen by working in a few drops of oil before drawing the stem

out.

Figure 11- Shows a Colt Diamondback cylinder and crane

hinged out 90 degrees, with the crane stop against the frame.

The assembly is now ready for removal. When the sideplate is

on, Colt D, E, and I frame double action revolver design

requires that the crane and cylinder assembly be removed from

the frame together.

Figure 12- Shows an early Colt Official Police model cylinder

at the 90 degree open position. The bottom cylinder flute recess

is lined up with the crane guide extension on the frame, so that

the cylinder will clear as it is withdrawn. The crane and

cylinder assembly are now ready to pull straight forward, and

off the frame.


Figure 13- Shows an I frame revolver ready for sideplate screw

removal. The screwdriver blade shown below has been hollow

ground to exactly fit the screw slots. The blade edges have

been trimmed and dulled to prevent damage to the sideplate.

Circular gouges around sideplate screws are both unprofessional and unsightly.

Figure 14- Shows the correct strike zone for removing snug

Colt revolver sideplates with impact vibration. The grip frame

is rapped sharply to set up the vibration necessary to overcome

the mechanical friction holding the sideplate in position.

Warning: prying sideplates off can flare edges and may bend

the plate.

Remove Sideplate Screws

Sideplate screws are found in every

possible condition and tightness.

Screws with heads intact will usually

unthread easily. Removing sideplate

screws with rounded-off heads or

blurred or otherwise damaged screwdriver slots always requires extra

care.

1. Grind screwdrivers to fit before

use. See figs. 3 & 13.

2. If a screw is resistant, add oil

around the head. Rap the

screwdriver handle and then

twist, applying firm down

pressure with the blade held

squarely in the screw slot. 3. When stuck or frozen, see figures

9 and 10 for removal.

About Sideplate Removal

Since the removal of any double

action revolver's side plate is a basic

and simple job, it might seem that

very few would be found in a flared,

dented, or otherwise damaged

condition. But that isn't always the

way it is. Non-professionals still

manage to pry and drop damage side plates with some regularity. And,

sometimes, the problem is worsened

when damaged plates are reinstalled

without straightening or refitting.

When a damaged sideplate is forced

back on, particularly one with an edge

dent, repair becomes a bit more

involved because the original damage

then transfers to the frame. Early Colt

revolver sideplates are hand fit and

must be removed with care. The rule is: Never pry on a sideplate. See

figures 14, 15, and 16. Since the

beginning, the best sideplate removing

tools have been: a wooden hammer

handle and your left thumb.


Remove Sideplate

1. After the screws have been taken

out, begin side plate removal by

holding the frame firmly, with

the plate side facing up.

2. Place your thumb on the sideplate and latch to prevent

bounce, parts loss and sideplate

damage. See figure 15.

3. Hold the revolver over the bench

to prevent damage. In the event

the sideplate escapes your grip, it

won't land on the floor.

4. Sharply rap the grip frame, using

the wood handle of a 6 or 8

ounce ball peen, or brass

hammer, as shown in figures 14 and 16. When correct impact is

used, the sideplate will easily

vibrate up and out of its frame

recess without edge damage.

5. Damaged, forced and/or oil stuck

sideplates usually require much

sharper impact vibrations to

loosen. Being harder, a plastic

screwdriver handle will impart a

higher vibration and do the job.

About Early & Intermediate D, E,

and I Sideplates

Even though machined, these

sideplates were factory hand fit to a

hairline junction with their frames.

Some of these sideplates may have

been in place since the beginning of

the century, and will require higher

impacts to loosen. Without thumb

pressure on the sideplate, they can be

easily chatter nicked as they separate. This caution is of particular

importance with early collectibles,

since the extremely flat sides and

unforgiving mirror finish on many

early models will show even the

slightest blemish.

Figure 15- Shows thumb retaining both latch and sideplate,

with the plate ready for removal. A light pressure keeps the

sideplate and latch from bouncing off. In this way, plate

damage is prevented, and the latch, spring, and guide will not

be dropped or lost. This tension also holds the sideplate and

prevents frame edge nicks.

Figure 16- Shows a frame being held in the "latch retained"

position. A wooden hammer handle is used to impact loosen

the sideplate. The wood handle creates a softer vibration,

which helps minimize edge damage as a tight sideplate springs

free. This is important with highly finished early and

intermediate models.


Compress early wide-knee mainsprings before removing.

Figure 17- Shows a late type E/I mainspring being slipped

sideways at the spring knee for removal from the frame. Except

for size, late D and E/I mainsprings are quite similar. Early D

and E mainsprings [wider at the knee] should be compressed,

as shown, before removing. Offset needle nose pliers are useful for this job.

Figure 18- Shows cylinder hands now ready for removal in an I

frame, at left, and a D frame, at right. Tension on the hand is

relieved by lifting the rebound lever slightly. Removing the

hand at this time drops the rebound lever and its cam away

from the cylinder bolt tang, and makes rebound removal easier.

Remove Mainspring

With the sideplate off, the next step is

to remove the double leaf mainspring.

Late type mainsprings are easily

removed by first pushing the spring

knee out of the frame, and by then catching the spring's rebound leg with

a thumb. With early wide knee type

mainsprings this is difficult to do, and

is not recommended, because it places

undue torque on both the main spring

connector fingers and the hammer's

stirrup. Being hardened, the

mainspring fingers are the first to

fatigue and break. Compressing the

spring first allows removal without

bind or torque. See figure 17. 1. Compress old style springs at

centre, and just enough to allow

easy movement.

2. Hold compression, and unhook

the connector fingers from the

hammer stirrup. Then remove the

spring.

Remove Cylinder Hand

Once the mainspring has been

removed, the rebound lever and hand are no longer under tension.

But, with well fit actions, the rebound

lever's cam will be in contact with the

actuator tip at the bottom of the bolt

tang. The hand is removed at this time

to drop the rebound lever away from

the bolt actuator tip. See fig. 18. The

hand is easily removed by lifting the

rebound lever and drawing the hand

up and out of the frame. Since we're

dealing with critically fit action parts, always make sure the hand is kept

with its parent frame and other mated

parts.


Remove Rebound Lever and Pre-

check Pivot Pin Fit

The rebound lever should be removed

after the hand. Taking the hand out

first relieves all tension from the lever

during removal of the rebound pivot pin, and allows a pre-check of rebound

pivot pin fit in the frame. A tight, or

extra tight, pivot pin usually indicates

that the pivot pin hole is distorted or

the frame is slightly bent or tweaked at

the pin hole. There are two rebound

pivot pin sizes: E/I frame pivot pins

measure about .120" in diameter,

while D frame pins measure just at

.100". Examine these pins closely.

When undersized or short, pins can slip to one side of the frame- and

especially in the thinner grip frame D

models. Also, incorrect and poor

fitting grips may let a loose pin move

to one side. When this happens, the

usual result is that mainspring pressure

then cants and binds the partially

unsupported rebound lever. At that

point, action function frequently

becomes erratic. In some cases, action

jams can result. This subject is

discussed now, because pin fit must be checked at this time, and particularly

if the revolver has a history of odd

action problems, jams, or was found

erratic on the original action pre-

check. The usual cause of odd rebound

problems with D frames is a wrong

pin and/or poor fitting grips.

Sometimes, a loose pin, if long

enough, will be retained on centre if

the correct grips hold it in place.

Figure 19- Shows a late I frame positioned on a bench block.

The snug rebound pivot pin is set up for drifting out with a

1/16" punch. Pivot pins can range from snug enough to need a

tap to get them out, to slightly loose. Most can be punched out

by hand. Distorted frame pin holes are the usual cause of tight

rebound pivot pins.

Before reinstalling the rebound, frame tight pivot ends must be corrected

Figure 20- Shows close views of E/I and D type frames with rebound pivot pins pushed out. The pivot ends of both rebound

levers are offset, out of their frame slots, and now ready for

lifting out. Caution: When a pivot pin is found loose or too

short, make note of it, since the pin will have to be replaced on

reassembly.


Figure 21- Shows a close view of an E frame and hammer after

the rebound lever and pivot pin have been removed. The

hammer assembly has been rotated back far enough for firing

pin clearance and is now ready to lift up and out of the frame.

Being very similar, D and E model hammers remove in the same way.

Figure 22- Shows a close view of a late style D frame action

interior after the hammer has been removed. The trigger, safety

lever, and late style upper safety [safety hammer block] are still

in place. Late style hammers require that matching late style

upper safeties be used. Early and late style safeties are shown

above.

Remove Hammer

All D and E/I type hammers remove in

the same way:

1. Roll the hammer back far enough to

clear the frame.

2. Draw the hammer up and off the frame pin.

3. If resistant, place a drop of oil on

the pin and wobble the hammer up off

the pin.

About E & I Hammers-

The I frame hammer is a modified,

updated version of the older, standard

E type hammer and a very workable,

proven design in both service and competition. It was top end

remodelled by the factory in the

1950's for use in the original model

Trooper, .357 Magnum, and Python

actions. A larger, target positioned

S.A. thumb spur was added, and the

hammer mounted E type firing pin

was removed. The new hammer face

was redesigned to operate an in-

frame, inertial type firing pin, and yet

retains nearly the same safety stop

position. The E model upper safety was updated for use with the new I

model hammer.

Early & Late D Hammers-

D frame hammers divide into two

basic subtypes: an early and a late

style. This is discussed here because

there is a corresponding [early and

late] difference in the safety, or

hammer blocking arm, of the safety system that secures these hammers.

Early D type hammer safeties can be

used only with early D hammers, and

late style D safeties only with late

style D hammers. They don't mix.

Watch for mismatched or make-fit

safety system modifications. Replace

any that you find.


Pre-Check Safety Assembly

Considering the upper safety

variations [hammer blocks] that have

been used in Colt's D, E, and I frames,

and with both safety and practicality

in mind, make the following safety and linkage pre-checks while the

trigger and safety parts are still in the

frame:

1. Does the safety assembly run

free, both in the frame and at the

boss pivot point?

2. Any drag or catch marks found

on the safety linkage, on the link

pins, or on the frame side of the

hammer? 3. Is the hammer pin boss low?

[Hammer riding safety?]

4. Is upper safety [hammer block]

position correct? Is alteration or

mis-fitting by others visible?

If any safety system problems are

found, replace the parts on

reassembly.

Remove Latch Pin, Trigger, and

Safety Assembly

1. If not already removed, take the

latch pin out now.

2. Lift up on the trigger and wiggle

the trigger and safety linkage up

out of the frame.

3. If the trigger and/or safety

linkage is sticky or resistant, add

oil, turn the frame over on the

bench, and rap the outside of the

frame sharply with a plastic

mallet. Never pry on a safety part.

This leaves the cylinder bolt, pivot

screw, and spring still in the frame. If

bolt function was correct on pre-

check, and if a detailed cleaning is all

the work that was intended, these parts

may be left in the frame. Otherwise,

they will be removed next.

Figure 23- Shows a late I frame with hammer removed, ready

for safety assembly pre-check. E and I frames have used the

#50489 safety lever throughout production. A small change

made in the original E upper safety to fit I model hammers

created the #51657 upper safety used in the Python and original

Trooper.

Figure 24- Shows an E frame trigger and its connected safety assembly linkage ready to lift out of the frame. Remove the

latch pin first to get it out of the way. Caution: if the trigger

and/or safety linkage binds, or doesn't lift out easily, don't use

force. Instead, turn the frame over and rap it sharply with a

plastic mallet.


Figure 25- Shows a close view of an E/I type cylinder bolt,

pivot screw, and bolt spring ready for removal. The bolt spring

is taken out first. Best tools for this job are a very small screw-

driver and an index finger. The screwdriver lifts the spring out

of its frame slot, and your finger tip prevents it from getting

lost.

Figure 26- Shows a close view of the smaller D cylinder bolt

assembly. A thin jeweller's screwdriver can be used to lift out

the bolt spring in this frame. Note: with very little room to

work in, the D bolt spring is easier removed after the bolt pivot

screw has been taken out. D type pivot screws are larger and

easier to unscrew.

Remove Cylinder Bolt Spring

The small, 1/2 round groove milled

into the frame just above the trigger

window is the cylinder bolt spring

seat. Bolt spring position is fully

retained when the trigger is installed

in the frame. Remove spring as follows:

1. Lift the bottom of the spring up,

out of the frame, while holding

the end with a finger. See figs.

25 and 26.

2. Slip a small screwdriver blade

between the coils, and then draw

the spring out.

Remove Bolt Pivot Screw

The only possible difficulty involved

with this usually very simple job

hinges on the condition of the cylinder

bolt pivot screw. These thin screw

heads and shallow slots need more

than a little care. A correctly fit

screwdriver blade is required, as well.

This little screw usually gives you

only one chance at it before the slot

blurs out.

1. Grind your screwdriver to a

perfect slot fit.

2. Place a few drops of oil around

the bolt assembly, install the

screwdriver, rap the handle, and

twist loose.

3. If resistant, don't try hand

loosening the screw.

4. Soak the frame in a thin

penetrating oil mixture. Then

sharply rap the outside of the frame with a plastic mallet.

[Vibration usually helps.]

5. Then, use a screwjack or press to

get the screw out.

Remove Cylinder Bolt

With the spring and bolt pivot screw

taken out, push the bolt head back

through the frame, and then lift out.


About I Frame Firing Pins

The I type, inertial firing pin is

removed before re-finishing the frame

and also when the revolver is

disassembled for detailed parts

inspection and refitting work. Just making an external firing pin tip

inspection is not enough. Checking

extended firing pin length by pushing

the pin forward and measuring tip

protrusion is a necessary step, but

useful only with the right pin. Nothing

can substitute for proper visual

inspection of the firing pin, spring,

and stop plate assembly. Periodically,

careless gunsmiths have been known

to mis-install the small diameter #580451 [J frame] firing pin in I

models; either because the pin will

easily drop in, or because their parts

stock has been hopelessly mixed up.

For whatever reason this is done, this

parts switch is one way only- the I pin

is too large in diameter to fit in J

frames. Also see figure 121.

Remove I Frame Firing Pin

Remove the I frame firing pin as follows:

1. While holding medium thumb

pressure on the rear sight body,

loosen, or fully back out, the

elevation screw.

2. Drift out the mounting pin and

remove the sight leaf body. See

figure 27. Watch for the two

elevation springs as you remove

the sight. 3. Depress the firing pin with an

1/8" punch, just enough to clear

the stop plate, and then draw the

plate up. Catch the pin and

spring with your thumb as they

clear the stop plate.

Figure 27- Shows a Colt Accro adjustable rear sight, used on

both I frame and Diamondback models. With I frames, the rear

sight leaf body is removed first to gain access to the inertial

firing pin, spring, and retaining stop plate mounted just

underneath. Remove the firing pin assembly with an 1/8" punch, as shown.

Figure 28- Shows a detailed view of an I frame firing pin

tunnel, after the firing pin has been removed. The firing pin.

spring, and stop plate are shown, at right. Don't skip this

disassembly step. The firing pin must be checked both for

condition and to be sure it is the correct part [not a substituted,

smaller diameter, J pin].


Figure 29- Shows an early style cylinder latch being removed

from the sideplate. The back of the thumbpiece on early style

latches was factory fit to the sideplate with very little

clearance. Latch friction marks usually appear on the sideplate

just to the rear of the thumb piece with the latch in the closed

position.

Figure 30- Shows a sideplate and late style latch assembly. The

latch spring and latch spring guide are shown still in the frame.

With late style latches, friction and drag have been eliminated

by increased clearance at the back of the thumbpiece and by

factory installation of a nylon bearing insert under the

thumbpiece.

Remove Latch, Latch Spring and

Guide

If, on initial pre-check, the latch

seemed sticky or was too tight, always

look for rust under the latch and/or

friction marks on the sideplate,

especially when dealing with closely fit older style cylinder latches. See fig.

29. Also, dried, impacted oil and dirt

build-up around the latch pin and in

the guide slots of the sideplate can

cause a latch sticking problem. Later,

when all parts are detail cleaned, give

extra attention to these inside areas.

Look for mechanical friction and drag

marks. If marking is present, and the

latch is too tight, or the sideplate slots

or latch rails appear to have been peened, make a note of it. Note it also

if the latch is too loose. In both cases,

latch refitting or replacement could be

required. See later sections on cylinder

latch fitting. With late style latches,

make sure the nylon bearing insert is

still in place under the thumbpiece.

See figure 30. Remove the latch spring

and guide and place them in the parts

box with the latch. Note if the latch

spring was overly tight or hard to get

out of the sideplate. If resistance was not caused by dried oil or grease, the

pin tunnel may require clearance

reaming on reassembly. After latches

have been fit, and particularly if once

tightened, always keep them with their

correct sideplate and frame. Mixing

them up creates extra refitting work.


About D, E and I Frame Pins

From the beginning of model

production, Colt's D, E, and I revolver

frame pins have been factory

installed by press fitting them into

their frames. Extra precision machining steps are involved in

manufacturing revolvers in this way,

rather than by simply brazing the

pins in. The result, subject to the

later condition of the frame, is a field

serviceable, and re-buildable,

revolver. Even with this easy

replacement factor built in, these pins

are so well dimensioned and fit that

the bearing surfaces seldom wear

out with average use. Don't remove frame pins at this time unless the pins

are rusty, pitted, damaged, or

excessively worn and require

replacement. See Section II for frame

pin removal. If the revolver is

being disassembled for re-finishing, I

suggest hand polishing the frame and

pin extensions, rather than

removing the pins. Leaving the

pins in place prevents unnecessary

frame pin hole wear. Caution: When

frame pin holes are found loose, return the frame to the factory for

inspection and installation of an "SK"

or oversized pin.

About Pinned Front Sights

The rule is: Leave pinned sight

blades as they are unless replacing

them. This helps limit wear

enlargement of the barrel's pin

holes. When re-finishing, I suggest sand blasting and re-bluing with

sight and pins still in place.

Neutralizing solutions handle bluing

salt bleed-out.

Figure 31- Shows an I model with trigger and hammer frame

pins remaining after all action parts have been removed. D pins

are similar except smaller in diameter and on nominal 1.00"

centres versus the nominal 1.250" centres used in E and I

models. Frame pins are removed at this time only if worn

undersize, or defective.

Figure 32- Shows the double retaining pin front sight system

used on all Pythons. Sight blades on 6" Diamondbacks are

retained with one pin. Except O.M. Target and Match, other D

and E models, including the 4" Diamondback, have forged, or

welded and ground, blades. Remove sight pins only when

replacing the sight blade.


Figure 33- Shows a half-sectioned cutaway view of a typical early style cylinder assembly. Early style

ejector rods combine the forward rod and a multi-splined ejector stem in a single piece. The raised spring

flange at about midpoint serves the same purpose as the rod bushing does with late style rods. Warning:

Prevent damage by identifying early D, E, and I ejector rods- before attempting to twist out a nonexistent

front half section. The best identifier with early rods would be the shape of the rod head, and the fact that

the head unscrews. With early cylinders, the ejector star/ratchet is unscrewed to separate the crane/ejector assembly from the cylinder. Intermediate stem guides are pinned in place.

Figure 34- Shows a half-sectioned cutaway view of a late style cylinder assembly; identified by its pre-

machined and pressed-in stem guide. Late style D, E, and I ejector rods are built in two sections: a front

rod with fixed head, and a separate ejector stem with one spline and a fixed ejector star/ratchet at the rear.

With this design, only the front half of the rod needs to be unscrewed to separate the crane assembly from

the cylinder. The ejector star/ratchet should not be unscrewed. A separate ejector rod bushing is used with

late style rods, since the raised spring flange is no longer part of the rod stem.


Disassemble Early Style Crane and

Cylinder Assembly

Before disassembling an early style

crane and cylinder, see illustration and

caution about one piece rods in figure

33.

Remove Ejector Rod Head

1. Secure the ejector rod head

between bronze vice jaws so that

it can't slip. See figure 35.

2. Loosen and remove the ejector

rod head by turning the cylinder

body counter- clockwise [as

viewed from the rear of the

cylinder]. 3. If the head is rust stuck, or the

rod feels springy- and about to

shear, soak assembly in

penetrant. Break rust bond by

sharply rapping the top of the

ejector rod head with an 8 ounce

brass hammer.

4. Then, repeat step #2.

Note: As an assist when dealing with

stuck rod heads, even though all early

ejector rods were made with multiple stem splines to take the load, always

insert empty shells in every other

chamber to help cushion the twisting

force.

Remove Ejector/Ratchet

1. Secure the cylinder between

aluminium vice jaws, or chuck it

in a cylinder clamping fixture.

See fig. 36 2. Push the ejector rod up, holding

the fingers just high enough to

clear the cylinder. Install the

ratchet wrench.

3. Then, unscrew ratchet in a

counter clockwise direction [as

viewed from the top].

4. With resistant threads, soak

cylinder in penetrant, then rap

the closed ratchet face with a

brass hammer. 5. Repeat steps 1 through 3.

Figure 35- Shows an early style crane and cylinder assembly,

ready for rod head removal. Clutch the head between bronze

vice jaws, and use the cylinder body as a handle to increase

thread leverage. Loosen the rod head by turning only in the

above direction. Prevent rod bend by centering cylinder and

rod when twisting.

Figure 36- Shows an early style crane/cylinder assembly

chucked in a clamping fixture, now ready for ejector

star/ratchet removal. A ratchet wrench is shown above. This

tool allows the revolversmith to see the ratchet as it turns, and

exerts even pressure on the ratchet base without compressing

the ejector star fingers.


Figure 37- Shows an early crane and ejector rod assembly

being taken out of the cylinder after the ejector star/ratchet has

been removed. Sometimes, the ejector stem is found slightly

compression flared where it joins the back of the ejector star.

Unless dressed, the stem may resist being drawn through the

spline guide.

Figure 38- Shows a close cutaway view of an early style crane

barrel and threaded crane bushing, before the bushing is

unscrewed. Note that early style one piece ejector rods extend

past the crane bushing. A counterbored spanner is required.

Condition of the bushing's spanner slots must be checked before bushing removal.

Remove Crane/Ejector Rod

Assembly

In early style cylinders, the crane,

ejector rod, and spring subassembly is

retained in the cylinder by the

threaded ejector star/ratchet.

1. Once the ratchet has been

unscrewed, the crane can be

drawn forward and out of the

cylinder. See figure 37.

2. If the end of the ejector stem

catches on the cylinder's spline

guide as it is pulled out, it is

likely that the end of the stem

has been enlarged a bit by

compression flaring. Don't try to force it out.

3. Instead, push the stem back

through the guide and lightly

dress the flared material back to

flush with a fine Arkansas stone.

4. Then, clean and oil the ejector

stem and slip the crane out of the

cylinder.

Check Crane Bushing

1. First, check condition of the spanner slots machined into the

end of the bushing. See figure

38.

2. Next, check for rust. Soak in

penetrant if present.

3. If the slots are blurred or

damaged, they may require

careful redefinition with a thin,

specially ground chisel. When

doing this, remember to relieve

the inside corner of the chisel to protect threads inside the crane.

Note: Using pin punches to rotate

crane bushings out is the usual cause

of both bushing slot and inside crane

thread damage. Don't use punches.

Instead, always use a bushing spanner

wrench for this job. See figure 39.


Remove Crane Bushing

If the crane bushing is not rusted, and

spanner slots are in good condition,

bushing removal is an easy job. See

figures 38 and 39.

1. Place a drop of oil in each bushing slot to lubricate the

threads inside the crane.

2. Insert the appropriate D or E/I

size bushing wrench.

3. Push the wrench in to seat

spanner studs, then twist the

crane bushing out in a counter

clockwise direction.

4. If the bushing is resistant, soak

the crane assembly in penetrant.

Then, repeat steps 1 through 3.

Disassemble Late Style Crane and

Cylinder Assembly

Late style crane and cylinder

assemblies separate quickly by

unscrewing the forward portion of the

ejector rod. See figure 40.

Usually, when ejector rods are kept

moderately snug, cylinder rotation

alone will prevent loosening. Unless

an ejector rod has been over torqued, most are easily removed by either

turning the rod clockwise, or turning

the cylinder opposite normal rotation.

See fig. 40.

Caution: The ejector/ratchet stem

spline must be fully supported when

loosening a late style ejector rod that

has been overly tightened or is

otherwise resistant or stuck. Back-up

support is provided by installing a dummy or empty shell in every other

chamber to support the spline while

twisting the rod loose.

Figure 39- Shows a crane bushing spanner wrench, or "bushing

wrench" for short, being correctly used to unscrew an

early/intermediate crane bushing. A combination D/E/I

[double- ended] bushing wrench is shown above. The two

wrench sizes fit all D, E, and I model crane bushings. Check spanner slots before using.

Figure 40- Shows a late style ejector rod at top. A late cylinder

and crane assembly is shown below, ready for ejector rod

removal. I suggest chambering dummy rounds to protect the

single spline used in late style cylinders. Rotating the cylinder

counter clockwise, or the rod clockwise, [viewed from the rear]

will loosen the rod.


Figure 41- Shows removing a late style crane from the

cylinder, at "A", above. At "B", a late style ejector star/ratchet

and stem is being drawn out of the cylinder. It's a good idea to

pre-check the condition of the ejector star fingers and note

whether both ejector star guide pins are in place as the star is being removed.

Figure 42- Shows a late style crane assembly removed from the

cylinder. Except for a few early I models, the same crane

bushings are used in early and late cranes, #56099B for D

frames and #50349 for E and I frames. In late style cranes the

threaded bushing retains only the ejector rod bushing and

ejector spring.

Remove Late Style Crane Assembly

Once the ejector rod has been

unthreaded, late style crane assemblies

are no longer held captive in the

cylinder, and can be drawn out easily

with your fingers. See figures 40 and 41.

Remove Late Style Ejector, Ratchet,

and Stem

With the late style ejector rod

unthreaded and removed, the late

ejector star/ratchet and stem can be

drawn out, also with fingers.

Remove Crane Bushing, Late Style

Crane Assembly

Throughout production, Colt has used

only two standard crane bushings.

Early and late D and early and late E/I

bushings remove in the same way with

the same tooling. See figures 38, 39,

and 42.

Remove Dried Oil Varnish

If the frame, cylinder, crane or any of the action parts are varnish coated,

pre-soak them in solvent at this time,

so they will be ready for detail

cleaning and inspection which comes

next. Note: Dried oil varnishes and

impacted dirt can be very difficult to

remove with standard cleaning

solvents. With adequate ventilation, an

acetone bath can dissolve even the

toughest and most resistant coatings.

But, don't leave parts immersed more than an hour or two, due to rust

potential from solvent moisture

absorption.

Warning: Don't allow coloured sight

inserts, or other plastic parts, to come

in contact with such solvents. Always

wear rubber gloves.


Figure 43- Shows an I frame revolver with all parts removed except barrel, front sight, and frame pins.

These remaining parts are removed only when replacement makes it necessary. A cutaway frame and cylinder are used to show extra detail. The indicated areas are common to all D, E, and I frame revolvers.

Impacted dirt, dried oil residue, and varnish must be removed, and all surfaces and recesses well cleaned

before a detailed inspection of the frame, sideplate, and cylinder can be made. Important areas are

identified by number, below. Also, see figures 44, 45, and 46 for removal of heavy lead fouling.

1. Barrel, forcing cone, and surrounding frame area

2. Cylinder bolt window, underneath window, and inside the frame

3. Firing pin tunnel, recoil plate, and firing pin stop slots [I frame]

4. Latch pin tunnel and ratchet recess

5. Milled safety linkage slots and recesses

6. Milled cylinder bolt recess

7. Crane stem tunnel and crane lock recess

8. Frame screw threads, all locations

9. Sideplate slots, latch recess, and spring tunnel

10. Front cylinder face, around chambers

11. Cylinder crane tunnel and splined stem guide

12. Ejector star recess and around ejector guide pins

13. Chamber leads/throats


Figure 44- Shows a Lewis Lead Remover ready for use in a

.357 barrel. This superb tool uses brass screen patches over an

expandable rubber head and mechanically removes even the

heaviest leading without the use of abrasive materials or

poisonous chemicals. Lewis Lead Remover and rod are shown

separately, below.

Figure 45- Shows a Lewis tapered forcing cone head installed

and set up for lead removal. It works by rotating the brass

screen covered head while pulling forward on the rod. In

magnum revolvers, forcing cones may be subjected to extreme

combustion temperatures, pressures, flame erosion, and

carburizing. See figure 52.

Heavy Lead Removal

When soft lead and soft alloy bullets

are fired, a certain amount of bore

streaking is normal and unavoidable.

This is still the case when bullets are

correctly sized and lubricated. Normal

streaking presents little problem, and is easily removed with standard

solvents and cleaning brushes. But

heavy leading and build- ups, of the

type that make bores look like the

inside of a lead pipe, shouldn't be

allowed to happen in the first place-

bore rifling becomes useless, bullets

tear, accuracy is lost. The remedy for

this problem is prevention: Don't

accelerate soft alloy lead, even when

well lubricated, faster than 850 or 900 fps. For .38 special target use, 700 to

750 fps. is optimum. With proper

bullet lube, bore leading is usually

minimal.

As magnum velocities are approached,

the much higher gas temperatures

vaporize the backs of lead alloy

bullets and coat the inside of the

barrel. Since reloaders insist on

loading high velocity soft lead

ammunition, the removal problem

continues to exist. The following barrel de- leading method is still best:

1. Install the correct bore size

Lewis Lead Remover expander

head and brass screen patch. See

figure 44.

2. Draw the patch through slowly,

with the rubber expander head

set just at lead build-up size.

3. Then, expand the head slightly

with each drawing of the patch, increasing bite.

4. Continue until all fouling has

been flaked off.


De-lead .357 Cylinders

The lead and/or carbon rings that

usually build-up from firing .38 spl.

rounds in .357 cylinders should be

removed regularly- for three reasons:

1. When .357 rounds are fired in

minimum headspace revolvers,

the accumulated lead and/or

carbon ring can act as a crimping

shoulder. Bullet deformation and

dangerous, excessive gas

pressures are typical results.

2. Even small carbon rings can vary

pressures when .357 ammunition

is fired.

3. Moisture tends to absorb into the carbon layers, pitting the

chamber walls.

Detail Inspect Cylinder

At this point, we are only

concentrating on the body of the

cylinder. Other cylinder parts will be

checked later. Make the following

checks:

1. Inspect the cylinder collar. The

shoulder must be square, smooth and unaltered.

2. Check the front of the cylinder

for nicks, dents and "cylinder-

hits-barrel" rings.

3. Check the cylinder face at exit

throats for scrub-out, or

rounding, from abrasives.

4. Inspect chamber interior

condition for pits or damage.

5. Check that both ejector star

guide pins are there, are high enough, and undamaged.

6. The spline guide should be

undamaged. Late style press- fit

guides must be tight.

7. Inspect cylinder bolt slots- all

must be like new.

If enough material remains, cylinder

collars can be refit after stretching.

Ejector star pins can be replaced. If

any of the other problems are found, replace the cylinder.

Figure 46- Shows a half-sectioned cutaway cylinder and

interior chambers. Arrows show leading zone. When .38

special cartridges are fired in the longer .357 magnum

chamber, lead and carbon build up between the .38 special case

mouth and the chambers' exit throats. A Clymer de-leading

reamer is shown at bottom.

Figure 47- Shows front, rear, and inside cylinder inspection points which must be checked after the cylinder has been

cleaned and de-leaded. This necessary, overall inspection will

determine whether or not the cylinder can be used as it is, or

whether fitting work and/or cylinder replacement will be

required.


Figure 48- Shows frame and sideplate completely cleaned and ready for close inspection before

reassembly. Carefully inspect and detail all areas listed below, as necessary. Frames and sideplates that

are in substandard condition due to internal rust, alteration, cracks, or other damage, will not produce a

safe, quality product, and must not be used. Also, see figures 49, 49A, 50, 51 and 52.

1. Firing pin tunnel or slot- check for hammer flanging, remove burrs

2. Latch pin tunnel- inspect for alteration, remove edge burrs

3. Bolt window- inspect for alteration, remove burrs, do not oversize

4. Forcing cone- check condition, if eroded or cracked, see figure 52 5. Recoil plate, D&E- check plate, firing pin port for flush, level as needed

6. Crane tunnel- inspect, lightly dress with Craytex rod, don't oversize

7. Frame pins/bosses- check tightness, correct pin type, alteration, or wear

8. Frame threads- inspect all threads, re-tap any in question

9. Frame sideplate recess- check edge condition, remove nicks or burrs

10. Rebound pivot pin holes- check for moderately snug pin fit

11. Sight/firing pin stop slots, I frame- inspect, remove edge nicks, burrs

12. Barrel/frame fit- check that barrel is at 12:00, and tight in the frame

13. Sight condition- inspect blades, pins, and screws as applicable

14. Crown and bore- check crown for nicks, dents, damage- inspect barrel for wear, rust, bulges or

obstruction See figures 53 and 54

15. Interior frame condition- inspect interior slots and recesses, remove burrs and level high contact areas

16. Sideplate- check for straightness, check latch slots, remove any burrs


Figure 49- Shows close views of a ratchet-peened frame. Peen marking is most often found in magnum

revolvers, but can also occur in .38 spl. steel and aluminium alloy frame revolvers when over pressure

ammunition is used.

The use of hot, high pressure curve loads, alone, can create excessive cylinder endplay. The forces and

pressures involved can stretch frames and compress cylinder collars in fairly short order.

Excess endplay, when combined with the continued use of heavy loads, sets the stage for the beginning of

ratchet peening problems. With heavy loads, ratchet indentations begin to appear quickly after excess

cylinder endplay develops; just how soon is subject to now much inertia the cylinder is forced to pick up.

With high pressure loads as the driving force, the determinants are: how far the cylinder is allowed to

move forward (existing endplay), how hard it strikes the frame (cylinder collar compression and more

endplay), and, finally, how much energy the cylinder has on return when it impacts against the back of the

frame.

Early style D and E frames were made to use standard velocity ammunition. Per the factory, aluminium

alloy D frame revolvers were made for standard velocity ammunition but can fire +P rounds on a very limited basis. Keep in mind that alloy frame revolvers were originally designed primarily for lightweight,

law enforcement concealment purposes. No revolver of this type by any manufacturer was made for

continued use of even standard velocity ammo. Reasonably, if the use of +P ammunition is this restricted,

then it logically follows that none of the above revolvers were designed to fire even one round of + P+ (or

similar) ammunition. Caution your customers about this.

The following are the basic mechanics of ratchet peening:

1. Shell casings push back on the recoil plate on pressure rise. Expanding gas then accelerates the

cylinder forward. The faster the pressure curve, the greater the speed and energy the cylinder

will develop.

2. At the end of forward travel, the cylinder collar impacts the frame. 3. At about this time, the bullet exits the cylinder and enters the barrel. Hot, expanding, high

pressure gas is suddenly vented out through the barrel/cylinder gap. The cylinder is shot

backward, and the ratchet strikes the frame with high energy, very much like a punch press die.

The frame then dents, or is "peened" at the points of ratchet contact.

The rule is: Don't begin refitting work on any revolver with ratchet peening indentations. Send the

frame to the factory for inspection and/or replacement.


Figure 49A- Shows two frames with evidence of moderate ratchet-peening at the ratchet seat. But,

interestingly enough, both frames have been pressure distorted and pushed back. Extreme over pressure

loads have exerted enough force to push the backs of both frames out of shape. As is many times the case

when such loads are fired long enough to heavily peen the ratchet seat, frame warpage also distorts

sideplate fit. The steel frame and sideplate, at left, are similarly distorted. Fortunately, it's not often that

you will see an aluminium frame in the condition shown, at right. But when you do, the frame will be

cracked in other places, as well.

If not for Colt's superb frame strength, the safety factor built into most cartridge cases- and probably dumb luck, the gross overpressures necessary to do the above kinds of damage might not have been

contained. What the owners did with both revolvers was to simply pressure-destroy the frames before

they could ratchet- peen them to death.

Usually, by the time the moderate ratchet-peened stage is reached, most pressure abused revolvers are

found to have other pressure related problems, making frame replacement economically unrealistic.

Typical additional damage is:

1. Excessively stretched and/or cracked frames and tweaked sideplates

2. Compressed cylinder collars and sprung cranes

3. Damaged cylinder ratchets, guide pins, ejectors, stem splines, etc. 4. Eroded, cracked, and/or blown forcing cones

If, from a liability viewpoint, there is any question about the condition of a frame, or about saving an

individual frame, I suggest shipping the revolver to factory service for inspection and an official opinion.

Stress the importance of this to your customer- since his safety is involved.

Generally, people who ruin revolvers can generate countless reasons to explain how "it" happened. These

characters seldom admit error. But, on the off chance that reality might filter through, show them pictures

in a book like this and chew them out. Who knows, it might work! Also see safety warnings at the end of

this section.


Figure 50- Shows an aluminium alloy frame with a broken top strap and with cracks under the barrel and

under the recoil plate. Alloy frame cracks just under the barrel can be caused by use of incorrect barrel/frame removal tooling in the field. However, the kind of frame damage shown above was caused

by firing rounds which exceeded the manufacturer's ammunition recommendations. Pressures generated

by these loads force barrels forward and expand frame threading. Alloy frames were not designed for

continuous use at all- or for more than occasional use with +P ammunition. Even one round of +P+

ammunition and/or similar over pressure reloads can rupture cylinders and produce frame cracks in both

lightweight and non-magnum steel frame revolvers.

Figure 51- Shows a steel frame revolver with top cylinder chamber and frame strap blown. The frame is

also cracked at the rear, and frame pins loosened. This damage was caused by firing a single round of

+P+ ammunition, which was abject foolishness. The fact is that high pressure/velocity +P+ rounds are

"restricted use only" ammunition. These loads are intended only for magnum revolvers and/or magnum revolvers with .38 Special chambers. Remember, in any firearm, built by any manufacturer, there is a

physical limit to material strength. Closely inspect all frames. Don't reassemble or refit any revolver with

a cracked frame. Note that "frame is unserviceable" on the repair order.


Figure 52- Shows a close view of a severely flame eroded and cracked forcing cone. The above barrel

was fired continually with hot, high pressure reloads. Setting back the barrel and re-cutting the cone did

not remedy the problem.

Most major commercial ammunition manufacturers load the .357 magnum cartridge with fast burning

powders in pressure ranges between 25,000 and 40,000 PSI [copper units of measurement], with many

commercial loadings considerably below 40,000 PSI.

Some reloaders are inclined to load the .357 magnum cartridge to even higher pressures and velocities,

raising chamber temperature dramatically. With high and extreme pressures, gas temperatures jump

sharply, reaching well in excess of 3000 degrees F even on a cool day. On a hot day, the same loads can

generate even higher temperatures and pressures, and, if not already dangerous, can become so.

This is the primary cause of forcing cone flame erosion and failure. These unreasonable loads abnormally

heat the forcing cone. With hot, high pressure loads, a problem in heat dissipation is reached at some

point in any magnum revolver- specifically, the inability of the mass to dissipate excess heat quickly

enough. The thinner outer areas of the forcing cone and rear barrel face suffer most. Carburization

brittleness, caused by slower burning powders and carbon from partial combustion reaching the forcing cone, further weakens the cone and adds to the overall deterioration problem.

Caution: Closely inspect all forcing cones, particularly in magnum revolvers- when found cracked or even

moderately eroded, the barrel must be replaced.


Figure 53- Shows a swelled barrel exterior and its half-sectioned front half, just below. The above barrel

was bulged when a .38 Spl. reload (with primer only- no powder) lodged a bullet partway down the bore.

Then, a second .38 Spl. round was fired into the obstruction. With obstructions in mind, don't fail to

inspect every bore. Also, always check bores for pitting, scratches, and/or possible wear at the thrust sides

and tops of the lands. Generally, worn lands appear shallow, shiny, and sometimes excessively concave.

But the real test for wear is made by either slugging, or casting the bore with Cerrosafe casting alloy and then measuring the slug. Replace barrels with worn, pitted, internally scratched, bulged or otherwise

damaged bores. See barrel replacement, Section II.

Figure 54- Shows a close view of two muzzle crowns. The I model crown, at left, shows no irregularity or

damage, and is in excellent condition. The other barrel shown at right is also in excellent internal

condition. But, the crown has several small nicks and a dent extending into a rifling groove that will

seriously affect accuracy. This muzzle will require re-crowning before completion of work. See re-

crowning in Section II. Don't fail to make this important inspection.


Begin Parts Checkout and Reassembly

This section details basic Colt D, E, and I frame revolver reassembly, while stressing the importance of

thorough frame and internal action parts pre- inspection. Parts fitting and refitting are fully covered, with

heavy emphasis on checking correct function and correct interaction of the parts. Replacement of worn,

misfit, and/or damaged parts is also discussed in this section. Additional parts replacement details are

included in Section II.

The information in this section covers late model D and I frame revolvers, as well as earlier and

intermediate D and E frame models. Where early and late style parts and mechanical differences exist,

they are illustrated and discussed in detail.

The fact is; when basic fitting [and refitting] work is done with care and precision, the final product can

be mechanically "as new" once again. And, when maximum attention is given to the same fitting details,

a revolver of match grade, or "blueprint" precision can be produced.

Factory non-availability of early style parts may limit repairs of some earlier models. For example, brand

new early style cylinders, cranes, and hammers are no longer made or available from the factory. Where earlier model and collectible factory discontinued parts are concerned, such as E model firing pins, check

with specialty parts suppliers such as GPC, West Hurley, New York. Fortunately, most late style parts, if

not direct replacements in their own right, will retrofit as parts assemblies within their respective models

and frames.

Always install new parts with extra care when fitting to older frames and to other, previously fit parts.

Even though current parts are 100% correct for their intended purpose, retro-fitting into older frames

usually requires much more attention to detail. Remember, we are talking about revolvers made as long

ago as 1905. Since then, there have been many downstream updates as well as slight variations in both

setup and gauging standards in the manufacture of both frames and action parts.

Parts originality, including correct finish, is important when repairing collectible and semi-collectible

early model revolvers. Dealers in older parts may be able to supply many needed items, but you must be very specific about the exact model the part is for and the finish style and condition that is desired when

ordering such parts. I've had very good luck with GPC. They probably maintain the world's largest

inventory of factory discontinued parts.

A great deal of factory consideration goes into manufacturing new parts that have the capability of retro-

fitting and replacing older similar parts. But there could be very little, if any, factory expectation that

early, non-current parts [i.e. those that are 30, 40, 50, even 80 years old] would be used in much later

models. For this reason, I strongly suggest that the use of such older parts [even if still in like new

condition] be limited strictly to the restoration and maintenance of the older models they were originally

made for.


Why all the emphasis on parts and parts checks?

Aside from excellent original design, materials, and metallurgy, the remaining factor that has made Colt

D, E, and I frame revolvers function so well and last so long is the superbly manufactured and well fit

parts that have been used in these models. Generally, very little actually goes wrong with unaltered

revolvers of these types. When it does, it is usually a simple thing- easy for the experienced revolversmith

to find and correct. But, sometimes the job is made harder by other items that may have been stoned, misfit, and even rendered unsafe by experimenters and non-professionals.

Since the beginning, all Colt action parts have been designed for multiple, yet simple function, with safety

and durability being of first importance. It is fair to guess that the main design theme must have been a

"John Browning style" economy of motion coupled with a minimum number of small parts to

manufacture. For this reason, D, E, and I frame revolvers use an absolute minimum of supplemental

springs, plungers, levers, pawls, dogs, and etc. Even the standard vee style mainspring used in these

models is responsible for three important functions: it spring loads the hammer, spring loads the rebound

lever, and also supplies trigger return pressure.

The rebound lever is another remarkable multiple function part. Its jobs include: disconnecting the cylinder bolt on trigger/hammer command, supplying forward ratchet pressure to the hand and return

pressure to the trigger, and lastly, rebounding the hammer rearward into the safety clearance position as

the trigger and safety return.

That the rebound is usually the most misunderstood part in this system is probably because its installed

position obscures half of its function. To the unfamiliar eye, it is very likely that the unusual shape and

multiple function of the rebound lever makes it seem complicated. But it isn't.

The seeming complexity of these very simple parts tempts the non-Colt qualified to go on guesswork with

these revolvers. For this reason, from time to time you will see one part, or another, altered by

experimental stoning. Sometimes, still continuing on guesswork, parts are experimentally changed. Often,

in these cases, the new parts are still found to be in need of final fitting. In a number of instances, by the time you see the revolver the original problem is still there; and worse, several new problems may be

piled on top of it.

Sooner or later you will see one of these compounded mistakes, but don't let it throw you. If the frame is

still serviceable, the revolver can be repaired. The sure road out of the mess is to follow these basic rules:

1. Always fully pre-check the action before disassembling.

2. Always keep parts separated, and with their original frame.

3. Always inspect individual parts for wear, alteration, and fit.

4. Always check proper mating and function of the parts as you reassemble- just as if you were

building a revolver from all new parts. 5. Always do a full function and safety check after reassembling.

6. If you find anything wrong on recheck- locate it, go back, and fix it.


Figure 55- Shows critical D, E, and I frame action parts. Any part that is either directly or indirectly

safety related, or that requires any amount of fitting to interact and operate safely and correctly with other

action parts, is a critical part. D and E/I mainsprings are included as safety related items because of their

direct interaction with the rebound lever- and secondary interaction with the cylinder bolt, hand, trigger,

and hammer safety assembly.

When ordering parts for D, E, and I frame revolvers, always specify model, finish, and the correct part

number. Read all update notices, particularly when late style, updated parts and assemblies are ordered.

Also, check parts lists for any supplemental, additional parts that may be required, such as the correct safety assembly to match a late style D hammer, etc.

While some parts, such as D, E, and I model bolts, hands, mainsprings, etc., have been used throughout

production of their respective models, other items such as crane lock detents, cylinder assemblies,

hammers, safeties, and some frame pins, have been updated.

Once a frame and barrel have been detail cleaned and have passed close inspection, reassembly and

checkout of cylinder and action parts can begin. However, if the barrel must be replaced, complete that

first, before beginning any other work. See barrel work, Section II.

Note: When replacing barrels, remember to leave excess barrel face material for later barrel/cylinder

clearance adjustment.


About Late & Early Cranes-

Early cranes are primarily identified

by their square cut detent slots. See

fig. 56 & 57. D and I cranes were

finally updated with the introduction

of the new style cylinder in the mid 1970's. Python model cylinders

updated officially at s/n #36190E.

However, a quantity of lower serial,

pre- produced I frames left the factory

with updated, late crane/cylinder

assemblies. D model production

updated with the depletion of old style

cylinder stock. E frame production

ended in 1969 with the original

Official Police Model- well before the

late style cylinder update. Earlier revolvers having late features will

have been updated at some time.

Check Early Style Crane

Before installing the crane:

1. Inspect crane flange for nicks or

dents. Lightly stone high spots.

Don't undersize.

2. Check lock detent slot. Remove

nicks or burrs. Dress lightly, do not undersize.

3. Check crane bushing threads

inside crane barrel.

4. If bushing will not thread in

easily, replace the bushing.

5. If crane bushing is still resistant,

chase threads with: .286"-48 tap

Std. D/E/I thds. .318"-48 tap for

SK o/s thds.

Check Late Style Crane

1. Check frame end of crane barrel.

Remove nicks, burrs, don't

undersize.

2. Inspect crane closure for frame

contact. Lightly dress.

3. Check crane lock vee notch for

nicks or damage. Lightly dress as

necessary.

4. Check crane bushing threads.

See #4 & #5, above.

Figure 56- Shows views of an early style crane, identified by

the square crane lock detent slot in the stem, and the standing

flange where the front of the crane barrel meets the frame. D

and E/I cranes were updated in two steps. Intermediate cranes

use the bevelled new style detent slot, yet retain the crane

barrel flange.

Figure 57- Shows views of a late style crane. With the early crane barrel flange removed, the longer, late style cylinder

collars now headspace directly on the frame itself, rather than

first bearing on the older crane barrel flange. The late style

crane stem has a vee-shaped notch to receive the late style

crane lock detent plunger.


Figure 58- Shows both early and late style crane lock detent

assemblies. Checkpoints are given above. Take extra care in

checking and reinstalling old style crane lock detents and

screws- these parts are no longer made. Since there is a risk of

thread damage, always start crane lock screws with your

fingers.

Figure 59- Shows a drill press installed tap aligning tool being

used to chase blurred frame threads. The frame is on a levelling

block. This method is used in chasing crane lock screw threads,

as well. Early style standard crane lock frame threads are

cleaned with a tapered .123"- 36 tap, and late style with a

.250"-4(J tap.

Check Crane Lock Detent Assembly

The most common problem with crane

lock assemblies is damaged threads,

see figures 58 and 59. However, the

following important areas should be

checked as well:

1. With early style detent

assemblies, make sure the lock

screw's extractor ring fits

correctly in the detent's receiving

slot. If nicked or dented, carefully

clean the extractor ring and/or slot

with a thin flex stone.

2. Check fit of the detent's

engagement shoulder where it

meets the crane stem. If an early style detent is worn, and a

replacement is not available, the

detent tip can be built up by TIG

welding and then re-faced. Also

see figures 60, 61, and 62.

3. Check the mechanical fit of the

lock screw and lock detent in the

frame.

Warning: never install an early detent

in the frame without the screw. If the

detent is pushed in all the way without the lock screw, it can be difficult to

remove.

Chase Lock Screw Threads

If the crane lock screw was tight or

resistant on removal, or the screw will

not readily hand start, lubricate, and

then clean the threads with a tapered

starting tap.

1. If a tapered starting tap will

thread in easily with fingers, clean

the threads by hand, then re-clean

with a bottoming tap.

2. If the tapered starting tap will not

finger start, chase threads on a

drill press, using a tap aligning

tool and frame levelling block.

See fig. 59.


Check Early Style Crane- Frame Fit

Checking correct crane/frame fit is the

first reassembly step. See figure 60.

1. Install the crane, crane lock

detent, and lock screw. Then, snug the lock screw.

2. Check endplay with crane open.

Then, close the crane, taking up

slack with slight forward

pressure. On closing, the crane

flange should brush the back of

the frame, but not hit the corner.

See fig 61.

3. Check the crane guide for nicks,

dents, or drag marks. Lightly

dress high spots until drag is gone. Don't undersize.

4. Check the front crane-to- frame

joint. The crane should close

easily, without applying pressure,

and rest against the frame with a

hairline fit.

5. If fit is questionable, see crane

alignment, Section II.

About Crane-Open Endplay and

Early Style Cranes

A small amount of open crane endplay

is normal and necessary in all early

style D, E and I model cranes.

1. If the crane flange slides by the

frame without striking or

indenting the flange as the crane

closes, open crane endplay is not

excessive.

2. Refitting is necessary if the crane

barrel flange hits on closing; is already dented or marked from

previous frame strikes; if wear is

present at the crane stem's detent

engagement face, at the crane

lock detent tip, or at both. See

figs. 61, 62, 63.

3. After fitting, level any raised

material at the strike marks on the

flange- but do not bevel, thin, or

undersize the crane flange, or

frame.

Figure 60- Shows early crane/frame fit check points. On

closing, the flange at "A" should lightly contact the inside of

the frame, but not hit or drag. At "B", the bottom of the crane

should clear the crane guide without contact or drag. The crane

arm at "C" must close easily and fit 100% against the frame

without a gap.

Figure 61- Shows excess open crane endplay in an early style

crane. This is caused by crane stem detent engagement surface

wear and/or wear on the detent itself, and allows the crane

barrel flange to hit the corner of the frame as the cylinder

closes. Inset illustration at bottom shows wear points that cause

this problem.


Figure 62- Shows an early style crane stem positioned on a

bench block, ready for peening and tightening of the stem's

detent engagement surface. An aluminium pad is placed under

the stem to prevent flattening on the back side. Peen only that

part of the stem that contacts the detent tip as the cylinder is closed.

Figure 63- Illustrates closed crane endplay at the crane/frame

bearing junction. When wear exists here, re-fitting the detent or

crane stem pulls the crane flange back, away from the frame,

leaving the crane flange unsupported. This also closes

headspace. Insert a .002, .003, or .004" bearing washer to

compensate for wear.

Fit Early Style Crane Stem Detent

Engagement

The only part of the stem's detent

engagement wall that is tightened in

peening is the approximate 1/4 that

lines up with the crane lock detent tip when the crane is opened and closed.

See figure 62. The best tool for this

job is a 6 oz. ball peen hammer, with a

perfectly smooth, flat face.

1. Peen the edge of the stem's detent

engagement wall using light to

medium taps only. Don't round

off or indent the corner of the

detent engagement wall, since

crane lock detent tip overlap only runs about .035 to .040".

2. An alternate method is to TIG

weld and build up the detent

engagement tip and then refit it to

the crane slot.

About Closed Crane Endplay In

Early Style Cranes-

Loose, worn cranes will allow closed

crane endplay. If loose enough,

[particularly with a very weak latch spring] the ratchet will drag and/or

strike the edge of the frame when the

cylinder is closed. When crane/frame

bearing junction wear exists, peening

and refitting the crane stem pulls the

crane flange back and leaves it

unsupported. Headspace is also

affected. Replacing worn, early cranes

is difficult with early parts

unavailable. To replace worn material,

a useful alternative is to install a stainless steel bearing washer at the

crane- frame bearing junction. This

repositions the crane flange on the

frame and allows the cylinder to

correctly headspace on the flange.

See fig. 63 and section on headspace.


Check Late Style Crane- Frame Fit

1. Install late style crane, and check

stem fit inside the frame. Then, install

the crane lock detent, spring, and

crane lock screw. Snug the screw.

2. Then, check for correct spring pressure. The lock detent spring must

exert only enough pressure to maintain

positive crane position. To eliminate

detent spring bind, shorten the spring

one turn.

3. If crane hinges loosely, replace

spring and/or detent.

4. Check that the front of the crane

barrel just clears the frame on closing.

5. Inspect closed crane for a hairline

crane/frame joint. If fit is questionable, see crane alignment,

Section II.

About Late Cranes & Locks-

The late style crane lock design update

first appeared in production revolvers

near the end of WWII. By simply

locating the crane stem's bevelled

plunger slot slightly forward, the

spring loaded crane lock detent

plunger easily maintains a positive pressure on the stem, keeping it drawn

back against the frame bearing. This

system eliminates crane endplay. With

the late style cylinder update of 1976,

the crane barrel flange was eliminated,

allowing the new style longer cylinder

collars to headspace directly on the

frame. This unloaded the crane,

freeing it to act only as a pivot. Except

for realignment of bent or sprung

cranes, these basic changes have virtually eliminated all crane related

field service problems.

Figure 64- Shows a close view of a late style crane and frame.

Notice, at "A", that the crane barrel flange has been factory

eliminated so that the cylinder collar can now headspace

directly on the frame. At "B" the old style crane guide has been

set back into the frame to provide room for a wider, stronger

crane arm.

Figure 65- Illustration shows a late style crane, crane lock

detent, spring, lock screw and frame in half and cross-sectional

views. Placement of the bevelled crane stem slot, in this

excellent design, is slightly forward of the detent tunnel in the

frame, enabling the detent plunger to hold constant back

pressure on the crane stem.


Figure 66- Shows a sprung crane with a crane- to-frame joint

gap at "A". Cylinder impact bent this crane inward. It no longer

fits the frame correctly. The arrow at "B" indicates bend

direction. The back of the crane barrel, in this classic and

extreme misalignment example, is to the right when the revolver is held down-range.

Figure 67- Shows a crane with a thimble gauge installed and

ready for the crane alignment check. When the crane is

straight, the thimble gauge tip easily drops into the latch pin

tunnel just as the crane is closed. This test positively

determines whether the crane is straight and in agreement with

frame and latch pin centreline.

Check Crane Alignment

With other crane work done, the next

step is to check crane alignment.

Although most of the cranes you

check will be straight, a number won't

be- and for that reason all cranes must

be checked. See figures 66 and 67. Including the example shown, there

are four basic bend directions. Bent or

sprung cranes may or may not show a

gap at the front, since both the

direction and amount of bend will

vary in each case.

Gauge Check Alignment

Crane alignment is probably very

close, or correct, if, during the before disassembly pre-check, the cylinder

latch easily engaged the ratchet in all

six chamber positions under latch

spring pressure alone, without

resistance and/or the need to push on

the cylinder.

The thimble alignment gauge test is

simple and positive. See figure 67.

With this method, the exact position of

the gauge tip in relation to the latch

pin tunnel can be seen as the crane

closes. Two gauges are needed: one for E/I models, and a second for

smaller D model cranes. Check

alignment as follows:

1. Install the thimble gauge on the

crane barrel.

2. Place the revolver on the bench,

pointed straight up.

3. Close the crane. The thimble

gauge tip should drop in to the

latch pin tunnel with the crane closed.

4. In cases where the gauge tip won't

drop in unless the crane is pushed,

the crane is sprung. See crane

alignment in Section II.


About service procedures and Colt D, E, and I model cylinders-

Service procedures are based on experience and developed for checking, refitting, and/or replacement of

parts or parts assemblies. Tolerances, working clearances, wear limits, and etc., are determined by

blueprint. Heat treating to design specification determines the working toughness or hardness of the basic

steels used. From there on, wear, abnormal wear, and/or abuse take over. These factors have everything to

do with how cylinders are inspected and function checked. With this in mind, most of the reasons behind service procedures with Colt cylinders are easy to see when the manufacturing steps are known.

Late style Colt revolver cylinders are manufactured as follows:

1. The cylinder body is fully machined, but with chambers reamed only to the semi-finished stage.

2. The internal spline guide insert is machined and pressed into the back of the cylinder.

3. Ejector star/ratchet guide pins are pressed in and end chamfered.

4. The ejector stem and ejector ratchet are assembled and staked.

5. The ejector/ratchet/stem assembly is installed, aligned, and fit on the cylinder's guide pins.

6. The chambers are finish reamed with the ejector star in final seated position. This mates the ejector

star fingers with the cylinder. 7. Both ratchet shoulder height and cylinder collar length are left oversize for final fitting into either a

new production frame, or for later parts use as a replacement cylinder assembly.

8. The completed cylinder assembly is then finally heat treated to blueprint specification as a unit. The

assembly is then finished.

For these manufacturing related reasons, cylinder guide pins and late ejector star/ratchet/stem assemblies

are factory replacement only. Factory service procedure requires that cylinders needing this work be sent

back through the cylinder manufacturing line before refitting in the service department.

Correct service procedures require cylinder replacement when any of the following conditions are

found:

1. The cylinder collar is beyond reasonable stretch limits.

2. The internal spline guide is altered or damaged.

3. Bolt slot cuts are worn, altered, buffed out, or damaged.

4. The front or rear of the cylinder is altered or damaged.

5. Chamber or overall cylinder condition is not acceptable.

6. Exterior/interior rust pitting is present.

For liability reasons, field service procedures should be no less strict.


Figure 68- Shows checking cylinder bolt slot cuts by using the

cylinder bolt as a gauge. In making this check, be sure the bolt

is correctly aligned. The bolt must drop into each slot without

resistance. There should be virtually no sideplay with the bolt

engaged. Nicks, and slot damage, can interfere with bolt

engagement.

Figure 69- Shows early and late style ejector star guide pin

locations. Early pins position just at the tips of the ejector star

fingers. Late bevel-head pins are placed closer to the centre of

the cylinder. If nicked or tip burred, late style pins can be re-

chamfered with a guide pin dressing tool. Tool is shown

separately, at right.

Check Cylinder Bolt Slots

Bolt slot cuts must be detail checked

before the cylinder can be used. See

figure 68. Worn, loose, and/or altered

bolt slots may allow locked cylinder

misalignment. Slot corners that are over polished or "pulled-out" on a

buffer, may not have enough surface

area left for positive bolt lockup.

Nicked, dented, or otherwise edge

damaged bolt slots can interfere with,

and in some cases prevent, full

cylinder bolt engagement.

1. Check slot cuts using the original

bolt head as a gauge.

2. Slots are acceptable if there is no bind or sideplay.

3. If the slot engagement is loose

with the original bolt, recheck

with a new cylinder bolt. If the

new bolt solves the problem, tag

the part for replacement on

reassembly.

4. When slot fit is still loose, replace

the cylinder. Note: Don't attempt

peening or tightening cylinder

slots- alignment can be affected.

5. Lightly nicked cylinder bolt slots can be carefully dressed with a

fine pattern file or a thin flex

stone strip.

6. Always check slot size against the

bolt head when dressing. Don't

oversize.

Check Ejector Guide Pins

1. There are two ejector star guide

pins. Though seldom loose or missing, make sure both are in

place. See fig. 69.

2. Nicked or dented pins can be

dressed providing ejector fit is

correct and the fingers don't

overlap the chambers.

3. Replacement guide pins are not

factory listed. If loose or missing,

they can be made from std. pin

stock.


Check Early and Late Style

Ejector/Ratchets

After cylinder body checks have been

completed, and the guide pins

checked, aligned, dressed, or replaced,

etc., the ejector/ratchet is then ready for close inspection, fit check, and

detailing.

1. Check the latch pin recess inside

the ratchet. The latch pin should

bottom without resistance and fit

with no more than about .001"

play.

2. If fit is looser, recheck with a new

latch pin.

3. Inspect ratchet lugs, guide pin recesses, and ejector star, and

lightly deburr as needed. See

figure 70.

4. Check stem tightness with late

style ejector/ratchet assemblies. If

loose, re-stake the thread joint

with a prick punch. Early style

ratchets are staked after the

cylinder is assembled. Never

reuse misfit, altered, or damaged

ejector/ratchets. With early style

cylinders, [subject to parts availability] replace the ratchet.

With late style cylinders, send the

cylinder to factory service for

ratchet and stem replacement and

refitting to the cylinder.

Check Ejector Star Fit in Cylinder's

Ejector Recess

1. Drop the ejector/ratchet into its

cylinder recess and check fit. See figure 71.

2. If ejector star finger tips bind,

lightly dress tips and cylinder

contact areas.

3. Make sure the star slips easily

over the guide pins, and self-

aligns as it bottoms. At rest, the

top of the ejector star should be at

flush with, or just slightly below,

the level of the cylinder.

Figure 70- Shows close views of both sides of an early E frame

ejector/ratchet, at top. A late I frame ejector/ratchet and stem is

shown just below. Detail points are indicated. Pin recesses at

"A" may need deburring. Inside corners of star fingers at "B"

may require chamfering. Ratchet edges at "C" may need light de-burring.

Figure 71- Shows two views of a late style D frame

ejector/ratchet being fit checked inside its parent cylinder.

When ejector guide pins are straight, ejector pin recesses de-

burred, and ejector star finger tips correctly end chamfered, the

star should easily bottom in the cylinder's receiving recess just

at, or slightly below, flush.


Figure 72- Shows ejector star sideplay check in a Tate style

cylinder. There is no specification for ejector sideplay- but it

should be little, and not enough to allow ejector star fingers to

overlap into chambers. In early cylinders, it should be near

zero. A finishing reamer or burnishing tool is used to remove

any extra finger material.

Figure 73- Shows a ceramic burnisher used to adjust ejector

star roughness left from previous ejector fitting and/or overlap

caused by ejector sideplay. Full size dummy rounds, or fired

cases, are inserted in every other chamber to position the star

fingers. Chambers are then burnished in rotation until there is

no overlap.

Check Ejector Star Sideplay and

Overlap

When ejector/ratchet detail work has

been finished, and the ejector star

smoothly and positively self aligns

and bottoms in the cylinder, both ejector star sideplay on the guide pins,

and star finger overlap can be

checked. Early pinned tip ejectors

were originally factory fit to zero

sideplay and overlap. Unless pins

are missing, the ejector is damaged,

or a replacement has been misfit, it

probably won't require more than an

inspection. However, late style

ejectors are clearance fit to self align

on chamfered guide pins. This design requires only a small amount of

sideplay to work correctly. See fig. 72.

Star fingers must be adjusted to agree

with inside chamber walls when they

are found to overlap into chambers or

are rough from some previous

ejector/ratchet replacement.

Adjust Extractor Overlap and

Burnish Chamber Walls

Overlapping and/or rough extractor star fingers, and chambers with

machine lines inside, possibly left by a

dull reamer, may require a finish

reaming step before final inside

polishing with a ceramic

burnishing tool. Small amounts of

overlap and light chamber machine

lines can be eliminated at the same

time by burnishing. See fig. 73.

Chamber burnishing can also improve

case extraction. The best procedure is to rotate the burnisher while

moving it in and out, much like using

a cylinder hone.


Check Early and Late Style Ejector

Rod and Stem

Before cylinder reassembly, early and

late ejector rods must be runout

checked, then straightened and dressed

as needed. The ejector rod and spring in older revolvers are usually found to

be heavily gummed or varnish coated.

Detail clean ejector rods and springs

before checking. In late style

cylinders, the ejector rod bushing

collar picks up the ejector spring and

supplies ejector return pressure. See

figure 74.

1. Check ejector spring end crimp.

The end of the spring must fit into the rod flange slot, or on the late

bushing collar, tightly enough so

that the spring can't slip over the

rod flange or bushing rim.

2. Inspect, deburr threads, clean rod

with a brass brush.

3. Check ejector stem spline, or

splines. Lightly dress any nicks or

burrs found at spline corners. Do

not undersize.

4. If stem or splines have been

altered or damaged, replace ejector rod, or stem.

Check Ejector Rod Runout

Early and late ejector rods bend just at

the point the rod enters the crane.

While Colt ejector rod design is more

forgiving than rods in most other

revolvers, bent ejector rods can stick,

make ejection hard, and in extreme

cases, even interfere with opening and closing the cylinder. Ejector rod

runout is easily checked using either

method shown in figure 75.

Rods with compound or Zee- bends

are pre-straightened on a bench block.

See fig. 76.

Figure 74- Shows check points for early and late ejector rod

assemblies. The ejector spring crimping point is shown, above.

Rod threads, spline slots, spline edges, and rod runout, or bend,

should be checked. The typical rod bend point is indicated

below. With late cylinders, make sure the ejector rod bushing is installed.

Figure 75- Shows two basic ejector rod runout checking

methods. The lathe and dial indicator method at "A" is fastest,

and most accurate, for both rod checking and straightening.

The drill press and reference point method at "B" is slow, but

as accurate as drill press bearings will allow. Rods that are

"Zee-bent" will require peening.


Figure 76- Shows an early style ejector rod being peened and

pre-straightened. Best tools for this job are an 8 oz. brass

hammer and a steel bench block. Care should be taken not to

further stretch the rod. Rotate and lightly tap high spots until

the hump or Zee bend is gone. Finish straightening on a lathe or drill press.

Figure 77- Shows hand spin polishing the outer surface of an

ejector rod stem with #600 sand cloth. Only high spots and

sharp edges are dressed. Stem fit is then tested by temporarily

installing cylinder, stem, and rod on the crane, and then

checking for any remaining drag with the stem in actual

operating position.

Peen/Straighten Ejector Rod

Generally, most bent ejector rods are

only slightly bent and are easily

straightened.

1. Chuck late style ejector rod, or early style rod stem. Rotate and

check the end against a dial

indicator or reference point. See

fig. 75.

2. Hand adjust the rod as indicated.

Then, recheck runout. Adjust as

necessary, until the rod runs true.

3. Rods that are severely bent are

stretched on one side. Those that

have been field straightened tend

to stretch again, and form a hump, compounded bend, or Zee in the

rod. Further attempts to hand

straighten will likely ruin these

rods.

4. The best straightening procedure

with stretched rods is to rotate and

tap the rod until the hump, or Zee

is level. Finish straightening on a

lathe or drill press. This helps to

minimize work hardening. See

fig. 76.

Polish Ejector Rod Stem

1. Lightly polish rough stem edges

and high spots with #600

sandcloth. See fig. 77.

2. Check late ejector stems by

placing the cylinder on the crane,

slipping in the ejector stem, and

twisting in the front part of the

rod.

3. Then, function check for any remaining ejector stem drag.

Lightly re-polish the stem as

needed.

4. Pre-assemble early style one piece

ejector rods and cylinders, and

make a similar function check.

5. With fitting completed, the crane

and cylinder are ready for

reassembly. See figures 78

through 83.


Figure 78- Shows early style crane/cylinder reassembly sequence: A. With early style one piece ejector

rods, the crimped end of the ejector spring is positioned in the rod flange slot, against the raised flange in

the middle of the rod. Caution: a loose fit may allow the end of the spring to slip over the flange, resulting

in a loss of return spring pressure and, in some cases, may also bind the ejector. B. The ejector rod and

spring are then installed in the crane. C. The crane bushing is hand started before screwing it in with the

bushing wrench. D. The cylinder is installed on the crane barrel. E. The ejector ratchet is carefully hand

started on the ejector rod threads. See figures 80 and 81 for ratchet aligning and tightening. F. The ejector

rod head is threaded on to just finger tight- plus about l/8th turn. Do not overtighten.

Figure 79- Shows late style crane/cylinder reassembly sequence: A. The smaller, tighter end of the ejector

spring is slipped onto the ejector rod bushing collar. Note: If spring fit is not snug enough on the collar,

lightly crimp the last coil to

prevent the end of the spring from slipping over the top of the bushing collar flange. B. The ejector rod bushing and spring are positioned inside the crane. C. The crane bushing is hand started before screwing

it in with the bushing wrench. D. The cylinder is installed on the crane barrel. E. The ratchet/stem

assembly is then inserted in the cylinder. F. The ejector rod is threaded in to finger tight, plus about l/8th

turn. Caution: When tightening rods in late style cylinders, install full size dummy rounds or fired shell

casings in every other chamber to help support the single ejector stem spline. Do not overtighten.


Figure 80- Shows a ratchet wrench being used to tighten an

early style ejector/ratchet. Being progressive, as well as factory

staked, ejector rod threads tighten as the ratchet is rotated on. If

ratchet is loose from previous unthreadings, see figure 82.

Don't twist the ejector star past the correct alignment point, as

shown in fig. 81.

Figure 81- Shows a close view of an early style ejector/ratchet

as it is being carefully fine adjusted to exact alignment with the

cylinder's ejector guide pins. The tip slots at the ends of the

ejector star fingers must correctly centre over the guide pins to

prevent star finger drag, or bind, as the ejector is cycled and

lowered.

Re-torque Early Style

Ejector/Ratchet

Once the crane and cylinder are fully

assembled, and the ejector has been

hand started and threaded to finger

tight, the ejector/ratchet can then be tightened and aligned.

1. Secure the cylinder body between

aluminium vice jaws, or in a

clamping fixture. See figure 80.

2. Push the ejector rod up and hold it

just high enough to allow the

ejector star fingers to clear the

cylinder.

3. Install the correct D, or E/I model

ratchet wrench. Carefully tighten the ratchet until only about 1/8

rotation remains. See figure 81.

4. Final rotate the ratchet, slowly,

just a bit at a time. Closely watch

the rod staking marks inside the

latch pin recess, the ejector guide

pins, and the tip slots at the edges

of the star fingers.

5. Stop at the exact point that the

star finger tip slots line up

perfectly with the cylinder's

ejector guide pins. See figure 81.

Note: Just at, or before, the correct

ejector star alignment point, the

ejector/ratchet should be reasonably

tight on the ejector rod's threads. If

not, re-staking may be required. See

figure 82. When rod threads are still

loose after re-staking, the ejector rod

must be replaced. Caution: Rotating

the ejector star past the alignment

point can flare and/or compression damage the rod shoulder and stretch

damage the threads, as well. This is

one of the major causes of rod

damage.


Re-stake Loose Ratchet-Rod Thread

Junction

Early style ejector rod and

ejector/ratchet threads can loosen

slightly with initial removal and re-

installation. Generally, loosening increases with later removal. Late type

ejector/ratchets are not made to be

field removed, and will rarely loosen

by themselves. Since the ejector star

must positively self-align with the

cylinder on closing, re-staking the

thread junction becomes necessary if

the ratchet is no longer tight at exact

alignment with the guide pins in the

cylinder. See figure 82. Unless the

ratchet has been grossly over twisted during a previous replacement, inside

threads are seldom damaged. Careless

over-twisting usually compresses the

ejector rod shoulder while also

stretching the rod threads. When this

is done, the ratchet can't be reliably

staked. Replace any ejector rod in this

condition. Caution: A certain amount

of material is always flared and raised

in the staking process. Since it's

possible that full entry of the cylinder

latch pin could be limited, flared areas must be levelled. Face reamers for

dressing the bottoms of staked D and

E/I ratchet latch pin recesses in either

a mill or drill press are very easily

made by slightly modifying std. 3/16"

and 1/4" end mill bits. Undersize and

dull the O.D. of the last 1/4" of an end

mill bit, to provide safe, no-cut

clearance while inside the latch pin

recess. Warning: Do not lower depth

or enlarge inside diameter of the latch pin recess.

Figure 82- Shows re-staking the ratchet-ejector rod thread

junction with a staking punch. Prick punches can be used, as

well. Ratchets are best secured by lightly staking at four points-

this also raises minimum material at the bottom of the latch

recess. Bench blocks with centre relief holes provide rod and

cylinder collar clearance.

Figure 83- Shows two views of ejectors being rechecked after

final assembly and/or re-staking work. At "A", the ejector is

closely inspected to make sure that it easily self aligns over the

guide pins and that the star fingers bottom just at, or slightly

below flush. At "B", the stem is rechecked for drag free travel

in the cylinder.


About Headspace, Cylinder Endplay, and Barrel/Cylinder Clearance

Keep in mind that here we are discussing only Colt's D, E, and I frame double action revolvers- and not

other models, brands, or types. And, there are specification differences, as well, between D, E, and I

frame revolvers. See the "Headspace and Clearance Table" on the next page for currently available

factory specifications and data on various model and calibre variations.

Headspace- is set at the factory by face-milling the cylinder collar to a finished length that just allows

entry of a minimum specification headspace gauge between the back of the cylinder and the frame, or

with D and E models, where the recoil plate is pressed into the frame. For example, Python model factory

minimum headspace specification is .062", and maximum headspace is .070". Setting headspace to the

.062" minimum, rather than toward maximum, is naturally safer, and allows for some amount of normal

seating, wear, and possible later cylinder endplay adjustment.

Cylinder Endplay- after cylinder collar length and headspace are established, endplay is set by surface

grinding ratchet shoulder length to the point that the cylinder assembly just fits in the frame. Fitting the

ratchet in this way leaves minimum cylinder endplay with the cylinder closed. With this fitting method,

the cylinder is "spaced" in the frame by the finished shoulder of the cylinder collar, at front, and the finished ratchet shoulder, at the rear. Any room left over is endplay. Historically, almost all of the new D,

E, and I frame revolvers that I have examined appear to have left the factory with .001", or less, in-frame

cylinder endplay. Maximum cylinder endplay specified for D, E, and I frame revolvers is .003". See

"Headspace and Clearance Table".

Barrel/Cylinder Clearance- after the cylinder collar and ratchet shoulders have been fit, final

barrel/cylinder gap is set by adjusting the finished length of the rear barrel face to the correct cylinder

clearance. Most standard, factory new D, E, and I revolver barrel/cylinder clearances I have checked

measure between .004" and .006". Factory minimum barrel/cylinder clearance specification is .003" for

these models. Factory maximum clearance specification for all D, E, and I frame models is .008".

Once factory set, anything that causes or allows cylinder movement beyond original specifications creates some amount of cylinder endplay, and changes both headspace and barrel/cylinder clearance, as

well. Specifically, any of the following will affect the three-way clearance-tolerance relationship between

the barrel, frame, and cylinder:

1. Normal wear or seating, and frame/cylinder collar/ratchet polishing

2. Frame stretching and/or ratchet peening [high and overpressure loads]

3. Cylinder collar compression [high and overpressure loads]

4. Cylinder substitution, miss-fitting, altering/undersizing the cylinder collar

5. Ratchet substitution, mis-fitting, altering/undersizing the ratchet shoulder

6. Mis-fitting the rear barrel face and/or cylinder alterations

Also see figures 84 through 88, and cylinder replacement in Section II.


Headspace and Clearance Table- D, E and I Frame Revolvers 71

Frame Calibre Model Headspace Endplay Barrel Clearance

Size Min. Max Max. Min. Max.

D .22 LR Police Positive .043- .048" .003" .003- .008"

D .32 NP Police Positive .055- .062" .003" .003- .008"

D .38 SW Police Positive N.A. .003 .003- .008"

D .38 CS Police Positive N.A. .003" .003- .008"

D .32 NP Police Pos. Spl. .055- .062" .003" .003- .008"

D .32-20 Police Pos. Spl. N.A. .003" .003- .008"

D .38 C Police Pos. Spl. N.A. .003" .003- .008"

D .38 Spl Police Pos. Spl. .060- .065" .003" .003- .008"

D .38 Spl Border Patrol .060- .065 .003" .003- .008"

D .22 LR Banker's Special N.A. .003" .003- .008"

D .38 CS Banker's Special N.A. .003" .003- .008"

D .38 SW Banker's Special N.A. .003" .003- .008"

D .38 Spl Detective Spl. .060- .065" .003" .003- .008"

D .38 Spl Commando Spl. .060- .065" .003" .003- .008"

D .22 LR Cobra .043- .048" .003" .003- .008"

D .32 NP Cobra .055- .062" .003" .003- .008"

D .38 Spl Cobra .060- .065" .003" .003- .008"

D .22 LR Courier .043- .048" .003" .003- .008"

D .32 NP Courier .055- .062" .003" .003- .008"

D .38 Spl Courier .060- .065" .003" .003- .008"

D .38 Spl Agent [early] .060- .065" .003" .003- .008"

D .38 Spl Agent [Late] .060- .065" .003" .003- .008"

D .38 Spl Viper .060- .065" .003" .003- .008"

D .22 LR Diamondback .043- .048" .003" .003- .008"

D .38 Spl Diamondback .060- .065" .003" .003- .008"

E .32-20 Army Special N.A. .003" .003- .008"

E .38 C Army Special N.A. .003" .003- .008"

E .38 Spl Army Special .060- .065"* .003" .003- .008"

E .41 C Army Special N.A. .003" .003- .008"

E .22 LR Official Police N.A. .003" .003- .008"

E .38 Spl Official Police .060- .065"* .003" .003- .008"

E .38 Spl Commando [WWII] .060- .065"* .003" .003- .008"

E .38 Spl Marshall .060- .065"* .003" .003- .008"

E .38 Spl Officer's Model .060- .065"* .003" .003- .008"

E .38 Spl Officer's Special .060- .065"* .003 .003- .008"

E .22 LR O.M. Target N.A. .003" .003- .008"

E .38 Spl O.M. Target .060- .065"* .003" .003- .008"

I .357 M .357 Magnum .062- .070" .003" .003- .008"

I .22 LR Trooper [Orig] N.A. .003" .003- .008"

I .38 Spl Trooper [Orig] .062- .070" .003" .003- .008"

I .357 M Trooper [Orig] .062- .070" .003" .003- .008"

I .38 Spl Python .062- .070" .003" .003- .008"

I .357 M Python .062- .070" .003" .003- .008"

The above models/frames have been manufactured in more chamberings than shown, but the vast majority of production has been in the standard chamberings listed above.

The "D" frame designation was adopted in 1947 and is also used here to identify similar models made on the same basic frame manufactured before 1947.

The "E" frame designation was first adopted during manufacture of the Official Police model, and is used

here to identify medium frame revolvers originating before I designated models.

.41 C = .41 Colt, .38 C = .38 Colt, .38 CS = .38 Colt Short, .32 NP = .32 New Police/.32S&W Long

Some factory armourer data sheets show intermediate .38 Spl. E frame model maximum headspace specification changed to .068" max. However, I suggest staying with the original, more conservative

.065" limit.

N.A.= Headspace data not available from the factory at the time of printing.

Where headspace safety data is not available for earlier revolvers- centerfire cartridge minimum headspace can be roughly estimated at factory shell head thickness dimension plus .005- .006" maximum,

as an allowance for shell head clearance. "No-go", or max. headspace, in most centerfire revolvers,

averages .004- .005" over minimum headspace. (This data is for reference only- not a specification.)

If there is any headspace or safety question about any older Colt revolver- don't fire it, send it to factory service for inspection.


Half-sectional illustrations show D and I model measuring points for headspace and barrel clearance gap.

-Drawings courtesy Colt Industries, Firearms Division


Most cylinder headspace-endplay problems are caused by frame stretching. Stretching, in turn, results

from use of over pressure loads and/or continuous use of heavy loads. Increased headspace and endplay,

in some cases, are purely the result of mis-fitting. Also see figures 49 and 49A.

Illustrations are exaggerated for example

Figure 84- Illustration demonstrates the basic three-way clearance-tolerance relationship between cylinder headspace, cylinder in-frame endplay, and the barrel/cylinder clearance gap, in Colt D, E, and I frames.

Anything done with the cylinder collar or ratchet shoulder that changes one of the above clearances

always affects the others. Frame stretching and ratchet seat damage also affect all three.

1A. When headspace is excessive [open]- the back of the cylinder is too far from the frame. On firing,

cases push back to the extent that they may not be well supported. Risk potential for case splitting,

ruptures, etc. is increased.

1B. When headspace is too little [closed]- the back of the cylinder is too close to the frame. Shell heads

may drag and bind the action. With closed headspace, an otherwise normal firing pin protrusion can

puncture primers. Particularly under magnum firing pressures, primer jackets may flow back into the firing pin port and drag, stiffen, or stop the next cylinder rotation. Primer jacket material can jam the

action, or make the action feel rough.

2A. When cylinder endplay is excessive- both headspace and barrel/cylinder clearance are affected. The

cylinder moves forward on firing, opening headspace and decreasing barrel/cylinder clearance. In

extreme cases, the front of the cylinder can strike the rear barrel face.

2B. When cylinder endplay is too little- not enough cylinder-frame clearance exists. The cylinder can

drag on opening and closing. Low clearance may also cause the ratchet to strike the frame on closing. For

match accuracy, near zero clearance is desirable, providing the cylinder opens and closes easily. For

service duty use, about .001" endplay is considered optimum.

3A. When barrel/cylinder clearance gap is too great- the large gap allows excess pressure drop, heavy

powder flash, particle spitting, and etc. Performance is adversely affected. Undersized ratchet shoulders,

cylinder endplay, incorrect trimming of the rear barrel face, and stretched frames all increase

barrel/cylinder in-frame clearance.

3B. When barrel/cylinder clearance gap is too small- lead and/or firing residue build-up on the front of

the cylinder and at the barrel face can cause cylinder drag or bind. In worst cases, on rotation, the cylinder

drags the barrel.


Figure 85- Shows an early style cylinder in the frame, ready for

headspace gauge checking. The crane is straight, the crane

barrel flange fits tight to the frame, and the cylinder collar is

de-burred and clean. The recoil plate has been checked for

nicks, dents, and raised areas. Flaring at the firing pin port has

been levelled.

Figure 86- Shows gauge checking cylinder head space in an I

frame revolver. The revolver is held muzzle down with the

cylinder collar tight to the frame- this would be tight to the

crane flange with old style revolvers. Gauge width must be

narrow enough to keep the insert from binding between the

frame and ratchet edge.

Gauge Check Headspace

Headspace in most revolvers crossing

the revolversmith's bench will

measure within factory specification.

Only a small number will not gauge

correctly. But, for that reason, all cylinders must be carefully headspace

checked. Check headspace even if the

revolver has less than .003" endplay,

since low endplay gives only an

estimate of overall condition. The fact

is, without headspace gauge checking,

you can't tell what cylinder conditions

really exist in the revolver. It can't be

done by feel or by eye.

1. Check "Headspace and Clearance Table" for correct model and

calibre headspace.

2. To prevent false gauge

measurements, always pre-check

both crane and frame condition.

See figure 85.

3. Position and gauge check cylinder

as shown in fig. 86.

4. Minimum headspace must not be

under specification for model and

calibre. The correct minimum

gauge must enter the space between the frame and the rear of

the cylinder. Clearances of .001"-

.003" beyond minimum

headspace are not unusual in well

used revolvers.

5. Recheck the revolver with a

maximum headspace gauge. The

gauge must not enter. The

difference between max. and min.

headspace is usually about .005".

See "Headspace and Clearance Table".

Note: Most revolvers easily pass

headspace gauge tests. If one does not,

make checks in figs. 87 and 88 and see

cylinder work in Section II.


Barrel/Cylinder Clearance

When the cylinder has passed the

headspace check, the next step is to

check maximum and minimum gap

size, or clearance, between the front of

the cylinder and the back of the barrel. See figures 87 & 88. Most current

standard production revolvers leave

the factory with clearances somewhere

between .004" and .006". Normal

wear-in and seating will change this

clearance, somewhat.

1. Hold the cylinder back, insert

feeler gauge and check the gap.

Clearance must not exceed the

maximum limit of .008". See Clearance Table.

2. Then, holding cylinder forward,

again measure gap. Clearance

must not be less than specified

minimum of .003". See Clearance

Table.

About Cylinder Endplay-

To determine the amount of cylinder

endplay that is actually present, deduct

the minimum gap measurement from the maximum gap. Generally

speaking, with cylinder headspace

factory set just at minimum, and

barrel/cylinder clearance at .006", an

endplay increase of .002" would take

barrel/ cylinder clearance just to the

specified .008" maximum. If the .002"

increased endplay is caused by frame

stretch, and both the cylinder collar

and ratchet are still as factory fit- the

.002" will show as increased headspace when the cylinder collar is

against the front of the frame. For

more cylinder data, see Section II.

Figure 87- Shows measuring maximum barrel to cylinder

clearance with a standard feeler gauge. The cylinder is held

back with the ratchet hard against the ratchet seat. The

maximum factory specified clearance for all Colt D, E, and I

frame revolvers is .008". Insert the gauge from both sides to

check evenness of rear barrel face.

Figure 88- Shows measuring minimum barrel to cylinder

clearance, also using a standard feeler gauge. In this check, the

cylinder collar is held forward against the frame; in early

revolvers, against the crane barrel flange. Subtract minimum

from maximum clearance to find the existing amount of

endplay in the revolver.


Figure 89- Shows both E/I & D cylinder bolts, springs, and bolt

pivot screws. All indicated points must be checked for wear,

mis-fitting, or alteration. Bolt springs and pivot screws must be

correct and in good condition. Comparing all three parts to new

factory replacements gives a fast reference- and is a

worthwhile first step.

Figure 90- Shows important E/I cylinder bolt head fitting

points. The bolt head should match the contour of the bolt slot

leads milled in the cylinder. Bolt head side bevel is about

.008"- .010". Head profile is slightly curved, placing the

cylinder contact, or riding point, 2/3 to 3/4 of the way down on

the lower side of the head.

Inspect D, E/I Cylinder Bolt

After cylinder/frame checks are

complete, return cylinder assembly to

the parts box. Bolt timing was very

likely close if the cylinder locked and

unlocked properly at the initial pre-check. But just the same it's a good

idea to make sure the bolt is 100%

correct. Check as follows:

1. Detail inspect the bolt head, stop

shoulder, and bolt actuator tip for

signs of excess wear, alteration,

or mis-fitting. See figure 89.

2. Check bolt spring length and

condition. Part numbers are: D-

50381 & E/I- 50435. 3. Closely check pivot screw slot,

threads, and shoulder.

4. Comparison check the bolt,

spring, and screw against new

Colt replacement parts. Replace

any item that shows signs of

excess wear, mis-fitting, and/or

alteration.

Fitting the E/I Bolt Head

When cylinders have more than the usually very slight "bolt riding line"

around the outside [from normal

closing and rotating against a raised

bolt], typically, the top point of the

cylinder bolt will be found riding, and

gouging, the cylinder. With the correct

riding point on the lower side of the

bolt, it will follow rather than gouge.

1. Check bolt head contour.

2. Dress head contour to fit cylinder slot leads.

3. Check both bolt head side bevel

and head profile. Curve profile for

proper cylinder riding point

position.

4. Final polish head bevel with #600

sand cloth. Lightly break sharp

corners at high and low head

points.


Fitting the D Bolt Head

Fitting the D frame bolt head is a bit

more critical due to the D cylinder's

narrower bolt slot cuts and the D bolt's

correspondingly smaller bolt head.

Smaller D head size makes a cylinder riding point closer to the lower bolt

edge necessary. When fitting and

polishing this bolt head, extra care is

needed. Rounding off or over curving

the lower bolt corner can allow the

cylinder to back-roll to the left, or lead

side, and off the bolt head. While the

tendency to back-roll is overcome by

the hand when the hammer is cocked

in either the single or double action

mode, back- roll is an incorrect condition and is evidence of either

excess wear or poor fitting. If the bolt

head is not excessively worn or

rounded off, head engagement can be

improved by raising the top of the bolt

and refitting the head. See figure 100.

Check Bolt Head Top Corner and

Cylinder Riding Point

If the angle at the top of the bolt

causes the top corner of the bolt head, or top point, to contact or ride on the

cylinder or gouge the bolt slot leads, it

should be polished and slightly curved

until the point just clears the cylinder.

With D bolts, this slight crowning

effect moves cylinder contact to the

other side of the bolt head. Hand

check for top point clearance by

sliding the bolt down the leads and

into the cylinder's bolt slot cuts. With

the bolt installed, the top point must just clear the cylinder at all times. See

figures 91 and 92.

Figure 91- Shows a close view of a factory fit D frame cylinder

bolt head. This smaller, offset bolt head is slightly narrower

than the E/I type [approx. .073" vs. .099"] and is top bevelled

only about .005". Forming the D bolt cylinder riding point

requires a more pronounced profile curve at the lower edge of

the bolt. Don't over curve.

Figure 92- Shows hand checking the bolt head cylinder riding point after polishing the bolt head. The head must slide down

the bolt slot lead without gouging, and drop easily into the bolt

slot. The bolt head must fit the slot with minimum side

clearance. Inset shows clearance at top point with correct

crown at riding point.


Figure 93- Shows close views of E/I and D bolt heads. Normal

travel polishing on the sides [light, shiny marking] usually

indicates a zero sideplay head fit inside the frame window.

With correct bolt head fit in the cylinder, heavier drag marks

may indicate that the bolt window is rough or burred.

Inspection points are shown.

Figure 94- Shows a close inside view of an I frame cylinder

bolt window and bolt stop ledge. The bolt window can be

lightly de-burred or re- squared if left uneven from a previous

fitting. Do not oversize the bolt window or alter the bolt stop

ledge. Arrows show punch peening zones for adjusting, or

closing, bolt windows.

Bolt Head Width and Frame

Window Fit

The sides of most previously fit bolt

heads may require no more than light

polishing with #600 sandcloth. Frame

windows seldom need more than light corner de-burring. Refitting problems

are found when bolts have been poorly

replaced and when worn bolt windows

have been peened incorrectly, or, with

older frames, weren't adjusted at all.

See figures 93 & 94. There are two

basic fitting rules covering cylinder

bolts and bolt window width:

1. The bolt head must fit freely and

easily into each of the cylinder's bolt slot cuts, and with near zero

sideplay.

2. Short of restricting travel or

binding the cylinder bolt head, the

bolt window in the frame should

control cylinder bolt position and

allow no sideplay at the bolt head.

From the above rules, it also follows

that:

1. When a cylinder bolt head is worn, misfit, or loose in the

cylinder's bolt slots, the bolt must

be replaced.

2. When cylinder slot fit is correct,

but the frame's bolt window

allows side movement, the

window should be adjusted to

eliminate play.

3. Windows are adjusted by

carefully punch-peening the

frame area just to the left of the bolt window. See fig. 94.

4. Protect frame window by placing

a backup gauge insert inside,

before peening. Caution: bolts

that are loose on their pivot

screws deflect, and only appear

loose in the frame window. Check

before adjusting window. See fig

96.


Check Bolt-Pivot Fit

This is an important, and yet

sometimes ignored, fitting step.

Correct bolt pivot screw fit and the

resulting light tension placed on the

bolt body holds it firmly against the frame. This, in turn, allows the right

side of the bolt to correctly align and

lock the cylinder. At the lower end of

the bolt tang, this solid body position

also helps maintain a consistent bolt

actuator tip location above the

rebound lever cam, necessary for

correct rebound pick up [drops the

bolt] and bypass [snaps it back up].

1. Temporarily install the cylinder bolt and bolt pivot screw in the

frame. Do not install the bolt

spring.

2. Thread in the bolt pivot screw.

Tightly seat the screw shoulder

against the frame.

3. Then check fit by hand working

the bolt.

4. When the bolt is fit correctly [still

without the bolt spring installed],

screw head tension on the bolt

and frame should cause the back of the bolt to drag slightly when it

is moved by hand.

5. If the screw head is too tight, bolt

friction will be excessive, and the

bolt will bind on the frame.

Lightly stone the friction area at

the back of the bolt. See fig. 96.

6. If bolt fit is loose, lightly relieve

the bolt pivot screw shoulder

contact area inside the frame with

a piloted shoulder counterbore- [5/32" O.D. X .095" pilot].

7. Do not fit the bolt pivot screw. If

it shows evidence of alteration-

replace it.

Figure 95- Shows an E/I cylinder bolt [without spring]

temporarily installed in the frame to check cylinder bolt body

to frame fit with the bolt pivot screw fully seated. When the

bolt body and frame are correctly fit, [less spring] the back of

the bolt should drag lightly against the frame when the pivot

screw is tightened.

Figure 96- Shows stoning-polishing areas on the back sides of

D and E/I cylinder bolts, at "A", where friction areas are lightly

stoned to reduce pivot bind. At "B", the frame is lightly

counterbored to increase pivot screw seating depth and

tighten a loose cylinder bolt. The 5/32" counter bore used for

this work is shown at right.


Figure 97- Shows close views of an E/I model bolt spring,

above, and a D model bolt spring, below. Both springs run

approx. .076-077" in diameter. The E/I spring is slightly

"coiled-in" and rounded at the bottom, and measures about

.340" in length. The shorter D spring is rounded at both ends

and measures just at .310", overall.

Figure 98- Shows checking bolt engagement and lock-up after

the bolt, bolt spring, and pivot screw nave been installed. The

cylinder is then locked in all six positions and the latch pin

inserted. The bolt head must engage about 1/32" [.032"- .035"].

Once locked, the cylinder must not

roll, or back roll, out of the locked

position.

Final Install Cylinder Bolt, Spring

and Bolt Pivot Screw

In D, E, and I frames, the easiest way to install the bolt spring [without

losing it] is:

1. Drop the bolt in the frame and

position it at the top of its milled

recess.

2. Insert the spring into its tunnel at

the bottom of the bolt, rounded

end down.

3. Slip the base of the spring into its

seat in the frame. 4. Then, align the bolt, hold the

spring, and install and seat the

bolt pivot screw. Caution: Bolt

springs must be strong enough to

hold the locked cylinder bolt

position, but not so long that the

coils stop the bolt before it can

clear the cylinder. D, and E/I bolt

springs are coiled-in, or rounded

at the bottom to fit the frame's

bolt spring seat.

Check Cylinder Bolt Lockup

In D, E, and I frames, the bolt

provides both cylinder lockup as well

as rotational alignment with the barrel.

The hand provides secondary lockup,

and prevents cylinder back-roll. See

figure 98.

In most frames, high point [right side]

cylinder bolt engagement will run

about .032-.035" [or just at 1/32"]. To provide this engagement, the bolt head

in D, E, and I revolvers extends about

.080" above the frame, or just a little

over 5/64". Measuring bolt head

height above the frame is a useful

reference, but can't guarantee correct

bolt head engagement in the cylinder.

The bolt must lock the cylinder, hold

alignment, and prevent the cylinder

from rolling out of locked position.

See figure 98.


Elevate E/I Frame Bolt Head

When the cylinder bolt head is worn,

misfit, or has been overly corner

dressed on the low side, [the cylinder

back- rolls] and enough bolt head

material remains, the head can be raised by filing or stoning the stop

area below the head. See figure 99.

1. Estimate the amount the bolt head

must be elevated.

2. File approximately half the

estimated amount from the bolt

stop shoulder.

3. Temporarily reinstall the bolt, and

re-measure height.

4. Repeat 1-3 until the bolt head is at the correct height. Caution: Filing

or stoning the frame's bolt stop

ledge is incorrect and can damage

the frame. Remember: as the bolt

head is raised, the actuator tip

lowers. The rebound lever will

require adjustment. See figures

141 through 152.

Elevate D Frame Bolt Head

Two different D model bolts are found. The later [flat stop shoulder]

replacement type is elevated in much

the same way as the E/I bolt. With the

earlier style, the stop shoulder step is

usually the first contact point. With

this type bolt, slight lowering of the

step raises the bolt head. Take extra

care not to file or stone the side of the

bolt head. See figure 100. Some

stepped-stop type bolts will have

frame seated and/ or may have been previously refit. Stop contact may be

found in the flat area above the step. If

enough material remains with these

bolts, adjust the upper step first. After

elevating, always check and refit bolt

heads.

Figure 99- Shows a close view of an E/I type cylinder bolt head

and stop shoulder. Bolt heads are elevated by carefully filing

and/or stoning the top of the stop shoulder, a little at a time,

until correct head height is reached. The bolt stop ledge in the

frame needs no fitting beyond very light de-burring. It must not

be altered.

Figure 100- Shows two different styles in D frame cylinder bolt

stop shoulders. The bolt shown at "A" is an earlier type which

features a combined bolt stop and stepped bolt aligning-

adjusting shoulder. The later replacement bolt, at "B", has a

single, flat stop surface. D bolts are also elevated by stop

shoulder adjustment.


Figure 101- Shows close views of both sides of a late I model trigger. Side and end views of an early E

trigger are shown, at right. Important surfaces are identified. In Colt D, E and I revolvers, the trigger is a

multi-function part, directly responsible for timing hand, rebound lever, and safety linkage positions. Via

the rebound lever, the trigger also sequences the cylinder bolt and rebounds the hammer. For these

reasons, the condition and dimensions of all trigger surfaces are critical.

Figure 102- Shows close views of both sides of a late D model trigger. While this smaller trigger is very

similar to the E/I, it is not exactly a scaled down version. Hand pivot pin position, hand operating angle,

and single and double action hammer release points are slightly different with this trigger. Full

understanding of trigger function has always been the real key in troubleshooting any double action

revolver. This rule is especially true with D, E and I frames.


Detail Inspect D, E, and I Single

Action Sears

1. The sear point must be sharp and

straight, with the edge at 90 degrees to

the side of the trigger. If the sear is

chipped, pitted, damaged, or misfit, replace the trigger.

2. The sear point correction bevel at

the top of the sear must not be over

cut, or over polished. See figs. 105 &

106.

3. The top of the S.A. sear extension

just behind the sear correction bevel

[D.A. strut cycling surface] must be

smooth for correct function.

4. The sear face must be smooth. The

bottom hammer engagement corner must not be cut short. See figures 105,

106 and 202, in Section II.

5. The single action trigger cycling

shoulder [under sear extension] must

be polished for correct S.A. function.

Inspect Safety Linkpin Head

1. Safety link pins must be undamaged

and secure in the trigger. Pin heads

must not be altered beyond the slight

fitting necessary to prevent head drag as the pin cycles the safety lever inside

the cylinder bolt recess. See figs. 103,

104, and 111 thru 115.

2. If the link pin head shows evidence

of drag marking, check to make sure

the pin is fully seated in the trigger.

3. If fully seated, lightly stone the

head and recheck for cylinder bolt

contact.

4. Whether the safety link pin required

fitting or not, always check pin head fit in the safety lever slot. Once

installed, the head must not slip out of

the engagement slot in the safety

lever.

Figure 103- Shows a close view of an E/I type S.A. sear and

safety link pin. Inspection points are: 1. sear point, 2. sear face

surface, 3. S.A. trigger cycling shoulder [under sear extension],

4. safety link pin and bevelled head, 5. D.A. strut cycling

surface. If any of these areas are damaged, pitted, or misfit,

replace the trigger.

Figure 104- Shows a view of the sear side of a D trigger. Sear and safety link inspection points are the same as E/I

model triggers. With D triggers, the safety link pin is square

cut rather than bevelled, and the inside corner of the single

action trigger cycling shoulder is radiused for correct S.A.

timing- don't alter.


Figure 105- Shows an I model SA sear. As sear angle is moved

from zero to "A", the bottom engagement corner, or "sear seat",

at "C", rides lower in the cocking notch, and the sear point

rides lower. Both engagement and pull increase. As angle is

changed toward "B", the higher seat raises the engagement

point, decreasing SA pull.

Figure 106- Shows a D type SA sear. Pull is set in the same

way, mechanically; however, in finishing, the much thinner D

sear requires extra caution to prevent overcutting and/or

shortening the sear face. Short triggers can mis-time DA

hammer release early, and cause "strut-hits-trigger" problems

in single action.

D, E, and I Single Action Sears and

Trigger Pull

In D, E, and I models, the exact

finished angle of the single action sear

face is not fixed. In final fitting, sear

angle will vary somewhat with the individual frame and hammer. Sear

face angle has two basic functions:

first, the resulting bottom corner, or

sear seat position, determines just how

high the sear point will ride in the

hammer's SA cocking notch- after

that, the face angle then provides

clearance for the hammer toe on

release. In this design, the hammer's

cocking notch over-engages the sear

by a number of degrees. The rule is: The higher the sear contact inside the

hammer's cocking notch, the lower the

force, or pull, that is needed to

overcome the rest of the notch. See

figs. 105 and 106.

Safe S.A. Trigger Pull

Factory minimum safe trigger pull is

listed as 3 lbs. for D and E frames, and

2 1/2 lbs. for I frames. To be safe,

hammers must not "push-off" at these specifications. With D, E, and I model

sear engagements, correct trigger pull

works out to be approx. 2/3 sear

engagement fitting and 1/3 mainspring

pressure. Typically, factory fit single

action sear point engagements are set

about 2/3 of the way up the hammer's

SA cocking notch, and normally

provide the best single action trigger

pull without push-off. Caution: The

above is based on hammer cocking notches in original factory condition.

Do not alter cocking notches.


Push-Off Caused by Trigger Sear

Mis-fitting

When a hammer in original factory

condition is single action cocked, and

the S.A. cocking notch can't overhaul

[over engage] the single action sear with the sear point below the over

engagement ledge, the hammer will

push off. See figure 107. Depending

on surface polish, spring pressure, and

other variables, misfit triggers may or

may not hold S.A. cocked position at

all, and when they do, it is largely by

friction. Note: Sear point engagements

just at, or fractionally below, the

beginning of the over engagement

ledge, are not reliable- and may still allow hammer push-off. Sear points

that are cut on an angle may ride, or

straddle the engagement ledge- and

also cause push-off.

Hammer Alteration

When the hammer's cocking notch is

altered, the hammer can't catch the

single action sear point below the

cocking notch over engagement ledge,

because the ledge has been either changed or eliminated. While I have

never seen a brittle D E, or I hammer,

it's always possible that a re-heat

treated hammer might exist. A broken

engagement ledge could also cause

push-off. Part of the safe trigger pull

definition states: "the hammer must

not push-off". This includes push-off

from either side, as well as the back.

Push-off conditions could cause an

early single action discharge, and are potentially unsafe for that reason.

Figure 107- Illustrates the main cause of hammer "push-off".

The mis-cut sear face shown places the sear point above the

over engagement ledge in the hammer's single action cocking

notch. In this extreme example, the sear face is both over-cut

and at the wrong angle. With too little sear over engagement, hammers push off.

Figure 108- Shows a close view of an altered E model hammer

SA cocking notch. The edge of the over engagement ledge has

been stoned and rounded off. This single action cocking notch

can no longer over-engage. Even a well fit sear can't safely

hold this hammer. The rule is: leave SA cocking notches in

original condition.


Figure 109- Shows E/I model trigger-frame fit inspection

points. Frame pin diameter and trigger fit on the frame pin are

checked at "A"; bolt drag inside the trigger's bolt clearance

recess is checked at "B"; safety link pin head clearance is

checked at "C"; and bolt contact [mostly in early E models] is

checked at "D".

Figure 110- Shows D model trigger-frame fit inspection points. At "A", frame pin diameter and trigger fit on the pin are

checked; at "B" and "C", drag at contact surfaces of both

trigger and bolt is checked; and safety link pin head contact is

checked at "D". D frame pin drag is usually found only when

link pins aren't seated.

Check Trigger-Frame Fit

If the particular revolver and internal

parts being checked are still factory

original, very likely the trigger is just

as initially fit. A simple, quick

inspection for drag marks and correct frame pin fit is generally all that is

needed. But, when parts have been

replaced, and especially when late

parts have been installed in earlier

models, make the following checks.

1. Inspect the inside of the trigger

and the side of the cylinder bolt

for drag.

2. When trigger drag is found,

carefully dress the bottom corner of the E/I bolt. See figure 109.

3. With D models, lightly dress drag

areas on the inside of the trigger

and on the side of the bolt. See

figure 110.

4. Check safety link pin heads for

drag marking. When present, seat

the pin.

5. If the pin is already seated and

still drags, lightly stone the head.

Remember; the pin head must be

large enough to hold the safety lever captive, once engaged.

6. Check for bearing surface drag

marks on both sides of the trigger

indicating possible excess trigger

width or a tight sideplate fit.

Shiny, self polishing marks are

normal, and do not require

additional bearing surface

dressing.

7. If bearing surface drag marking is

present, check the sideplate for raised areas and/or burrs at trigger

location. Level any found.

8. Also, lightly polish the left,

sideplate side, of the trigger on

#600 sand cloth.


Detail Inspect E/I Safety Assembly

1. Inspect the safety lever and upper

safety. Both parts must be straight

and unbent.

2. Check safety lever pin slots at

both ends. Inside slot bevels must be intact. Both slots must hold

safety link pins positively, once

engaged.

3. Inspect both hammer and upper

safety link pin for pin head

contact or drag.

4. If indication of drag is present,

lightly dress head of the link pin

and recheck fit. Don't undersize

the pin head. The head must not

come out of the slot, once engaged.

5. Check positioning ring. It must be

unaltered and fit the outside of the

hammer boss without bind or

sideplay.

6. Inspect the 90 degree hammer

block extension on top of the

upper safety. The blocking

extension must be at full factory

width of .100"- .101" to

effectively block the hammer. Do

not under size the hammer block extension. Warning: Don't fail to

detail inspect all safety system

parts. Replace any part that is

incorrect, worn, or shows any

sign of alteration.

About E and I Safeties

The E type upper safety was used

from the beginning of the Army

Special Model to the end of Official Police production in 1969. The E

upper safety was slightly modified for

use in the I model variation in the

early 1950's. This created a new and

separate part number. I frame upper

safeties are quickly identified by their

plated finish.

Figure 111- Shows a close view of a connected I model safety

lever and safety. A closer side view of the safety, at right,

shows the hammer block and bottom link pin. Arrows indicate

inspection points. Safety assemblies should be closely checked

against correct factory parts. Replace any questionable safety

or safety part.

Figure 112- Shows an E model safety lever and safety. For

comparison, the I safety is shown at right. Both E & I models

use the same #50489 safety lever, but upper safeties are

different. I frames use a #51657 upper safety. E models now

use the #50372 replacement assembly since the original upper

safety is no longer supplied.


Figure 113- Shows a connected late D model safety lever and

upper safety. A side view of a late upper safety is shown, at

right. At top, D trigger and safety link pins show the D model

safety link pin head style. In fitting, always compare safety

parts against correct factory new parts. Always replace

questionable parts.

Figure 114- Shows both early and late D model upper safeties.

The #56094 D safety lever used throughout production is

shown, below. Upper safeties are not available separately, but

only as a part of the correct assembly. With old style hammers,

use the #56171B safety assembly, and with late hammers use

the #56614 assembly.

About D Frame Safety Assemblies-

Inspection points with D frame safety

assemblies are basically the same as

with E/I models. See figures 111, 113,

and 114. Early D frame upper safeties

function and look very much like slightly shorter versions of E model

upper safeties. Also see inset

illustration in figure S-l. When the

new D frame hammer replaced the old

design, the original safety hammer

block extension was simply extended

a bit further upward [about .100"] to

engage the new hammer's higher

safety hammer block seat. The new

extension was slightly offset so that

frame modification was unnecessary either in production- or for parts

replacement. What this amounts to is

that early and late upper safeties do

not mix or interchange.

When a late style hammer is installed

in an early D frame, the safety

assembly must also be replaced

because the early style upper safety

hammer block extension is .100" too

low and cannot stop a new style

hammer.

Late and intermediate D hammers

were manufactured with a milled

clearance recess for the upper safety

link pin, eliminating the possibility of

drag or contact at that point. When a

late style safety hammer block

extension is not correctly fit, or is bent

even slightly forward, it may drag or

bind against the frame as it tries to

move into the blocked hammer position. This is sometimes mistaken

for a rebound seat problem.


Check Trigger and Safety Assembly

Linkage in Frame

After the trigger, trigger safety link

pin, safety lever, and upper safety

have been individually detail checked,

they should be installed in the frame and then function checked as follows.

1. Check trigger and safety for

correct, no-drag fit at the hammer

boss and inside the frame's milled

upper and lower safety recesses.

2. The safety assembly must move

freely in the frame without

lubrication and with no noticeable

drag or bind.

3. If the upper safety arm, or the ball at the end of the arm, drag while

inside the frame slot, lightly stone

safety contact points until drag is

gone. Don't undersize the safety

hammer block.

4. With hammer in frame, check

upper safety position. See fig.

115. Also, check hammer skirt

safety link pin clearance. Chamfer

hammer skirt as necessary.

Check and Install Latch Pin

The cylinder latch pin has the primary

job of latching and then holding the

cylinder closed. But, subject to

existing vertical tolerance, it also

maintains the rear of the cylinder on

centreline, and holds this position

during the hand up, locked cylinder,

firing phase. Since there is the

tendency for a slightly long bottom

hand to push up on the back of the cylinder during firing, latch pin fit

should be as close to zero clearance as

possible. Latch pins showing even a

small amount of wear should be

replaced. See figure 116.

Figure 115- Shows, at "A", operation of an I safety assembly

being checked after installation. Arrows show locations to

check for drag in the frame. An I frame hammer is temporarily

installed at "B" to check correct safety [hammer block] position

between the frame and the hammer when the trigger is fully

forward.

Figure 116- Shows micrometer checking a latch pin, at "A"

before installing it in the frame at "B". Latch pins should fit

frames with near zero clearance. E/I frame latch pins measure

just at .250" diameter, and D frame latch pins measure in at

.199" diameter. When any amount of wear is evident, always

replace the pin.


Figure 117- Shows close views of E and I model hammers. Inspection areas and sub-part names are also

shown. Although the I hammer evolved from the E, differences in firing pin design and location make the

two hammers non- interchangeable. Otherwise, these hammers are so similar that the #50486 D.A.

hammer strut, #50454 strut spring, #50453 strut pin and #56105 hammer stirrup fit both hammers.

Figure 118- Shows close views of left and right sides of a late style D model hammer. Sub-part names

and inspection areas are shown. The D hammer has more machining detail on it than any other Colt

hammer. Early style D hammers are no longer available, but are replaced with late style hammers,

providing the matching late style #56614 safety assembly is installed with the hammer update. The same

#56107 D.A. strut, #50400 strut spring, #55105 stirrup, and #56108 strut/stirrup pin have been used

throughout D model production.


Check D and E Model Firing Pins

D and E firing pins semi- float on the

hammer's firing pin rivet. This style

pin must be both straight enough and

vertically free enough to self align as

the tip passes through the cone just inside the recoil plate.

1. Check firing pin for free

movement in the hammer. If

resistant or stuck, soak the entire

hammer assembly in penetrant or

acetone.

2. If the tip is bent and strikes

primers to the right or left,

remove the firing pin and

straighten it on a bench block with a brass hammer.

3. Reinstall firing pin, replace rivet,

peen, and then resurface sides of

hammer.

4. If primer indentations are low,

elevate by stoning the top back

edge of the firing pin. See figure

120.

5. If primer indentations are high,

stone the bottom back edge to

lower the firing pin. Note:

Marking the tops of shell casings with a felt tip pen will provide a

helpful directional reference.

In addition to weak mainsprings and

excessive headspace, bent or

misaligned blade type firing pins are

one of the three main causes of

misfiring and erratic primer ignition in

D.A. revolvers. Primers must be

indented at a point fairly close to the

centre of the anvil inside the primer for consistent, even ignition. Firing

pin strikes just at the edge of the anvil

may or may not generate enough

internal heat to fire the primer. See

figure 120.

Figure 119- Illustration shows a top view of a D model recoil

plate and a bent firing pin. Except for overall size, D and E

firing pins are nearly identical. For correct function, firing pins

must be perfectly straight and free to vertically self align in the

hammer as the tip passes through the opening in the recoil

plate.

Figure 120- Illustrates the two areas used in adjusting D and E

vertical firing pin alignment. Stoning the back of the pin, at

"A", rolls the tip further upward as it passes through the recoil

plate; stoning at "B" lowers the tip. Using only tired shell

casings as reference, align firing pins by adjusting pin strikes to

centre of primers.


Figure 121- Shows both I and J type, in-frame inertial firing

pins with correct, matching springs. Both I and J parts are

shown here for purposes of identification, since the longer,

thinner J model pin will drop into an I frame. Before installing,

be sure that the firing pin and spring are correct and in good condition.

Figure 122- Shows correct installation sequence for the I model

firing pin and spring. Even though some parts diagrams show it

reversed, the large end of the tapered I model firing pin spring

should face the bottom of the I frame firing pin tunnel. Always

make sure the frame tunnel is clean and free of dried oil

residue.

Check I Model Firing Pin

With I models, the firing pin should be

checked for tip condition and evidence

of separation [and, as well, to make

sure it's a correct part]. Most I frame

firing pins and springs checked will be factory correct. However, now and

then you will find a wrong firing pin

installed. In a classic example, an I

frame [Python] was brought in with a

primer puncturing problem. Primers

showed no real indication of abnormal

pressure. Headspace was correct, but

pin protrusion measured in at .065"-

far in excess of the .056" factory

specified I model maximum. After

some discussion, the customer finally told us that he had broken the original

firing pin during dry firing practice,

and then had taken the revolver to a

repair shop. The man rummaged

around in a box, found a spring and

pin, and dropped them in. As it turned

out, the pin was a J frame Colt part,

but the spring was unidentifiable. Use

only the correct #51231 firing pin and

#51232 firing pin spring in I frame

revolvers. The J model firing pin

shouldn't be used even temporarily for the following reasons: the pin is too

long; diameter is too small; and tip

position is erratic in I frames.

Install I Firing Pin

1. Drop in firing pin and spring. See

figs. 121 and 122.

2. Start firing pin stop plate in the

frame.

3. Punch depress the pin head. Slide stop plate down until firing pin

head snaps into place in the pin

port.


Check Firing Pin Protrusion

The fact is that firing pin protrusion

should always be checked during

refitting. Reassembly is the logical

time to gauge check and/or correct a

long or short firing pin problem.

Checking firing pin protrusion is an easy, but much too frequently skipped,

inspection step. See fig. 123. When

too long, firing pins can puncture

primers. When too short, misfires can

result. Check firing pin protrusion

against the following table:

Frame/Cal. Min. Max.

D/22L.R. .030 .035"

D/32N.P. .042 .056"

D/38Spl. .042 .056"

E/22L.R. .030 .040"

E/38Spl. .040 .050"

I/38Spl. .042 .056"

I/357M .042 .056"

Check Hammer Stirrup and

Rebound Seat

1. Visually check stirrup. The arm

must be straight. The crosspin

should be in good condition and

filed to a width slightly narrower

than the body of the hammer, but

not narrower than the main-

spring. If questionable, replace.

See figure 124.

2. Check the stirrup pin for tightness

in the hammer. If loose, replace the pin.

3. If stirrup pin is still loose, lightly

stake the pin on both sides. Level

raised material.

4. Closely inspect rebound seat. The

seat should show rebound contact

marks only.

5. If the rebound seat has been

altered in any way, replace the

hammer.

Figure 123- Shows gauge checking for correct firing pin

extension with a firing pin protrusion gauge. This tool

measures how far the firing pin extends past the recoil plate.

The firing pin displaces the inner stem of the gauge; extension

is then measured with a micrometer; the amount of extension

equals firing pin protrusion.

Figure 124- Shows a close view of an E/I type hammer stirrup,

stirrup pin, and rebound seat. Although appearance is

somewhat different, inspection points with the D model

hammer are the same. Beyond staking loose pins and light side

polishing, the body of the hammer, and the rebound seat, must

not be altered.


Figure 125- Shows a close view of an assembled I model

hammer, D.A. hammer strut, strut pin, and spring. For smooth

double action function, the bottom tip of the strut can't be flat,

squared off, or rough, but must be finished to a sharp point,

then polished and rounded slightly with #600 sandcloth. Do not shorten the strut.

Figure 126- Shows examples of factory fit I and D model DA

struts. Struts should be fit only to specific triggers. If let out too

far, the strut may contact or strike the sear on SA release. If let-

out isn't enough, DA hammer release can be early [before

cylinder locks]; firing pin strikes can be light and off-time;

misfires can result.

Check D.A. Hammer Strut

Even a well fit DA strut can be a

problem if it's oil stuck.

1. The strut must snap back instantly

when released. 2. If return is sticky or slow, clean

parts in solvent, check the spring,

reassemble, and recheck strut return.

3. The strut tip must be pointed and

long as possible.

4. If strut tip is not smooth and lightly

rounded, polish the tip with #600

sandcloth.

5. Drop hammer assembly in the

frame and check SA-DA function and

strut let-out. 6. Let-out is increased by very lightly

filing the stop shoulder at the top of

the strut. If let-out is already

excessive, replace the strut. See

figures 125 & 126.

7. If the strut pin is loose, stake the pin

to the hammer body side with a

rounded staking punch. Level staking.

About Strut Let Out-

The factory rule about strut let-out is: the strut should be as long and as far

away from the hammer as possible,

but must not interfere with the sear

when the hammer is S.A. released.

Adjust strut let-out only when bolt

timing is correct. The strut must

release the hammer in D.A. mode only

after full cylinder lock up. Check strut

function in both slow and fast D.A.

Then, check in S.A. mode to make

sure the tip of the strut easily clears the sear point as the hammer is

released. Caution: If the bottom hand

[second finger] is long, it may hold the

sear point low, possibly causing

contact with an extended strut. Correct

problem by fitting the hand.


Check Single Action Cocking Notch

and Hammer Toe

D/E/I single action cocking notches

are designed to overhaul [over

engage] a correctly fit sear point. With

the sear point engaged, the ledge at the top of the cocking notch extends past,

or overhangs, the sear, forming a

combined angle of less than 90

degrees. As the trigger is squeezed,

the sear pushes the engagement ledge

back slightly to escape the cocking

notch. Without the sear, the cocking

notch angle is greater than 90 degrees.

Some take this to mean that modifying

the SA notch is O.K. and won't hurt

anything. This is a gross error. Any alteration of the notch can destroy the

over- engagement feature, and can

render the hammer unsafe.

Hammer Toe Fitting

When polished, the flat trigger pickup

surface above the toe, and the

chamfered corner at the forward edge

of the surface help make single action

trigger pick-up and cocking much

smoother. The 45 degree chamfer at the top forward corner of the toe cuts

cycling drag by allowing the toe to

clear the bottom corner of the sear

easier. The bottom bevel, just above

the engagement ledge, helps cam the

single action sear point into cocked

position. Anything greater than very

light polishing at the bottom bevel

reduces the engagement ledge and, in

fact, alters the cocking notch.

Hammers with thin toes, over-cut chamfers, bevels, and/or cocking

notch alteration must be replaced.

Figure 127- Shows a close view of an E/I type hammer toe.

Inspection areas are shown. Except for light contact polishing

from normal use, all surfaces should be in original factory

condition. The flat area at the top of the toe is polished and top

corner chamfered for smooth S.A. operation. No other fitting is

done.

Figure 128- Shows a close view of a D model hammer toe.

Inspection points are the same as with E and I hammers. However, these surfaces are much smaller and harder to see.

Good lighting and a magnifying glass are needed for this job.

D, E and I hammers are heat treated, but do not require case

hardening.


Figure 129- Shows an I model hammer and trigger, now ready

for mating/function pre- check after final SA sear and DA strut

fitting and inspection. This test is done in D, E, and I models

by cycling the trigger and hammer while simulating mainspring

pressure with fingers. This rules out most trigger/hammer

problems.

Figure 130- Shows an I hammer installed and ready for frame

fit checks. Possible frame- hammer drag check points common

to D, E, and I hammers are shown above. When latch pins or safety assemblies have been replaced, always check for contact

or drag where the hammer block crosses the back of the latch

pin.

Hammer-Trigger Pre-check

The following steps pre-check for

correct single action sear engagement

and release, and correct double action

strut pick-up and hammer release.

1. Simulate spring pressure on

hammer and trigger, and slowly

SA cock the hammer until the

sear cams into the single action

cocking notch.

2. While holding forward pressure

on the trigger, try to push the

hammer out of the notch by

applying pressure to the hammer

spur. The hammer must not push

off. [The assembled action push- off test is done later with sideplate

installed.]

3. Hold forward pressure on the

hammer spur and slowly squeeze

the trigger. The sear should

separate crisply.

4. Check DA by maintaining

forward pressure on hammer, and

slowly squeezing trigger until

strut by-passes trigger.

5. Then return the trigger and make

sure the double action strut returns over the sear. If sear work

is needed, see figure 202, Section

II

Check Hammer Fit in Frame

1. The hammer should pivot freely

on the hammer boss without

contact on the frame side, and

should clear all safety linkage and

safety link pins. I hammers require "undercutting", or

chamfering the skirt, to prevent

catching safety link pin heads.

2. The hammer stirrup must be

straight and the crosspin must

clear the frame.

3. Lightly dress any contact marks

on sides of hammer, and remove

burrs and high spots in the frame.

See figure 130 for fitting areas.


About D, E, and I Hands-

If, at initial pre-check, hand function

seemed normal, and the hand rotated

the cylinder to bolt index, it's very

likely that hand fit is either correct or

is in need of only slight adjustment. The sections that follow cover this

subject in detail.

Nearly every surface of the hand has a

specific job. With this in mind, it's a

good idea to first discuss basic hand

function and fitting points. See figures

131 & 132.

1. The hand's pivot pin connects the

trigger and hand and times them

together. 2. The tensioning cam at the bottom

of the hand's rebound lever slot

converts downward rebound lever

pressure to forward hand tension.

3. The front of the hand, or let-out

shoulder, controls the angle of the

hand's upward travel and

determines ratchet engagement.

4. Hand thickness, and/or a slight

bend just at midpoint, keeps the

hand in positive position at the

ratchet, and eliminates bind, or gouging at frame or sideplate.

5. The top hand [or "top finger"]

engages the ratchet first and

rotates the cylinder.

6. The bottom hand ["second

finger"] picks up rotation and

indexes the bolt, and then

becomes a secondary cylinder

lock under the ratchet.

7. Both the top and bottom hand are

adjusted for correct cylinder rotation and index.

8. Various hand edge bevels and

chamfers provide the necessary

shell head and hand operating

clearances.

Figure 131- Shows close views of a factory fit E/I model

cylinder hand. Inspection and fitting points are indicated. The

#50487 I hand also replaces the narrower #50456 original E

hand. When fit to an E frame, the wider I model replacement

hand requires less inward bend for correct ratchet contact and

frame clearance.

Figure 132- Shows close views of a factory fit D hand.

Inspection points for D, E, and I hands are the same. In fitting,

D, E, and I hands are bent very slightly at mid-point for correct

frame clearance and proper ratchet contact. This step provides

operating clearance, eliminates hand gouging, and controls side

play.


Figure 133- Shows a late D frame's hand guide surface. To

prevent hand interference, level raised edges found at the

ratchet recess corner with a fine stone and lightly break the

sharp corner. Level any ridges in the guide surface high enough

to interfere with the hand- but do not lower or otherwise alter

the guide surface.

Figure 134- Shows a late I frame ratchet recess and hand guide

surface. The sideplate's hand slot is shown at left. The same

surfacing steps apply, except the E/I frame is large enough that

the corner of the ratchet recess should be lightly chamfered.

When well fit, the hand will leave a shiny contact mark in the

sideplate slot.

Check Hand Guide Surface

Sometimes, a fairly new revolver may

be found with noticeable frame-hand

drag as the cylinder is being rotated.

With this particular problem, drag

generally starts after the hand has lifted part way. Drag may, or may not,

continue through the rest of hand

travel. This is a bit different than

gouging caused by a mis-adjusted

hand. In a still assembled revolver, a

fast test to rule out whether there is

another cause of drag or bind [such as

a long hand or thick ratchet lug], is to

open the cylinder and cycle the hand

by itself. But, if drag was noticed on

initial pre-check, and the revolver is already disassembled, closely inspect

the frame's flat hand guide surface and

also the edge where the hand travels

forward past the corner of the ratchet

recess. See figs. 133 and 134.

Typically, the following cause frame

related hand drag:

1. The frame guide surface is left

ridged or rough from dull tooling.

2. The hand must overcome a

machining ridge or ratchet peening marks at the forward

corner of the ratchet recess.

Hand Drag & Polishing

Frame drag caused strictly by the hand

usually is because:

1. The hand is over-bent, making it

drag either the frame, sideplate, or

ratchet. 2. The top hand corner is

unchamfered and sharp.

3. The hand is too thick, causing it

to bind or drag between frame and

sideplate.

4. The sides of the hand have not

been polished.


About Hand Let-Out, D, E, and I

Models-

Hand fit is critical in D, E, and I

revolvers. New factory replacement

hands are made somewhat oversize so

that enough surface material is available for final fitting. In order for

a revolversmith to fit the hand to do its

main job of rotating the cylinder to

index with the cylinder bolt, the first

job is to pre-fit the hand to function

with the frame and, after that, with the

action. The last step is to adjust top

and bottom hand length. Differences

in frame post positions and thickness,

as well as slight differences in

triggers, make fitting let- out the first step. Except for chamfering and

polishing the flat sides of the hand,

other fitting steps follow let-out. See

figures 135 and 136.

Let-Out Adjustment

The only real difference in letting out

D and E/I hands is that the smaller D

hand elevates on a greater angle. It

enters the ratchet faster and a little

further back than E and I model hands. In letting-out hands, a good fitting rule

is that the hand's lower front adjusting

surface should be carefully filed until,

at full hand elevation, the top hand is

let out as far as possible, but short of

tip or forward point contact at the

bottom wall of the ratchet. This rule

applies even when the top hand is too

tall. When in the lower rest position,

the tip of the top hand cannot extend

past the frame's ratchet recess.

Figure 135- Shows a hand that wasn't let out enough. The front

edge of this hand correctly rides the frame post, but extra width

holds it back. Although the bottom hand lifts to a near normal

secondary lock position, the top hand skips by, misses the

ratchet, and can't rotate the cylinder. Let-out adjustment is

needed here.

Figure 136- Shows the let-out fitting area at the front of the

hand, at "A". The fitting area starts where the hand contacts the

frame's hand post, and continues to the bottom of the hand. The

upper hand area, at "B", is fit only when more shell head

cycling clearance is needed. D, E, and I hands are let out in the

same way.


Figure 137- Shows an I model action with the hand installed to

check forward hand tension. The rebound lever is also installed

for this check, and spring pressure is thumb simulated. While

there isn't an exact specification for forward tension, it must be

at least enough to hold positive hand-ratchet engagement.

Figure 138- Shows the action sides of D and E/I hands. As the

angle of the rebound lever's camming surface is changed

toward +, forward hand tension is increased. Make sure hand

let- out is correct before adjusting cam angle and forward

tension. A very small change in cam angle will increase

forward hand tension.

Check D, E and I Model Forward

Hand Tension

Some amount of hand tension is

needed to keep the hand engaged in

the ratchet as the cylinder rotates.

When a hand or rebound lever is replaced, the lever may not load the

hand's tensioning cam at the right

point. The result is low tension. See

figures 137 and 138. Check as

follows:

1. Install hand in the trigger. Make

sure the pivot pin is straight and

not undersized.

2. Install the rebound lever and trial

pivot pin. Position the rebound lever on the hand's tensioning

cam, then simulate mainspring

pressure.

3. Draw the hand back approx. 1/8"

with fingernail, and then release

it. It should snap back against the

frame post. Usual forward tension

is several ounces, or more.

4. If tension is too light or

nonexistent, carefully adjust

tensioning cam. See fig. 138.

5. If tension remains light, repeat steps 3 and 4.

Caution: Hand tension is easily

increased by adjusting the tensioning

cam angle, as shown in fig. 138. But

first, make sure that forward hand let-

out is correct. Carefully adjust the

cam, and only as necessary. The cam

surface directly affects rebound lever

position. A changed rebound position,

in turn, affects cylinder bolt timing. Replace misfit and/or overfit hands.

Nearly every fitting step involving the

bolt, trigger, and hand, will affect the

close relationship with these parts and

the rebound lever. Checking and/or

refitting the rebound lever is next.


Check D, E, and I Hand- Sideplate

Fit

If the flat sides of the hand weren't

polished earlier to remove drag marks,

lightly polish them now using #400

sandcloth on a flat surface and #600 sandcloth to finish. If no drag marks

are found, polish only with #600. Do

not undersize the hand. Polish sides

just enough to eliminate drag. See fig.

139. Then, install the sideplate, cycle

the hand, and check fit.

Replacement Hand Width

As finished replacement parts, D and I

model hands are somewhat oversize, and must be adjusted to correct width

and frame fit by polishing the sides

with #400 sandcloth. Top corners and

edges are chamfered for latch and

ratchet clearance. Also see figures 131

through 134. The #50487 I hand

replaces the original, and slightly

thinner, E model hand.

Early E Model Hand Width

When being polished and refit, the slightly thinner, original E model hand

may require a bit more bend, or off-

setting, at midpoint for correct

alignment between frame and

sideplate. Caution: Off-setting hands

may slightly shorten overall hand

length. Stretching may be needed. See

figs. 165-166. Replacing E Model

Hands When original E hands are

replaced, the later I model hand is

used. Wider I replacement hands can be fit to minimum sideplay in most E

frames with very little bend

adjustment. Polish both flat sides to

eliminate drag, as with I frames.

Figure 139- Illustration shows correct I model hand fit between

sideplate and frame guide surfaces. Little hand sideplay should

exist between the two. Adjusting bend centres the lower half of

the hand between frame and sideplate, helps eliminate drag and

gouging, and keeps the hand in positive ratchet contact.

Figure 140- Shows a hand adjusting fixture, used for bending

D, E, and I model hands at midpoint to align the hand,

minimize sideplay, and improve ratchet contact. Bending the hand too much, or too high, will bind the ratchet. The base of

the hand is off-set, a little at a time, with a brass drift and six

ounce hammer.


Figure 141- Shows a D and I rebound lever. The original E

rebound is no longer available, but the #50462 I model rebound

is so close that it is used as a replacement by factory service.

The four rebound lever inspection areas are shown. The

vertical position of the rebound's cam is critical in that it

determines bolt timing.

Figure 142- Shows a cutaway view of an I type rebound and

bolt actuator tip. The oldest rule in fitting rebounds is: there

can be no clearance between the cam and bolt actuator tip,

otherwise, the bolt may not pick up in time. But, if the cam is

long and/or the front triangle is mis-fit, the bolt may be unable

to bypass and drop.

About The Rebound Lever-

Long or short top and bottom hands

can't be realistically checked, or, for

that matter, finally adjusted, without a

direct reference to cylinder bolt

timing. The cylinder bolt is operated and timed by the position of the

rebound lever. The rebound lever rides

the tensioning cam in the hand, and is,

itself, timed by the position of the

trigger. In this way, a well fit rebound

lever begins to move upward [and

instantly begins to pick up the bolt]

when the trigger is moved in double

action, and almost instantly when the

hammer is moved in S.A. The rebound

cam, located just at the inside midpoint of the rebound lever, [see

figures 141 and 142] must be

positioned high enough in the frame to

correctly engage the cylinder bolt

actuator tip and, in turn, begin

lowering the cylinder bolt, instantly,

as the trigger is moved. But, the

rebound cam must not be so long, or

tightly fit, that it prevents the bolt

actuator tip from bypassing over the

bypass bevel at the front of the cam,

and dropping [snapping back] the bolt. See fig. 142. What this amounts to is:

If the bolt can't pick up on time- the

cylinder can't be rotated. If the bolt

can't drop [or snap back up], there is

no bolt timing point. This is why the

rebound is always checked and

adjusted, etc., before beginning final

top and bottom hand fitting work.

Doing this any other way involves

guesswork, and can cause mis-fitting.


Check Rebound Lever

If bolt timing was correct at the initial

pre-check, and the same parts were

used with very little surface refitting,

the rebound could still be correct, but

must be checked. However, if action parts were replaced, or the bolt head

was raised and refit, etc., the rebound

lever will have to be rechecked- and

will almost always require adjustment.

In checking the rebound, we are

asking the following basic questions:

1. Does the rebound cam pick up the

bolt actuator and cause the bolt to

respond instantly? (Is pickup

instant?) 2. Or, is the cam low (has clearance)

and bolt pickup is late? (Is pickup

delayed?)

3. Is the cam high? (The cam won't

let the actuator tip return back

over the rebound cam for the next

cycle.)

4. Is bolt timing correct? For

rebound adjustment, see the

following pages, and also rebound

work in Section II.

If Rebound Cam Is Too High

When a rebound cam is only slightly

high, bolt response will be instant, but

the bolt actuator tip can hesitate, or

have trouble returning over the outside

corner of the cam. If the rebound cam

was just a bit higher, the actuator tip

couldn't return at all. With one of

these, if you finally pick up the

actuator tip with a high rebound cam, it will hold the bolt slightly depressed.

In this case, the actuator tip might

appear slightly long- but is not. Do not

alter the bolt. The real problem is a

high rebound.

Figure 143- Shows an I model action with the rebound lever

installed for the rebound function check. The easily installed

and removed trial pin, above, is used during fitting, since the

rebound is usually taken out a number of times for fitting. The

cylinder is set aside until top- bottom hand adjustment and bolt

timing check.

Figure 144- Shows a close view of the rebound cam and bolt

actuator tip in a cutaway I frame. The height of the rebound

cam relative to the bolt actuator tip is easily seen. Cam position

was just at a no clearance fit. After bolt head elevation the cam

is now a bit too high, since the tip is lowered by the elevation

amount.


Figure 145- Shows the three rebound lever lowering areas,

above. #1 and #2 are most often used; area #3 is fit mostly with

new rebounds. The bolt return fitting areas under the cam are

shown below. Lightly polish the outer (right) side of the cam.

With E/I rebounds, only, lightly break the upper front triangle

corner

Figure 146- Shows typical bolt actuator tip return positions,

above. Slight bending of the bolt tang improves actuator tip

return position at the top of the rebound cam, and times bolt

drop. Small differences in parts fitting and internal frame

dimensions require fine tuning actuator tip position. See figs.

153 through 155.

Rebound Cam High, Cont.

Lower rebound cams by:

1. Filing or stoning the rebound

extension lever where it contacts

the hand's tensioning cam. This is a fine adjustment, only.

2. For larger adjustments bend the

main body of the rebound lever,

lowering the level of the cam. See

fig 215.

3. Slight rounding at the top front

bypass bevel corner- for E/I

models only. This is an initial

cam fitting step only, used to

improve bolt drop. But, the cam

may act as if too high or long without it. Use caution here: the

cam surface will be undersized if

the front bypass bevel corner is

moved too far back. This also

quickens bolt drop.

Poor Bolt Actuator Return

When rebound cam height is correct,

but the bolt actuator tip drags or

doesn't return to correct action cycling

(pick- up position) at the top of the cam, further rebound fitting is usually

required.

1. Lightly polish the outer (right)

side of the cam. With E/I

rebounds, lightly break the sharp

upper front triangle corner. See

figure 145.

2. Then, cycle and recheck for

correct bolt actuator tip return

position. See fig. 146.

Warning: Bend bolt tangs at this time-

only if bolt act- actuator tip return is

poor due to existing adjustment. At

this point, we are dealing only with

bolt actuator tip return. Don't make

further adjustments at this time. Final

adjustment of the bolt actuator tip is

for bolt timing only, and is done after

the completion of rebound work.


Figure H- Shows views of an E/I type rebound lever cam, front bypass bevel bypass bevel corner, front

triangle, and front triangle corner. Always use good light and a magnifying glass when checking or fitting

the rebound cam.

A good measure of care and respect is needed in checking and fitting rebounds- and an extra measure

when it comes to final fitting, adjusting, and tuning the above critical cam surfaces. See figure 211 for D

model rebound data.

Old revolversmiths get an almost reverent look in their eyes when discussing this subject, and tell you, in confidence, that rebounds are "touchy", and that if you are like the rest of us you will probably ruin a few

before you get the hang of fitting them. They are 100% right. Always go very slowly with rebounds, and

double check your steps. Be sure to keep extra replacements in parts stock. Murphy's law tells us that the

part you don't have in back up stock is always the one needed. With rebounds, it couldn't be truer.

One of the biggest mistakes made when a rebound is nearly fit, or is being finally adjusted, is to jump to

conclusions and do one of the following: finish the front of the cam at an angle; over-cut the bypass

bevel; round-oft the front triangle corner at the top; or over-cut the front triangle.

Any one, or a combination, of the above can cause two problems:

1. The bolt actuator tip bypasses too soon (the bolt snaps back up early). 2. The bolt actuator tip slips off and bypasses over the side of the front triangle, rather than over the

front bypass bevel corner (again, bolt snaps back up early).

When a rebound cam is over-cut, there is rarely enough material left to save it. In nearly every case, the

rebound lever will have to be replaced. Also see rebound replacement in Section II, this manual.


Figure 147- Shows a low rebound lever and cam. Clearance

between the top of the rebound cam and the bolt actuator tip

will cause delayed bolt pick up. Without instant bolt pick up,

the cylinder bolt head can slot-drag or jam cylinder rotation.

The bolt head must fully clear the cylinder before the hand

begins rotation.

Figure 148- Shows correct rebound contact at the hammer's

rebound seat, at "A". When the hammer rebounds correctly, the

safety easily moves into position. The rebound is bent so far

upward, at "B", that its hammer seat misses the hammer's

rebound seat. The hammer is too far forward and stops the

safety below the hammer.

If the Rebound Cam is Low

Low rebound cams can be elevated or

repaired by:

1. Bending and arching the lever

body slightly upward. See figure 214. Caution: there are definite

limits to rebound adjustment. See

figure 148.

2. A useful method to keep working

parts original in early collectible

models, is to TIG weld a mild

steel 3/32" bead at the thin, lever

end of the rebound, and then re-

face and refit the lever. Copper

heat sinks are used in this process

to control heat. 3. Or, replace and refit the rebound

lever. See rebound replacement,

Section II.

With slightly low rebounds, refitting

the cylinder bolt head can remove a

small clearance at the rebound cam.

Note: Because refitting low rebounds

is labour intensive and costly, factory

service almost always replaces them.

From the viewpoint of fitting time,

labour charges, and etc., this is a wise judgement call.

Hammer-Safety Interference

The problem with bending, or arching,

the body of a previously fit rebound

lever is that the rebound's hammer seat

surface [which rebounds the hammer]

is also moved upward in the process.

Past a certain point, the hammer seat

can't rebound the hammer enough to clear the upper safety hammer block.

The safety can't slide into position

between the frame and hammer. In

this case, what usually happens is that

the hammer "catches" the safety and

blocks its travel. See figure 148.


Hammer Seat Problems

When a rebound is replaced, or when

refit lower, three problems can come

up having to do with incomplete

fitting:

Trigger Sear Can't Clear The D.A.

Hammer Strut

In this case, the rebound's flat hammer

seat surface is still too long where it

should contact the hammer heel, or

rebound seat. The remedy is to

carefully file the rebound's flat

hammer seat surface back, until the

hammer rebounds closer to the safety,

leaving about .005-.010" safety clearance. Somewhere before this

point, the sear will clear the hammer

strut.

Rebound Drags on Hammer

This is usually caused by an incorrect

hammer seat angle and will show as

drag on the hammer heel/rebound seat.

Adjusting the angle corrects the

problem. See figure 150.

Rebound Rides on Hammer

1. Check by holding the trigger back

and pushing forward on the

hammer [with hammer down].

Check for "hammer bounce"- a

sign that the upper hammer heel is

deflecting the rebound lever.

2. Adjust hammer seat length. See

warning below.

3. Dress bottom hammer seat corner at approximately 45 degrees. See

figs. 149 & 150.

Hammer Catches The Safety

This is caused by a misfit [short]

hammer seat. The rebound must be

replaced.

Warning: The hammer seat must not

be undersized or cut at such an angle that the rebounded hammer position

can no longer provide safety

clearance. Never fit or alter the

hammer's rebound seat.

Figure 149- Shows an I model action with an incorrectly fit

rebound. The flat hammer seat area is correctly cut, but the

bottom bevel is not. The extra corner material rides the

hammer heel and holds it too far back. There isn't enough heel

clearance to allow the rebound to correctly engage the

hammer's rebound seat.

Figure 150- Shows rebound hammer seat and clearance bevel

fitting areas. If the hammer seat is too long, or cut at a wrong

angle, the rebound will ride the hammer. If the bottom

clearance bevel isn't cut deep enough, the rebound will still ride

the hammer; if too deep, the hammer seat can't rebound the

hammer.


Figure 151- Shows the three common rebound lever/hand

surface drag areas. Drag at "1" or "2" is most common, and can

range From slight resistance to enough drag to stick the trigger

and prevent hammer rebound. Drag at "3" is caused by rough

lever bevels and/or a rough or sharp top corner at the hand's

tensioning cam.

Figure 152- Shows rebounds and bolt actuator tips in a cut-

away frame. The tip at "A" stopped returning over its zero

clearance rebound cam after 30 to 40 bolt cycles. This was

caused by bolt/frame seating, and slight flaring at the actuator

tip bottom corner. On the other hand, the rebound at "B" is just

too high.

Other Rebound Related Problems

Sometimes, after a precision job of

rebound replacement, or bolt, rebound,

and hand refitting, the hand/rebound

lever junction will get sticky. Also,

after close fitting, and test firing, the

cylinder bolt can seat-in, making the bolt actuator tip drag or stop returning

over the rebound cam. Although both

can be head scratchers, they are very

easily handled.

Rebound Lever/Hand Drag

If the rebound lever drags inside the

hand, the action will feel slightly

rough. When drag is extreme, the

trigger can stick and will hold the hammer forward. See figure 151.

Look for drag marks and clearance the

appropriate surfaces. Polish contact

areas only as necessary to eliminate

drag. Don't undersize contact surfaces

or alter correct rebound lever fit.

Actuator Tip Stops Returning

When this occurs, the rebound cam

will seem slightly high, again. But,

what has actually happened is that the bolt has seated against the frame's bolt

stop shoulder. This, in turn, lowers the

bolt actuator tip. Also, during seating,

the tip flares slightly at the left corner.

Depress the rebound to test for bolt

seating and bolt actuator tip return. Fit

rebound lower.

While fitting, a way to check for this

problem [and seat the bolt] is to rock

the hammer 50 plus times, causing rapid bolt drop and actuator return. A

half box of test rounds through the

revolver usually produces the same

result.


Figure 153- Shows rebound cam areas in 1 through 5 that must be well fit before the cylinder bolt tang

can be pre-adjusted or final adjusted to correct bolt timing as discussed in 6, 7, and 8.

1. Cam surface- the front bypass edge of the cam must be square and kept at 90 degrees in all D and

E/I models to prevent "slip off" and early bolt drop. 2. Bypass bevel corner- with E/I models, bolt drop may not occur, or may be late, when the bypass

corner of the cam is too far forward. Normally, with E and I models, the front bypass bevel corner

is slightly rounded for correct bolt drop. With smaller D model cams, the bypass corner is not

rounded.

3. Bolt bypass bevel- bolt drop will be early if the front bypass bevel face is too far back, or, with E/I

models, the top corner has been over-rounded.

4. Front bypass angle- this surface is normally adjusted only on D rebounds. If angle is incorrect, the

bolt tip may drag on bypass or be "hard-over-the-cam".

5. Front triangle corner and lower front triangle- the bolt actuator tip can slip off and drop early if the

top outside corner of the front triangle is more than slightly broken. D model top triangle corners

are left square. Incomplete front triangle fitting can cause bolt tip hesitation or failure to escape the

front bypass bevel. If the lower triangle surface is over-cut, the bolt will drop early. 6&7. Bolt tang- the actuator tip will escape at the front triangle and drop the bolt early if the tang isn't

bent inward enough. When adjusted (bent) toward the rebound, the actuator tip tracks a greater

distance down the bypass bevel face before escaping over the front triangle. This delays bolt drop

timing.

8. Bolt actuator tip- edge flanging and/or burrs at the tip can delay bolt drop and also prevent tip

return over the top of the cam. Actuator tips that have been altered, shortened, or worn overly

round will drop early.

Closely examining bolt timing will tell you if any of the above surfaces might need fine adjustment.

Long, and slightly off-time, rebound cams are easily refit. To fine adjust the bolt return area (right side)

and front bypass bevel face, polish with #400 sandcloth. For correct drop timing points, see figures 154 and 155.

When bolt drop timing is slightly late, and/or when the cylinder "throws by", some gunsmiths compensate

by increasing forward double action strut let-out. This procedure is not a recommended remedy. Adjust

bolt drop timing first, and then, only if necessary, adjust the strut to time the hammer. Short, overfit

rebound cams, and worn bolt actuators, drop bolts early and must be replaced.


Figure 154- Shows I model bolt slot leads, and the ideal,

middle 1/3, cylinder bolt drop timing zone. At left, index marks

indicate maximum allowable early and late bolt drop positions.

Always time drop within the ideal zone of the lead. With

original, shorter lead E cylinders, time bolt drop to the approx.

centre of the lead.

Figure 155- Shows D model .38 and .22 cal. bolt timing limits.

When bolt drop is late, [too close to the bolt slot] fast rotation

of the cylinder in rapid fire may cause cylinder throw-by [bolt

can't enter bolt slot in time]. Misfires can result. With early

drop, the bolt head drags against the body of the cylinder.

About Bolt Drop Timing-

Preconditions: Correct bolt height,

head contour, and profile; instant bolt

pick-up; the bolt fully clears the

cylinder before rotation; and all

rebound work completed. Note: The terms "bolt drop" and "bolt drop

timing" are from the original factory

bolt fitting/inspection procedures that

place the revolver on its left side, with

grip frame up. This points the bolt

head down. In this position, the bolt

"picks up" as it retracts into the frame,

and "drops" to engage the cylinder.

E/I Bolt Drop Timing

For best results, time I model cylinder

bolts to drop into the middle 1/3 of the

longer I type cylinder bolt lead.

Ideally, E model bolts drop time best

between 1/3 and 1/2 way into the lead.

See figs. 154 & 155. Remember, the

riding point of the bolt marks the lead.

Because older bolt marks may not

provide a correct current reference,

always directly check bolt drop

position by eye, holding revolver in hand, right side up. If drop timing

requires adjustment, see figure 153.

D Bolt Drop Timing

Bolt drop timing in .38 calibre D

models is ideal at the centre 1/3 of the

cylinder bolt lead, but can be timed

slightly earlier than I models. See

figures 154 and 155. In .22 calibre D

models, bolt drop timing is correct only when inside the middle 1/3 of the

bolt lead. See figure 155. If bolt

timing is early or late, see figure 153.


Figure 156- Shows an I model frame, action, and cylinder. A summary is given

below of checks and fitting work that must be done before the cylinder is reinstalled for top and bottom

hand checks and/or hand fitting:

1. Cylinder work is done, headspace and endplay are correct.

2. Sear and hammer are correct, without push-off; trigger return is smooth.

3. Hand let-out is correct.

4. Forward hand tension is correct.

5. Hand/frame fit is correct, without drag between frame and sideplate.

6. Instant pick-up is present (rebound picks up bolt in time for rotation).

7. Rebound lever rebounds hammer with safety clearance.

8. Rebound's hammer seat does not bind, drag, or "bounce" the hammer.

9. Safety system clears action parts without drag.

10. Bolt drop timing (or pre-timing*) is correct. 11. Bolt actuator tip returns correctly over the rebound cam.

Important note: *When the bottom hand is new, or bottom hand length is unknown bolt drop can be pre-

timed, only. See inset copy and illustration, above. Bolt drop timing can be fine adjusted only after

bottom hand fit is correct.

In this manual, keep in mind that we are discussing D, E, and I models already in use- and earliest to

latest production, as well. Logically, depending on the model being serviced, certain checks and fitting

steps have to be done first, otherwise, one step tends to get in the way of another. It's probable that,

without a correct fitting sequence, parts might have to be refit.

To some revolversmiths already fully qualified in Colt D, E, and I frame action work, it may seem that a few of the above listed fitting steps could be done in a slightly different sequence. If you have a safe,

reliable system, or fitting sequence, that saves time, prevents parts damage, and repeated parts fitting, by

all means use it. However, the top hand cannot be checked or fit without instant bolt drop, and the bottom

hand can't be checked or fit unless bolt drop timing is correct (or very nearly correct).


Figure 156A- Shows a cylinder and ejector ratchet, that, from the viewpoint of fitting a top and bottom

hand, are in reject condition. The ejector has excess sideplay and is loose on the cylinder's ejector guide

pins. Also, one of the guide pins has been chamfered so low that it can no longer hold or align the ejector.

Top and bottom hands cannot be reliably fit when excess sideplay exists. In this case, the ejector star

fingers overlap into the chambers. When shell casings are chambered, the star and ratchet are placed in

one position, and when chambers are empty, the ejector and ratchet float. With this cylinder, the ratchet lugs do not take the same exact position twice. This means there could be no correct top and bottom hand

length unless the ejector star was undersized at the chambers to prevent cartridge case interference, and

each ratchet lug was then individually adjusted to work with the hand. This would amount to a whole lot

of work to attain very poor results. The correct approach is to reject such cylinders, and fit hands only to

ejector/ratchets with near zero sideplay.

Top and Bottom Hand Fitting Caution:

In figures 156 through 168, we are discussing fitting top and bottom hands to ratchets that have been

previously fit. Specifically, the ratchets we're talking about already have been fit to agree with their

cylinders, and have ratchet lugs that have been adjusted before. Presumably, these ratchet lugs are more "equal" than would be the case with new and unfit ratchets.

With new ratchets and/or new cylinder/ratchet assemblies, top and bottom hand fitting requires extra

caution. This is because the new ratchet lugs have not been adjusted yet. As far as the hand is concerned,

the new lugs are, to some extent, "unequal". The problem is that hands can be over-cut [this makes a short

hand] if top and bottom hand are pre-fit to the wrong lug. For this important reason, the procedure for

fitting the top and bottom hand to a new, or unfit, ratchet is a bit different. See hand replacement and

cylinder assembly replacement in Section II.


E/I Top & Bottom Hand Fit

Check E/I Top Hand

Preconditions: fig. 156 & top- bottom

hand caution, 156A.

1. Be sure bolt pivot screw is seated-

if it loosens, bolt timing will

become erratic.

2. Reinstall the cylinder. Centre lock

with latch pin.

3. Check top hand length by rocking

the hammer at each ratchet

position. If the top hand is long,

early rotation can slot-drag, or

bind the bolt. When drag is

present, make sure it isn't at the upper safety and latch pin.

4. When the top hand is long,

carefully reduce the top surface,

without changing the angle, until

the bolt clears the cylinder

without drag. Make sure the bolt

isn't high.

5. A low, or thick ratchet lug will

make a well fit hand seem long,

and bind at that lug position only.

See fig 167.

6. With a short top hand, cylinder rotation is delayed, also, the

bottom hand may bind or drag

against the 2nd ratchet lug.

Caution: Lug bind can be caused,

also, by a long bottom hand.

Always check this before

stretching or replacing the hand.

Check E/I Bottom Hand

1. S.A. cock the hammer very slowly, watching the bottom

hand. It should pick up the 2nd

ratchet lug just at, or slightly

before, the half rotation point.

The bottom hand must be long

enough to carry the cylinder to

positive index. If short, the hand

will have to be stretched, or

replaced. When long, the bottom

hand can prevent single action

sear overhaul.

Figure 157- Shows correct E/I hand function. The top hand, at

"A", begins cylinder rotation. The bottom hand picks up the

second ratchet lug about half way between the chambers, and

supports rotation. At "B", the top hand clears the ratchet at

about 95% rotation. The bottom hand carries the cylinder to

positive bolt index.

Figure 158- Shows a well fit E/I bottom hand. After bolt index,

and the sear/hammer notch is engaged, the bottom hand will

just clear the second lug by the amount of sear overhaul. At

trigger squeeze, the bottom hand lifts the second lug just

enough to remove bolt/slot/lug clearance and becomes the

second cylinder lock.


Figure 159- Shows an I model hand and ratchet. In this

example, the top hand is long and tries to rotate the cylinder

before the bolt fully clears the slot. The bolt slot-drags. If the

hand was slightly longer, the bolt would jam rotation. A high

bolt head or low rebound can also cause this problem. Correct

both before hand work.

Figure 160- Shows a short I bottom hand. This hand can't rotate

the cylinder quite enough to index the bolt. If the cylinder is

not aligned, a potentially dangerous condition, the forcing cone

is loaded unequally, bullets are upset, and pressure curves

affected. Most short hands can be stretched and refit on a one

time basis.

Check E/I Bottom Hand,

Continued-

2. If the bottom hand is just slightly

long, it may cause the S.A. sear to

hold low and drag against, or

bump, the hammer toe on S.A. release. And if much longer, the

cylinder can ratchet drag or bind

just at half rotation.

3. When the cause of ratchet bind is

in question, recheck for a short

top hand before adjusting the

bottom hand. Note: A long

bottom hand can also cause rough

SA sear release, and when very

long, prevent S.A. sear overhaul.

4. Carefully file, and then stone, the bottom hand until the bottom

hand rotates the cylinder to full,

positive bolt index somewhat

before single action sear

engagement in the hammer's

cocking notch. Do not change the

original hand engagement surface

angles.

5. The bottom hand should be left

just a bit long for bench seating.

[S.A. overhaul will be slightly

stiff.] The reason for extra length is: after test firing, the hand and

ratchet will seat. The hand that

was originally fit at the bench just

to perfect length then winds up

slightly on the short side. See

figure 169 hand/ratchet seating,

and fig. 164, short hand warning.

Warning: Bottom hand/lug fit and

bolt index must be detail checked

at all six ratchet lug positions.

Otherwise, a well fit bottom hand may not be able to rotate the

cylinder to full bolt index against

an over-cut or misfit ratchet lug.

Damaged, misfit ratchets or

cylinder/ratchet assemblies must

be replaced.


D Top & Bottom Hand Fit

Check D Top Hand

Preconditions are same as E/I. See fig.

156 and top- bottom hand caution,

156A.

1. Be sure bolt pivot screw is seated.

If it loosens, bolt timing will

become erratic.

2. Reinstall the cylinder. Centre lock

with latch pin.

3. Check top hand length by rocking

the hammer at each ratchet

position. If the top hand is long,

early rotation can drag or bind the

bolt head. A low ratchet lug will make a closely fit hand seem

long, and bind at that lug position

only. See figure 168. When drag

is present, make sure the safety

isn't dragging at the back of the

latch pin.

4. If the top hand is long, carefully

reduce top surface, without

changing angle, until the bolt will

just clear the cylinder without

drag. If there is any question

about bolt drag, first recheck bolt height before fitting hand.

5. A short top hand, if combined

with a low bolt or rebound, may

allow the bolt to clear without

drag. But, with the cylinder's

rotation delayed, the bottom hand

may bind or drag against the 2nd

ratchet lug. Caution: Bind also

can be caused by a too long

bottom hand. For this reason,

always check bottom hand length before stretching or replacing

hand.

Check D Bottom Hand

1. SA cock the hammer very slowly,

watching the bottom hand. It

should first pick up the 2nd

ratchet lug just at, or slightly

before the approx. 90% cylinder

rotation point.

Figure 161- Shows correct D hand function. At "A", the top

hand picks up the ratchet lug and begins rotation. The bottom

hand engages the next lug at about 90% rotation and carries the

cylinder to bolt index. At "B", the bottom hand becomes the

second cylinder lock, maintaining positive lock position during

the firing cycle.

Figure 162- Shows a well fit D bottom hand. As with E/I

hands, after bolt index and S.A. sear/hammer notch

engagement, the bottom hand will just clear the second lug by

the amount the hammer toe needs to overhaul the sear. On

trigger squeeze, the bottom hand lifts the 2nd lug, eliminating

bolt/slot/lug clearance.


Figure 163- Shows an I hammer toe dragging the S.A. sear on

hammer release. Sear-hammer toe bumping or drag is nearly

always caused by a long D, or E/I bottom hand, and less often

by a long sear extension or a rough, unbevelled hammer toe.

Pre-checking both sear and hammer toe can prevent

overcutting the bottom hand.

Figure 164- Shows a D model with a short hand problem. Here,

the hammer's single action cocking notch is on the verge of

overhauling the single action sear, but the short bottom hand

can't fully rotate the cylinder to positive bolt index before the

sear is overhauled. This hand must be stretched and refit, or

replaced.

D Bottom Hand, Continued-

The bottom hand must be fit long

enough to carry the cylinder to

positive index. If short, the hand will

have to be stretched, or replaced. See

figures 161 through 164.

2. If the bottom hand is just slightly

long, it may cause the SA sear to

hold low, feel rough, or drag

against the hammer toe on S.A.

release. Note: When very long, a

bottom hand can also prevent

S.A. sear point overhaul.

3. Carefully file, and then stone, the

bottom hand until the bottom

hand rotates the cylinder to full, positive bolt index somewhat

before single action sear-cocking

notch engagement. Depending on

let out and angle, D bottom hands

may require a slight angle

adjustment for correct ratchet lug

engagement.

4. The bottom hand should be left

just a bit long for bench seating.

[When long, S.A. overhaul will be

stiff.] The reason for this is: when

bottom hands are bench fit to what seems a perfect length,

sometimes, after test firing, the

hand and ratchet will seat and

wind up slightly on the short side.

See figure 164 for short hand

warning, and 170 for hand/ratchet

seating.

Warning: Bottom hand/lug fit and bolt

index must be detail checked at all six

ratchet lug positions. Otherwise a correct bottom hand may not be able

to rotate the cylinder to full bolt index

against an over-cut or misfit ratchet

lug. Replace damaged, misfit ratchets

or cylinder/ratchet assemblies.


Stretch Short D or E/I Hand

When hands are found short from long

wear, slight over- fitting, or from

hand-ratchet seating, overall length

can be increased, in most cases, by

peening and stretching the hand. See figs. 165 and 166. Factory service

procedures do not call for annealing

the hand or stretch area inside the

rebound slot, before or after peening.

Although some gunsmiths stretch

hands a second time, the practice is

not recommended, since work

hardening and crack potential are

increased with peening. There are

several stretching methods, including

the direct peening of the stretch area with a cross-peen hammer, but the

best approach is to:

1. Estimate stretch length that is

needed by inserting a feeler gauge

strip between the bottom hand

and ratchet.

2. Measure hand length. Add stretch

length for new overall refitting

size.

3. Place hand, outside down, on a

solid steel bench block. Block surface must be 100% flat and

smooth. See fig. 166.

4. Install stretching punch inside the

hand's rebound slot. Then, strike

moderately with an 8 ounce ball

peen. Change punch position and

re-measure with each strike.

5. Stretch hand slightly over actual

length needed to allow for final

fitting and seating. Don't increase

overall hand length by more than .010".

6. Before fitting, always closely

inspect the hand for possible

beginning cracks.

7. Then, refit the hand. See hand

fitting sections, and also figures

169 and 170.

Figure 165- Shows the thin peening area inside the hand's

rebound slot. Hands are peened only on a one time basis.

Typical stretch requirement is about .002"-.005"; with stretch

limit at .010". Depending on hand thickness, previous bending,

etc., there is always the risk that a hand may work harden or

crack, and have to be replaced.

Figure 166- Shows basic tooling for stretching the hand- a flat

peening/stretching punch and polished steel bench block. The

punch is ground from a cold chisel. The face is stoned smooth.

Increased contact area expands and stretches more of the hand

surface at one time, with less work hardening, decreasing crack

potential.


Figure 167- Shows E/I model ratchet lugs and fitting areas.

When a lug is rough, too thick or slightly off index, its position

is usually low compared to the other lugs. This lug may cause

the cylinder bolt to slot-drag or even jam the cylinder. With a

low lug, the hand will seem long, but only at the lug, or lugs, in

question.

Figure 168- Shows D model ratchet lugs and lug fitting areas.

Since the D top hand does not bypass, this ratchet has no

bypass clearance bevel. With fewer set-up and machining steps

involved, lug position is seldom off index. Fine cut 4" barrette

files and fine flex stones are the best tools for D and E/I ratchet

lug adjustment.

About Ratchet Fitting-

If the top hand is still a bit tall, the bolt

will be draggy, and the cylinder will

tend to jump into rotation just as the

bolt clears. Further light top hand

fitting is required. If the bolt is still draggy at one cylinder lug, that lug

may be low. Confirm this possibility

by engaging and locking that lug with

the bottom hand.

Low or Thick Ratchet Lug

1. Mark the possible low lug with a

felt tip pen.

2. Cycle check and re-mark the

questionable lug several times to eliminate error.

3. Inspect the marked lug for nicks,

dents, or burrs. With the tip of a

fine flex stone, lightly dress the

lug's hand engagement surface .

4. Then, recheck bottom hand/lug

engagement.

5. If only the marked lug binds lock-

up, causes sear drag, etc., file a

very small amount from the lug

surface with a fine cut barrette

file. Keep the lug surface flat and at the original factory angle.

6. Lightly dress the filed area and

then recheck lug function with

bottom hand.

7. If necessary, repeat above steps 4,

5, and 6.

Over-fit Ratchet Lugs

An over-fit lug is too short to allow

the hand to carry the cylinder to bolt index. This is a potentially unsafe

condition. Remedies are:

1. If over-fit is slight, stretch or

replace hand and then

individually fit each lug.

2. If over-fit is more than slight,

replace the ratchet and cylinder

assembly.

Caution: Recheck bolt index timing before ratchet work.


Bottom Hand Seating

Some amount of bottom hand seating

always occurs after fitting, and during

test firing. When ratchets are new, or

have been newly adjusted, lug

surfaces also seat during firing. This seating adds to bottom hand seating,

creating a condition called "bottom

hand short". See figure 169.

Seating is most evident when, after a

half box, or more, of test ammunition,

the bottom hand that was just right at

the bench is then slightly short.

Usually, little will be wrong with the

hand fitting job, except that no

allowance was made for surface

seating.

Hand, Hand/Ratchet Seating

The best ways to seat hands and

ratchets involve fitting the bottom

hand just slightly long. You can then

either:

Seat by Test Firing Method-

1. Fully assemble the revolver,

function check, and then test fire each chamber four or five times.

2. If bottom hand still seems a bit

long, disassemble, stone lightly,

and repeat test fire.

Seat by Impact Method-

1. Install the sideplate.

2. Place the trigger guard on padded

bench top.

3. S.A. cock the action; let hammer down; pull trigger back; hold

hand hard against the ratchet lug;

then sharply rap the top back of

the frame with a rawhide mallet.

4. Impact at all six chamber

positions. Repeat as needed.

5. Recheck hand function.

Don't skip hand fitting steps. Never fit

the hand slightly on the long side, then

leave final seating to the owner.

Figure 169- Shows ratchet areas where the lug undersurfaces

seat from bottom hand contact. The bottom hand engagement

will also seat. Machine and file fitting marks on both contact

surfaces are flattened in seating, and slightly undersized as a

result. Initially, bottom hands should be fit a bit long, for this

reason.

Figure 170- Shows the bench hand/ratchet seating method,

worked out by revolversmith Al Sholes. With this system, the

bottom hand is fit slightly long and held hard against the

ratchet lug at each chamber position. Then, the top of the frame

is rapped with a rawhide mallet. This is the bench equivalent of

seating by test firing.


Figure 171- Shows dummy .38 shells installed for shell head

clearance check. The front corner of the top hand, at "1", is

filed and polished for shell clearance. The forward edge, at "2",

is lightly dressed when it interferes with or drags shell heads.

The inside hand surface is polished, at "3", to eliminate drag at back of the ratchet.

Figure 172- Shows hand's shell head clearance fitting areas at

"A", and smooth action fitting areas at "B". Slight hand

irregularity, after peening, may cause drag or bind at sideplate

or rebound lever. After peening, check and polish the rebound

recess and the outside of the hand. Break sharp edges and

bottom hand corner.

Hand/Shell Head Clearance

At minimum headspace and cylinder

endplay, .38/.357 shell head clearance

averages just at .005-.006". With small

variations in hand let-out and wear at

the frame's hand post surface, the front corner of the top hand and/or the front

area just below the bottom hand may

drag or bind against shell heads during

cylinder rotation. A small amount of

additional hand fitting is necessary to

provide clearance between the front of

the hand and chambered shell cases

during cylinder rotation. See figures

171 and 172.

1. Install three fired [empty] shell cases in cylinder.

2. Slowly S.A. cock hammer.

3. Check for shell contact at top

hand point, and at front surface

below bottom hand.

4. Bevel and polish corner of top

hand as needed for clearance. See

figure 171.

1. 5. File and polish shell head

contact area below bottom

hand. See figs. 171 and 172.

Polishing the Hand for Smooth

Action

After peening and shell head clearance

work, some areas of the hand may not

be as smooth as they should be.

1. Closely inspect rebound recess

and file any raised material left

from peening.

2. Level any peening marks on the outside of the hand.

3. If not already done, lightly break

the front corner of the bottom

hand.

4. Then, lightly chamfer all sharp

edges and top corners that might

contact or drag the frame and

sideplate.


Check D, E and I Mainspring

The easily identified #56090 D model

mainspring is somewhat smaller than

the #57122 mainspring used in I

model production. The #57122 I

mainspring replaces the much earlier #50359 E mainspring. Closely inspect

the arms and ends of the mainspring.

If the mainspring is altered by

grinding, filing narrower or thinner,

has been twisted, has excessive

recurve, or shows evidence of other

damage, do not use it- replace the

spring. Weak or incorrectly tensioned

mainsprings can cause light, possibly

unsafe, single action trigger pull,

misfires, poor rebound function, and trigger return problems, as well.

Factory Specified SA Pull-

Model Min. Max.

D/22 3.0 lbs 5.0 lbs

D/32 3.0 lbs 5.0 lbs

D/38 3.0 lbs *5.0 lbs

E/32 3.0 lbs 4.5 lbs

E/38 3.0 lbs 4.5 lbs

I/38 2.5 lbs 4.5 lbs

I/357 2.5 lbs 4.5 lbs

*Factory specified maximum pull for late Agent is 7 lbs.

If overly strong, or poorly adjusted,

the mainspring will produce heavy,

increased S.A. and D.A. trigger pull.

See figs. 173, 174, and 177.

Set mainspring tension to not more

than factory specified maximum D.A.

trigger pull:

Factory Maximum DA Pull-

D/22 14 lbs max.

D/32 14 lbs max.

D/38 14 lbs max.

E/32 14 lbs max.

E/38 14 lbs max.

I/38 12 lbs max.

I/357 12 lbs max.

Figure 173- Shows an I model mainspring and tensioning

point. D and E/I mainsprings tension by bending upward at

approx. 7/8" to 1" from the middle of the stirrup seat. The

factory I model mainspring clamp, shown below, is used

primarily in rebound adjustment, but can be used as a

mainspring installation tool, as well.

Figure 174- Shows using a small straight shank drift to "back

bend" and adjust an over-strong mainspring. The hammer is

S.A. cocked with the drift installed inside the spring. This puts

a slight recurve in the mainspring. Drift shank dia. determines

recurve and the amount spring tension is reduced; increase

diameter as needed.


Figure 175- Shows front and rear cylinder latch fitting areas,

above. Below, the latch spring, guide, and spring tunnel are

checked in the sideplate. The latch spring must not bind or drag

inside the spring tunnel; otherwise, full spring pressure will not

be available to centre- lock the latch pin in the cylinder.

Figure 176- Shows sideplate being reinstalled in the frame. The

latch, latch spring, and guide are pre-installed in the sideplate.

The latch is held back just enough to line it up with the latch

pin inside the frame. Once the latch pin is engaged, the

sideplate is started, pushed down, and then bottomed in the

frame.

Check Cylinder Latch, Latch

Spring, and Guide

Before the sideplate can be installed in

the frame, the latch, latch spring, and

guide must be checked for proper

sideplate fit. The latch spring must supply correct forward latch pin

tension.

1. The latch spring must be full

length and full strength. To be

sure, check it against a new

replacement part.

2. The spring tunnel inside the

sideplate must be clean, and must

not bind the spring. See figure

175. 3. If the spring binds in the tunnel,

ream just enough to allow free

spring movement.

4. Check cylinder latch fit in

sideplate slots.

5. If the latch drags, stone the

bottom and/or guides for sideplate

clearance.

6. If an early style latch is loose,

carefully peen latch slot guides to

improve fit.

7. 7. With loose late style latches, replace nylon insert.

Install Sideplate

Prevent unnecessary frame- sideplate

edge marking and/ or edge damage by

installing the sideplate as follows:

1. Inspect and lightly stone any

nicks found at the edges of the

sideplate. 2. Hold the sideplate straight over

the frame. Don't try to start it on

an angle.

3. Push the latch back just enough to

align it with the latch pin inside

the frame.

4. Once the latch has picked up the

latch crosspin, lower the sideplate

in the frame.

5. Push the sideplate straight down

until it bottoms. 6. Install sideplate screws.


Figure 177- Shows testing single action trigger pull using the

NRA type weight method. With trigger pull below 6 to 7 lbs.,

this system is more consistent than others. By adding and

subtracting fractional weights, it can be used as a sear and

mainspring adjusting aid. For best results when single action

trigger pull is above 7 lbs., or when checking any double action pull, I suggest using a precision pull-weight recording trigger

scale [see inset below].

Test SA and DA Trigger Pull

Both single and double action trigger

pull must be checked after action

work, and when mainspring tensioning

adjustments are made; and again at

final test after the revolver has been fully assembled.

See page 121 for factory SA and DA

pull specifications, and figures 173

and 174 for mainspring adjustments.

Final sear point engagement position,

squareness of the sear point, and

spring tension primarily determine

S.A. pull in D, E, and I model actions.

However, action drag, being cumulative, always adds resistance to

trigger pull.

D, E, and I model D.A. pull is mostly

determined by mainspring tension but

added to by factors such as: a rough

D.A. strut, hand drag, etc.

When mainspring tension is adjusted

to reduce double action trigger pull,

there are two limiting conditions:

1. Single action trigger pull must not

be reduced below factory min.

specifications.

2. Hammer fall should not be

lightened to the extent that

misfires result.

Remember, the definition of a safe

trigger is: DA and SA trigger pull is

within factory specification and the

hammer does not push off the sear.

Final Push-Off Test

The final push-off test is done after the

sideplate has been installed. The

hammer is S.A. cocked, with the sear

point fully engaged in the hammer's

S.A. cocking notch.

The hammer must not push off when

pushed from either side or from the rear.


Figure 178- Shows a Colt Python set up for test firing in a Ransom Master Series Machine Rest.

Individual grip inserts are used to mount the specific revolver model to the main body of the rest. After

firing, the revolver and upper rest are returned to original firing position by depressing the return lever

next to the elevation screw. The basic Master Series Rest is adjustable for elevation. Optional windage

base, shown above, provides windage adjustment. -Photo courtesy Ransom International Corp.

A good machine rest is a valuable aid to the revolversmith in isolating and solving cylinder,

cylinder/barrel alignment, timing, and sight related problems. Machine rests eliminate both guess work

and hand held error factors- and make problem correction easier.

After all safety and function checks have been completed- install the revolver securely in the rest. Then

make the following firing tests:

1. Using factory ammunition, paper target test for consistent points of impact at a range of 50 feet or

more. If groups are not satisfactory, impact pattern is dispersed, or keyhole bullet markings are

found, see sections on barrel work, forcing cones, and plug gauge [range rod] checking, in Section II.

2. Check cylinder for smooth, normal rotation with each round, and for correct shell case ejection after firing. Check for correct firing pin/primer indentations.

3. Revolvers with adjustable sights- adjust windage and elevation settings to centre bullet impact on the

target. If adjusting screws are stuck or resistant, and/or the sight blade won't move or shows signs of

damage, etc., see adjustable sights, Section II. Note: The rear sight blade notch should be at

approximate centre of the sight leaf body after zeroing adjustment.


Summing It Up

In this first section, we have covered the majority of shop inspection and general fitting work that could

come across a revolversmith's bench. The non-gunsmith may find the information somewhat tedious, or

of limited interest. But the fact is that, as a revolversmith, you will see revolvers of every age and possible

level of condition: from those needing a simple cleaning to those requiring complete rebuilding. And,

from time to time, you will even be asked to repair revolvers that are beyond reasonable repair.

For safety and liability reasons- always operate from a "worst condition" scenario so that nothing is

overlooked. Even though you may not have included the cost of a detailed overall inspection, including

safety system parts and operation- spend the time and do it just the same. It may be that your work order

notes and cautionary advice to your customer could protect both of you from harm.

No matter what work a revolver may require, do it thoroughly and then recheck it. While working,

carefully protect the finish on your customer's gun. Finish damage is evidence of poor craftsmanship.

Common sense, a clean work bench, and careful handling will reduce finish damage to near zero.

Now and then, a beginning revolversmith may find himself in doubt as to some aspect of the job at hand. When this happens, have the problem, or your work, checked by a senior Colt qualified gunsmith. Don't

fog the problem over and send it on its way, as if magically corrected. It is the smart man who knows

when he has a problem- but it's the wise revolversmith who gets a second opinion, when needed. The

even wiser shop supervisor watches for those who can be depended upon to do things safely and well.

In this time of impossible product liability and, for many, nearly unobtainable insurance, the

revolversmith has to be careful to the point of the ridiculous. There is no such thing as too much caution.

We all owe it to each other to preserve our industry, and careful workmanship is a good place to start.

Good training, thoughtful customer advice, and competent safety instruction will also help a lot.


Figure S2- Shows a destroyed Python. The forward half of the barrel was filled with jacketed lead slugs to

the point shown. The barrel ruptured where the last bullet impacted the obstruction.

While it's difficult to know the real facts, one thing is clear- the owner was a reloader, and was firing his

own creations. It appears that the first five bullets were driven into the bore by magnum primers, only,

and- by all indications, the last by a double magnum charge.

Just for the sake of discussion: let's say that a reloading book lists a load at 43,500 PSI (copper) based on

eight grains of a given powder. If, for example, 5% more of the same powder (or only .4 grain) jumps

chamber pressure past the industry maximum for the .357 magnum case- it seems that only a fool would load that extra .4 grain. This being the case, what on earth do you call a fellow who follows five empties

with a double magnum charge?


Figure S3- Shows a 2" Cobra (alloy frame) destroyed by firing what, at first, appeared to be a single

(restricted use) +P+ round. And it may have been. But, this owner was also a reloader. Although he

insisted the round fired was not a reload, he was seen chambering this, and other rounds, from a box of

obviously reloaded ammunition. A wise rangemaster confiscated several of the rounds, just in case the

"accident" turned out to be a "sue everybody" event.

How would you like to be standing at the firing line next to the kind of character who does this? It's

enough to ruin your sight picture, isn't it?


Figure S4- Shows further examples of the laws of physics in action. These items are shown, not to

belabour the point that revolvers can be damaged, but to stress the fact that there are people who actually

do this kind of thing- and sometimes more than once. These same people have a hard time being

responsible for their actions. Since it's impossible to know who these characters are until after the fact, the revolversmith and gunsmith must be very careful in both work done and records kept. People who destroy

firearms have been known to sue the manufacturer, the gunsmith, the rangemaster, and the horse he rode

in on, over mishaps they, alone, caused.


TROUBLESHOOTING GUIDE

Half-sectioned .357 magnum shell case and stainless steel Python crane/cylinder assembly show chamber, ejector rod, and ejector/ratchet details.


Figure J- Shows a right side view of a cutaway Python revolver used for gunsmith training. This side

shows rebound lever/cylinder bolt functions, and inertial firing pin operation.


Figure K- Shows the left side, and a three quarter view of a cutaway Python gunsmith training revolver.

The left side shows double and single action operation, barrel threads, forcing cone details, crane

operation, and cylinder/ejector rod function.

The Colt DA Revolvers, Section I 132 WHERE? WHAT IS IT? CHECK FOR: REMARK: Barrel Heavy leading Lead velocity too high? Check loading Barrel Heavy leading Velocity O.K.? Check bullet lube Barrel Heavy leading Lube O.K.? Check bullet diameter Barrel Leading Soft alloy? Adjust alloy Barrel Leading Soft alloy? Adjust lubricant Barrel Leading Soft alloy? Use Lewis Lead Remover Barrel Rusty Rust inside? Replace barrel

Barrel Bulged Stuck slugs? Replace barrel Barrel Slug stuck Barrel O.K.? Replace if swelled Barrel Inaccurate Crown damaged? Recut crown Barrel Inaccurate Bore irregular? Plug gauge test Barrel Inaccurate Bore oversize? Slug and measure barrel Barrel Inaccurate Forcing cone problem? Gauge test cone mouth Barrel Inaccurate Damaged forcing cone? Replace barrel Barrel Inaccurate Cylinder aligned? Thimble/plug gauge check

Barrel Loose in frame Shoulder misfit? Re-qualify barrel Barrel Loose in frame Thread problem? Replace barrel Barrel Loose in frame Frame cracked? Replace frame Barrel Threads damaged Frame threads O.K.? Replace barrel Barrel Not straight Crane/cylinder O.K? Replace barrel Barrel Visibly dented, bent Frame O.K? Replace barrel Barrel Crown damage Bore O.K? Recut crown and lap Barrel Forcing cone eroded Light flame erosion? Requal. barrel, re-cut cone Barrel Forcing cone eroded Medium erosion? Replace barrel

Barrel Forcing cone mis-cut Bbl. not re-qualified? Requal. barrel, re-cut cone Barrel Forcing cone mis-cut Bbl. already re-qualified? Replace barrel Barrel Forcing cone cracked Heavy loads? Replace barrel Barrel Forcing cone leaded Hot lead loads? Use Lewis Lead Remover Barrel Rear face crooked Gap acceptable? True barrel face Barrel Rear face crooked Gap near maximum? Re-qualify barrel, re-face, etc. Barrel Cylinder gap small Headspace open? Stretch collar/adj. headspace Barrel Cylinder gap small Collar/headspace O.K? Adjust barrel face

Barrel Spits lead Crane/cylinder aligned? See crane/cyl. alignment Barrel Spits lead Excess cylinder gap? Check cylinder endplay Barrel Spits lead Excess cylinder gap? Re-qualify barrel Cylinder Loose (early style) Crane moves front-back? Crane/detent worn

Cylinder Loose Cylinder endplay? Check collar/ratchet Cylinder Loose Cylinder endplay? Adjust collar, headspace Cylinder Loose Cylinder endplay? Replace cylinder/ratchet Cylinder Loose Sideplay on crane? Cylinder O.K.?- replace crane Cylinder Loose Sideplay on crane? Crane O.K.?- replace cylinder Cylinder Loose Crane stem loose? Frame O.K.?- replace crane Cylinder Loose Crane stem loose? Crane O.K.?- replace frame Cylinder Rusty Pitted? Replace cylinder

Cylinder Won't open Latch resistant? Check latch, oil stuck/rusted Cylinder Hard opening Ejector rod bent/drags? Check, straighten rod Cylinder Hard open/close Hand let out too far? Replace hand Cylinder Hard open/close Ratchet damaged? Replace ratchet Cylinder Rotation stiff Hand binds shell heads? Adjust hand for clearance Cylinder Rotation stiff Recoil plate high? Is recoil plate seated? Cylinder Rotation stiff Plate seated O.K? Level recoil plate, high spots/burrs Cylinder Rotation stiff Dried oil residue? Detail clean

Cylinder Rotates hard Ejector rod bent? Straighten/replace rod Cylinder Rotates hard Fired shell head drag? Check minimum headspace Cylinder Won't rotate No instant bolt pick-up? Fit rebound and check bolt tang Cylinder Won't rotate Instant pick-up O.K? Check bolt head height Cylinder Won't rotate Instant pick-up O.K? Check top hand long Cylinder Won't rotate Hand skips by? Adjust hand let out Cylinder Won't rotate Hand backs up? Increase let out. Cylinder Won't rotate Hand skips/deflects? Adjust tensioning cam angle

Cylinder Binds Hand binds shell heads? Adjust hand Cylinder Binds Top hand short? Stretch or replace hand Cylinder Binds Bottom hand long? Fit bottom hand


WHERE? WHAT IS IT? CHECK FOR REMARK Cylinder DA mid-rotation hard Top hand long? Adjust top hand Cylinder End of rotation hard Bottom hand long? Fit bottom hand Cylinder End of rotation hard Sear extension long? Refit sear/hand Cylinder Rotates past lock Bolt timing late? Check bolt/rebound Cylinder Rot. short at hammer drop D.A. strut tip short? Replace strut Cylinder Rot .short at hammer drop Strut let out short? Adjust let-out Cylinder Rot. short at hammer drop Bottom hand short? Stretch/replace hand

Cylinder Shaves lead Crane bent? Align crane Cylinder Shaves lead Clearance excessive? Re-qualify barrel Cylinder Shaves lead Yoke & clearance O.K? Check forcing cone Cylinder Shaves lead Bolt worn/thin? Replace bolt Cylinder Shaves lead Bolt slots loose? Replace cylinder Cylinder Shaves lead Cone mouth undersize? Recut forcing cone Cylinder Hits closing (old style) Crane bearing wear? Install bearing washer Cylinder Hits on closing Tight endplay? Fit ratchet

Cylinder Hits on closing Long top handpoint? Dress top hand point Ejector Rod sticks Rod bent? Check/straighten rod Ejector Rod sticks Dried oil, dirt in crane? Clean crane, rod stem, etc. Ejector Hard eject Rod bent? Check/straighten rod

Ejector Hard eject Eject, star drags cyl.? Refit star fingers Ejector Hard eject Guide pins rough? Dress/chamfer pin heads Ejector Hard eject Eject. star overlap? Burnish fingers/chambers Ejector Star sticks Guide pins nicked? Chamfer pins Ejector Star sticks Burrs, nicks? Dress star fingers Ejector Rough Rough stem spline? Dress or replace rod Ejector Star loose on pins Overchamfered pins? Replace cylinder Ejector Star loose on pins Oversized pin holes? Replace star/cylinder

Ejector Won't return Spring wrong/missing? Replace spring Ejector Won't return Spring over flange? Crimp end of spring Cyl. Bolt Sticks In frame window? Fit/deburr window Cyl. Bolt Sticks In cylinder slot? Check slot for burrs

Cyl. Bolt Sticks In cylinder slots? Check stop head width Cyl. Bolt Delayed pick-up Rebound low? Adjust rebound Cyl. Bolt Slot drags Bolt head too high? Adjust bolt head Cyl. Bolt Slot drags Top hand tall? Adjust top hand Cyl. Bolt Slot drags "Unequal" ratchet lug? Adjust hand/lugs Cyl. Bolt Snaps back early Bolt timing problem? Adjust bolt tang Cyl. Bolt Snaps back early Misfit rebound? Replace rebound Cyl. Bolt Snaps back early Altered bolt actuator? Replace bolt

Cyl. Bolt Drops late Too much inward bend? Adjust bolt tang Cyl. Bolt Drops late Cam bypass bevel long? Adjust bevel Cyl. Bolt Drops late E/I cam not rounded? Slightly round front of cam Cyl. Bolt Hard over cam E/I cam slightly long? Lightly stone front bypass bevel Cyl. Bolt Hard over cam D cam angle incorrect? Change angle (don't alter cam) Cyl. Bolt Won't return Cam too high? Adjust rebound Cyl. Bolt Won't return Cam height O.K? Polish front triangle Cyl. Bolt Won't return Bolt tip burrs? Carefully deburr

Cyl. Bolt Won't return Tang bend incorrect? Adjust bolt tang Cyl. Bolt Function erratic Loose on pivot screw? Adjust to snug pivot fit Cyl. Bolt Falls back Spring problem? Replace spring Cyl. Bolt Loose in cylinder Head worn? Replace bolt Cyl. Bolt Loose in cylinder Bolt head O.K? Replace cylinder Cyl. Bolt Won't hold lock Bolt head low? Adjust head higher Cyl. Bolt Won't hold lock Head height O.K? Re-contour/profile head Cyl. Bolt Allows back-roll Head overchamfered? Refit bolt head Trigger No return/sticky Frame/sideplate bind? Polish left bearing surface Trigger No return/sticky Hand/frame bind? Refit hand Trigger No return/sticky Hand/sideplate drag? Refit hand Trigger No return/sticky Rebound drags hand? Dress lever end and side

Trigger No return/sticky Hand's slot rough? Polish hand's rebound slot Trigger No return/sticky Reb. drags sideplate? Polish side of rebound


WHERE WHAT IS IT? CHECK FOR: REMARK: Trigger No return/sticky Rebound drags hammer? Polish inside lever extension Trigger No return/sticky Rebound drags hammer? Refit rebound's hammer seat Trigger No return/sticky Reb. rides hammer heel? Complete rebound fitting Trigger No return/sticky Hand backs up rebound? Adjust hand let out Trigger Stiff Low sear point? Adjust sear point position Trigger Too light High sear point? Adjust sear point position Trigger Heavy Sear point O.K? Adjust mainspring

Trigger Light Sear point O.K? Adjust mainspring Trigger Creeps Stiff mainspring? Adjust tension Trigger Creeps Mis-cut sear? Adjust sear/replace trigger Trigger Creeps Sear O.K? Check hammer notch/repl. hammer Trigger Hesitates Action drag? Eliminate drag Trigger S.A. overhaul stiff Long sear point? Adjust sear Trigger S.A. overhaul stiff Long bottom hand? Refit bottom hand Trigger S.A. overhaul rough Rough under sear ext.? Polish surface

Trigger S.A. overhaul rough Rough top hammer toe? Polish top surface Trigger S.A. overhaul rough Frame stops hammer? Clearance frame Trigger D.A. rough Strut tip rough? Point and polish strut Trigger D.A. rough Trigger pick-up rough? Polish top of sear ext. Trigger D.A. heavy Stiff mainspring? Adjust tension Trigger Hits D.A. strut Sear point long? Adjust sear point Trigger Hits D.A. strut Sear point O.K? Replace D.A. strut Trigger E/I link pin drags Link pin high? Seat link pin

Trigger E/I link pin drags Pin seated O.K? Dress link pin head Trigger Sear erratic Loose on pin? Check against new pin Trigger Sear erratic Pin undersize? Replace trigger pin Trigger Sear erratic Frame pin O.K? Replace trigger E/I Safety Link pins drag Pin heads high? Dress to flush with lever E/I Safety Upper link pin catches Pin head high? Dress to flush with lever E/I Safety Upper link pin catches Pin head flush? Undercut/chamfer hammer skirt Safety Lever drags hammer Lever high at boss? Resurface with boss hub cutter Safety Drags in frame recess Burrs, nicks? Deburr, do not oversize recess Safety Drags latch pin Burrs or pin high? Deburr frame, dress latch pin Safety Catches hammer Rebound overfit? Replace rebound lever Safety Catches hammer Hammer altered? Replace hammer

Safety Misses hammer Wrong upper safety? Replace safety assembly Safety Missing All or part not there? Replace safety assembly Hand Forward at rest Over let-out? Dress top hand tip Hand Forward at rest Excess let-out? Replace hand

Hand Backs up/deflects Frame post thick? Increase let out Hand Skips ratchet Otherwise O.K? Increase let out Hand Lazy/skips Forward tension weak? Adjust hand cam Hand Sticks Bend incorrect? Adjust bend Hand Sticks Too thick? File, polish outside Hand Sticks Frame burrs? Lightly dress frame Hand Sticks Sideplate slot burrs? Dress sideplate slot Hand Sticks Pivot pin rough? Carefully dress pin

Hand Sticks Rebound slot rough? Stone/polish slot Top Hand Short Binds at 1/2 DA rotation? Adjust top hand Top Hand Short Binds ratchet? Stretch/replace hand Top Hand Long Cylinder jams Fit top hand Top Hand Long Bolt slot drags Fit top hand Top Hand Long One chamber drags? Fit long ratchet lug Top Hand Catches ratchet Extends past frame? Stone tip Bot. Hand Short Cylinder doesn't lock? Stretch/replace hand Bot. Hand Long Action won't S.A. cock? Adjust bottom hand

Bot. Hand Long Sear drags at S.A. cock? Adjust bottom hand Hammer Jammed, won't cock Rebound loose on pin? Check/replace reb. pivot pin Hammer Jammed, won't cock Bolt doesn't return? Adjust rebound/bolt tang

Hammer Jammed Skirt catches safety? Clearance skirt/safety Hammer Catches upper safety Low safety clearance? Replace rebound


WHERE WHAT IS IT? CHECK FOR: REMARK: Hammer Misses upper safety Wrong hammer/safety? Install correct parts Hammer Hits frame Prevents SA overhaul? Clearance frame Hammer Drags Frame high spots? Deburr/level high spots Hammer Drags Skirt uneven? Polish and level skirt Hammer Drags Too wide? Polish sides Hammer Strut sticks Oil stuck? Solvent clean Hammer Strut sticks Pin overstaked? Refit/replace hammer

Hammer D.A. rough Strut tip rough/square? Point and polish strut tip Hammer D.A. drags Sear extension rough? Polish top of sear extension Hammer Early D.A. drop Strut let out short? Correct strut let out Hammer DA strut hits sear Let out too far? Replace strut Hammer Strut won't return Let out O.K? Check rebound hammer seat Hammer D/E firing pin drags Pin tip bent? Straighten or replace pin Hammer Primer strikes high D/E firing pin high? Clearance bottom back of pin Hammer Primer strikes low D/E firing pin low? Clearance top back of pin

Hammer Misfires Pin protrusion short? Replace firing pin Hammer Misfires Pin protrusion O.K? Check for bent firing pin Hammer Misfires Pin protrusion O.K? Check/adjust weak mainspring Hammer Misfires Headspace open? Check/adjust headspace Hammer Primers ruptured Pin protrusion long? Adjust/replace firing pin Hammer Pushes off Cocking notch altered? Replace hammer Hammer Pushes off Cocking notch damage? Replace hammer Hammer Pushes off Mis-cut sear? Adjust sear/replace trigger

Hammer Stirrup pin catches Stirrup pin loose? Replace/stake pin Hammer Strut pin drags frame Strut pin loose? Replace/stake pin Hammer Won't rebound Hammer heel altered? Replace hammer assembly Hammer Won't rebound Hammer heel O.K? Replace rebound I firing pin Misfires Firing pin broken? Replace firing pin I firing pin Erratic Wrong pin installed? Replace firing pin I firing pin Misfires, erratic Wrong spring installed? Replace spring I firing pin Punctures primers Wrong pin installed? Replace firing pin I firing pin Punctures primers Protrusion long? Dress/replace firing pin Rebound lev. Binds Pivot pin loose? Replace pivot pin Rebound lev. Binds Pivot pin part way out? Replace with longer pin Rebound lev. Won't pick up bolt Cam too high? Adjust rebound lower Rebound lev. Won't pick up bolt Burrs on bolt tang? Carefully remove burrs Rebound lev. Won't pick up bolt Front triangle rough? Polish triangle Rebound lev. Won't pick up bolt Front triangle thick? Reduce slightly and polish Rebound lev. Won't pick up bolt Bolt tang mis-adjusted? Adjust bolt tang

Rebound lev. No instant pick up Cam too low? Adjust rebound higher Rebound lev. No instant pick up Bolt tang mis-bent? Adjust bolt tang Rebound lev. No instant pick up Bolt tang altered? Replace bolt Rebound lev. Bolt won't drop Front of cam long? Adjust cam Rebound lev. Bolt won't drop Front of E/I cam sharp? Slightly round corner Rebound lev. E/I bolt drags Hard over cam? Clearance front of cam Rebound lev. D bolt drags Hard over cam? Change front cam angle Rebound lev. Bolt slips off Bolt tang mis-bent? Adjust bolt tang

Rebound lev. Bolt drops off Front of cam not 90* ? Replace rebound lever Rebound lev. Bolt drops off Front triangle over cut? Replace rebound lever Rebound lev. Bolt drops off Front of cam short? Replace rebound lever Mainspring Drags top of rebound Bottom end sharp? Radius bottom mainspring corner

Mainspring Stirrup saddle drags Saddle corners wide? Dress to clear frame/sideplate Mainspring Too strong Over tensioned? Adjust recurve Mainspring Weak Spring bend O.K? Re-bend/re-tension spring Mainspring Weak Won't re-tension? Replace spring Mainspring Knee Cracked, checked? Replace mainspring Mainspring Altered Ground, thin? Replace mainspring Mainspring Over-bent Too much recurve? Replace mainspring Bolt Spring Limits bolt travel Too long? Adjust spring Bolt Spring Soft, weak Wrong spring, short? Replace bolt spring


WHERE WHAT IS IT? CHECK FOR: REMARK: Crane Stem loose Frame O.K? Replace crane Crane Stem loose Crane O.K? Replace frame Crane Stem binds Dirt/oil stuck? Clean stem and frame tunnel Crane Stem binds Burrs, machine ridges? Dress stem/tunnel I.D. Crane Early stem endplay Detent loose? Replace/refit detent Crane Early stem endplay Detent O.K? Peen or install bearing washer Crane Late detent stiff Spring too long? Check/shorten spring

Crane Hard closing Bent or sprung? Thimble gauge check Crane Hard closing Fails gauge test? Align crane Crane D arm/stem loose Pin missing? Replace pin or crane Crane D arm/stem loose Pin in place? Replace crane Crane Bushing won't start Crane threads damaged? Re-tap if possible Crane Threads damaged Won't re-tap? Replace crane Frame Pins worn Trigger/hammer loose? Replace frame pin Frame Pin loose in frame New pin loose also? Factory oversize S.K. pin Frame Recoil plate loose New plate fit tight? Install new recoil plate Frame Recoil plate loose Is new plate loose? Factory oversize S.K. plate Frame Recoil plate loose New plate is loose? Factory crimp recoil plate Frame Ignition erratic D/E pin port oversize? Replace recoil plate

Frame Ignition erratic I pin port altered? Replace frame Frame Barrel loose Shoulder/threads O.K? Re-qualify barrel Frame Barrel loose Barrel thread problem? Replace barrel Frame Barrel loose Frame threads O.K? Replace barrel Frame Barrel loose Frame thds. damaged? Replace frame Frame Threads tight Is screw correct? Clean/chase threads Frame Finish worn Otherwise O.K? Polish/re-blue Frame Rust (light) Interior O.K? Polish/re-blue

Frame Rusty (outside) More than light pitting? Replace frame Frame Tweaked, twisted Cylinder misaligned? Replace frame Frame Cracked No further check. Replace frame Frame Altered No further checks. Replace frame Frame Stocks loose Grip pin missing? Replace pin Sideplate Slight tweak Frame O.K? Flatten/straighten sideplate Sideplate Tweaked, bent Frame O.K? Factory replace plate Sideplate Resistant fit Edge nicks? Dress edges Sideplate Hand drags Hand slot burrs? Dress slot, edges Sideplate Drags hammer High spots, raised nos.? Level and dress inside surface Rear Sight Blade damage Leaf body O.K? Replace blade screw Rear Sight Won't elevate Elev. screw problem? Replace screw Rear Sight Won't lower Elev. screw stripped? Replace screw Rear Sight Won't lower Frame thds. damaged? Re-tap/inst. oversize screw Rear Sight Crooked Leaf body problem? Replace sight assembly Rear Sight No windage adj. Screw stripped? Re-tap or replace sight leaf

The following checks are based on machine rest test firing to rule out hand held and misc. factors:

The Revolver Inaccurate Erratic ignition? Check open headspace The Revolver Inaccurate Headspace O.K? Check mainspring tension The Revolver Inaccurate Mainspring O.K? Check firing pin protrusion The Revolver Inaccurate Protrusion O.K? Check for bent firing pin The Revolver Inaccurate Ammo problem? Replace ammo The Revolver Inaccurate Ammo problem? Inspect reloads

The Revolver Inaccurate Ammo problem? Review reloading procedure The Revolver Inaccurate Ammunition O.K? Inspect sights The Revolver Inaccurate Sight on angle? Straighten/replace sight The Revolver Inaccurate Shoots low? Adjust high front sight The Revolver Inaccurate Shoots high? Replace/stretch low front sight The Revolver Inaccurate Sights O.K? Check forcing cone The Revolver Inaccurate Forcing cone O.K? Slug barrel diameter The Revolver Inaccurate Barrel dia. test O.K? Plug gauge test alignment


WHERE WHAT IS IT? CHECK FOR: REMARK: The Revolver Inaccurate Alignment O.K? Carbon ring in chamber leads? The Revolver Misfires Firing pin short? Replace firing pin The Revolver Misfires D/E firing pin bent? Straighten/replace firing pin The Revolver Misfires Hammer falls early? Adjust D.A. strut let out The Revolver Misfires Hammer falls early? Replace short D.A. strut The Revolver Misfires Bolt index late? Adjust bolt timing The Revolver Misfires Reb. drags hammer? Adjust rebound

The Revolver Misfires Reb. stops hammer? Adjust rebound The Revolver Misfires Mainspring weak? Adjust/replace mainspring The Revolver Shaves lead Barrel/cyl. misaligned? Align crane The Revolver Shaves lead Barrel/cyl. misaligned? Replace worn bolt

The Revolver Shaves lead Bolt head O.K? Replace worn cylinder The Revolver Shaves lead Undersize forcing cone? Recut cone The Revolver Shaves lead Excess barrel gap? Correct endplay The Revolver Shaves lead Excess barrel gap? Re-qualify barrel The Revolver Shaves lead Fires out of time? Refit hand/bolt/strut The Revolver Spits lead, etc. Damaged forcing cone? Replace barrel Bullets Keyhole Oversize forcing cone? Requal. barrel/recut cone Bullets Keyhole Muzzle crown problem? Recut crown Bullets Keyhole Over diameter bore? Replace barrel Bullets Keyhole Fires out of time? Refit hand/bolt/strut Bullets Keyhole (2"bbl.) Incorrect bullet style? Check different bullet Bullets Keyhole (2"bbl.) Bullets O.K? Try lower velocity

Action Lubrication Data:

Factory specified lubricant- Chemlube 303 by Ultrachem, Inc.

Factory specifications require action lubrication at the following points:

1. Hand and rebound contact points

2. Hammer/hammer pin

3. Trigger/trigger pin

4. Frame safety slots and recesses

5. Sear and top/bottom sear extension surfaces 6. Rebound cam and bolt actuator tip

7. Hand surfaces and frame post

8. Frame/rebound pivot pin

9. Hammer heel/rebound hammer seat

10. Trigger/hammer bearing surfaces

SECTION

II

The Colt DA Revolvers, Section II 139

Section II

Editors Note:

Jerry Kuhnhausen has written several individual shop manuals on Colt's double action revolvers. These

books include most model variations from 1903 to date. This manual (Volume I) combines his revolver

smithing data on Colt D, E and I frame double action revolvers.

The first section covers detailed inspection, parts checks, refitting, and basic repair. The Troubleshooting

Guide, included at the end of the first section, is retained from the original D, E, and I model shop manuals. It is an easy reference, regardless of ability level.

In editing this second section, we have taken an assortment of specific revolver smithing jobs from the

author's D, E, and I frame manuals. We have included the majority of the most frequently asked for shop

gunsmithing work, and have given extra details on some of the more everyday bench work. In this section

there are also examples of some of the most complex jobs revolversmiths are asked for. As in Section I,

basic tools and shop tools needed are shown with the work being done.

The work shown in this manual follows current factory service procedures except where special "factory

only" type tooling and fixtures are used. In these cases, due to field non-availability of such tooling,

parallel procedures adapted for easy use by field armourers and revolversmiths are suggested.

With Sections I and II of The Colt Double Action Revolver- A Shop Manual. Volume I, you have at hand

more detailed information about the workings of Colt D, E, and I frame double action revolvers than has

ever before been published in any single book.


Figure 179- Shows a sight ramp slot typical of Python and 6"

Diamondback models. The higher Patridge sight [.190" above

the ramp], at right, is used with the Elliason rear sight. The

#51345 replacement sight pin, illust. at top, is used in both

Python and 6" Diamondback models. The older Officer's

Model Match uses #50060 pins.

Figure 180- Shows Python front sight blades, at top, identified

by their double mounting pin holes. The 2 1/2" Python uses a

1/10" front sight blade, while all others use the standard 1/8"

blade. The 6" Diamondback front blades [also 1/8"], below, are

identical except for their single pin hole. All std. blades are

.160" high.

About Front Sight Blades-

Front sight blades used with Colt

Accro and Elliason adjustable rear

sights are easily identified by eye. The

taller, .190" Patridge front blade is

used only with the Elliason rear sight. In Colt revolvers, this combination is

used only with the Python model.

Python front blades have two retaining

pin holes. The 2·5" Python's extra

short sight radius requires a narrow

1/10" front sight blade for a correct

sight picture. All other barrel lengths

use the standard 1/8" blade.

The 6" Diamondback front sight

blade is actually a standard 1/8" Python blade, but with only one pin

hole.

The Officer's Model Match and earlier

target versions use special front blades

designed only for those models.

Sight Blade Part Numbers

Diamond/6" #56624

Python/2·5" #53647

Python/2·5" #53647N

Python/3-8" #51868 Python/Red #55405B

Patridge #53960B

O.M. Match/38 #51362

O.M. Match/22 #51364

Check Sight Blade Fit

If front blade has sideplay:

1. Replace the blade.

2. If still loose, squeeze sight ramp, [with blade, no pins] between

bronze vice jaws.

If sight pins are loose:

1. Replace sight pins.

2. Or make an oversize pin. Dimple

the pin full length.

3. Use a punch slightly smaller than

pin diameter when removing sight

pins. 4. When installing sight pins, use a

1/8" diameter punch to prevent

slip-off damage.


Colt Accro Adjustable Sights

The late Colt Accro sight uses a

slightly taller Micro- type rear blade.

Windage clicks are also machined into

the face of the adjusting screw. But,

Micro similarity ends there. The leaf body of the Accro sight was designed

to provide more than enough

elevation. This makes it possible for

the sight to be used throughout the

Colt line without the need to change

standard front or rear blades. See

figures 183 through 186 for

disassembly and assembly.

Accro Sight Assy. Numbers-

Standard #51693

White Line #54402B

Early Colt Accro Sights-

This discontinued sight is similar to

the late style Accro. See figs. 181 and

182. Three parts for this sight are still

listed: the #51193 windage spring, the

#51194 elevation spring, and #51195

detent ball. For other early Accro

parts, contact suppliers of discontinued parts such as GPC, West

Hurley, N.Y.

About Colt Elliason Sights-

The large back of the Colt Elliason

match sight is the adjustable rear

blade. With this sight design, the

windage screw threads directly into

the sight blade. The screw is then held

captive in the leaf body by the staked windage screw nut on the left side. If

windage adjustment is oil stuck, the

windage screw can be freed by

soaking the sight in penetrant, or in

acetone. Only two parts are factory

listed for this sight: the #53739

elevation screw, and #51194 elevation

spring. Assembly number is #94093.

Figure 181- Shows an exploded view of Colt's standard Accro

adjustable rear sight, used on Python, Diamondback, J, V, AA

and Ace .22 models. Turning the windage screw clockwise

moves the sight to the left. Turning elevation screw clockwise

lowers the sight. Bullet point of impact is moved in the same direction.

Figure 182- Shows an exploded view of the early style Colt

Accro adjustable rear sight, used on O.M. Match and early I

frame models. Early Accro sights are identified by their

rounded front leaf shape. This sight used a #51191 elevation

screw, #51195 detent ball, #51192 windage screw, and #51189

blade.


Figure 183- Shows a Colt Accro sight blade being removed

after the windage screw has been taken out. The easiest way to

remove most Accro sight blades is to first pull the blade back

against the spring with a thumbnail. Then, slip a 3/64" punch

underneath to further compress the spring- and rock the blade

up and out.

Figure 184- Shows a white outline Accro sight blade and

windage spring, above. The rounded bottom left point of the

blade picks up the spring. The blade is being installed in the

leaf, below. The sharp right point faces the windage screw. The

blade is pushed in to compress the spring, and then down into

the leaf slot.

Remove Accro Sight Blade

Well machined Accro sight leaf bodies

plus the stronger windage springs

used, make Accro blade adjustment

more consistent than many others of

similar type. But, sometimes, this can make the rear sight blade a little

difficult to remove. See figure 183.

To remove the sight blade:

1. Unthread and remove the windage

screw.

2. Draw the sight blade to the left,

and hold it hard against the

windage spring.

3. Then, rock the sight blade up and out of the leaf body. Be prepared

to catch the spring and blade if

necessary.

4. If the blade will not lift and clear

the leaf body, insert a 3/64" punch

under the leaf, compress the

spring, and tip the blade up and

out of the slot in the leaf body.

Install Accro Sight Blade

1. Clean and de-grease the sight leaf slot.

2. Check the windage spring against

a new replacement. If the spring

is weak, it may not hold a positive

blade position. When short or

weak, the spring must be

replaced.

3. Check windage adjustment screw.

To hold detent, slots at the end of

the screw must be sharp. If slots

are blurred or questionable, replace the windage screw.

4. Install the windage spring.

5. Insert the rounded bottom point of

the sight blade and engage the

windage spring. Compress the

spring and snap the sight blade

down into place. See figure 184.

6. Install windage screw.


Remove Accro Rear Sight Elevation

Screw

Thread damage is the usual reason

elevation screws are replaced.

However, if the sight is hit when

elevated, the bottom of the pin slot skirt can break off where it meets the

elevation pin.

Remove the elevation screw as

follows:

1. Push out the elevation pin with a

1/16" punch.

2. Hold the sight assembly over a

small parts box.

3. Place thumb over the top of the screw and slowly push it out from

the back. Do not lose spring and

detent balls. See figure 185.

Install Accro Elevation Screw

1. Remove dried oil and dirt from the

leaf detent recess.

2. Check detent spring tension.

Replace if weak.

3. Coat the detent spring with

assembly grease and install in the elevation screw.

4. Place leaf upside down on the

bench; preposition the elevation pin

and screw.

5. Grease tip of 1/16" punch and pick

up one ball.

6. Insert the ball at one end of the

detent spring and start the screw into

the hex recess.

7. With the 1st ball in place, tip the

elevation screw just enough to take the 2nd ball.

8. Depress the second ball, push in the

elevation screw until it lines up with

the pin. Then push in the elevation

pin. See figure 186.

Install Sight In Frame

Pre-install elevation springs with

assembly grease. Then, pin the sight

leaf body in the frame. Hold the leaf down while threading the elevation

screw into the frame.

Figure 185- Shows removal of an Accro rear sight elevation

screw pin. This pin retains the elevation screw, detent spring,

and two detent balls in the leaf body. Take extra care to prevent

loss of detent parts as the elevation screw is removed from the

leaf. I suggest removing the assembly over a parts box.

Figure 186- Shows installing an Accro rear sight elevation

screw and detent assembly in an upside down sight leaf body.

During handling, mechanical assembly grease helps hold detent

spring and balls in place. For easy assembly, line up the detent

spring and balls across the hex corners of the elevation screw

recess.


Colt Improved Sights

As you look over your revolver to sight it the front sight should just fill the rear notch, the top of the front

sight should be even with the top of the bar of the rear sight with an even distribution of light on each side and both sights in line with the spot on the target just below the point you wish to hit. Colt revolvers are

sighted at 15 yards to place the shots 3/4 inch above the point of aim. At 10 to 12 feet hold ON the object

you want to hit. There is a false belief that the shooter must guess how much to allow for

the flip of his pistol. It is true there is a recoil, but the shooter doesn't have to do any

guessing. When Colt arms are tested the sights are adjusted and allowance is made for the

upward flip due to the recoil. If the Arm is properly grasped and the sighting is correct the

shot will be accurately placed.

The standard front sights furnished with Colt Revolvers and Automatic Pistols designed for

regular Police, Military, home and other protective service as well as for the hunter, tourist

and general outdoor use are of the "fixed" variety, that is, they are not adjustable. The front sight is so constructed that the Arm may be easily drawn from the pocket or holster. It is

strong and carefully made, firmly welded into a slot cut in the front of the barrel, or slide,

and tapered at the top to a width that has proven best for all around shooting.

Rear sights in Colt Revolvers are formed by a groove along the top of the frame cut to proper width to

correctly catch the front sight. Rear sights of all Colt Automatic Pistols are movable except the Cal. .25

Pocket Model which is machined as an integral part of the slide. The "Woodsman" model, .22 calibre rear

sight is adjustable for windage.

The standard sight equipment of Colt Target Arms — New Service Target, Officer's Model Target and

Police Positive Tar- get Revolvers, "Camp Perry" Model Cal. .22 single shot Target Pistol and "Woodsman" Model .22 calibre

Automatic Pistol is the square or "Patridge" front and square cut

rear as shown in the accompanying illustration. Regulation Bead

sights will be supplied on any of these models when so specified,

at no extra cost. Ivory Bead or Gold Bead front sights may be had

at a nominal additional cost. Unless otherwise specified, the

square or "Patridge" sights will be fitted to all Target Arms

ordered.

Figure L- Early Colt data discusses sight geometry. Later adjustable Accro and Elliason rear sights

provide even more flexibility. -Courtesy Colt Firearms


Figure 187- Shows a Millett Series 100 Adjustable Rear Sight with white outlined blade, installed on a

Colt Diamondback. With 6" barrels, Series 100 sight adjustment is 5/16" per click at 50 yards, and 5/8"

per click at 100 yards. This sight can be used on all Python and Diamondback models and with either

original factory front sight blades or with Millett's 1/8" white or orange bar front ramp sights. Standard

rear blade height is .312", with .360" and .410" rear blades also available. Exploded parts illustration-

courtesy Millett Sights


Figure 188- Shows removing a frame pin with an arbour press.

The press ram has been drilled to receive the shank of the

frame pin chuck. The correct diameter pin removal insert is

installed in the chuck. The inserts are hollow ground to prevent

slip-off, and slightly under pin diameter to prevent frame pin hole damage.

Figure 189- Shows a new replacement hammer pin being

pressed in with a bench arbour press. The hammer pin holder,

shown below, fits into the press ram and holds the hammer pin

at 90 degrees to the frame. To prevent frame and pin hole

damage, the frame is held across the press bed on an

aluminium levelling block.

Replace Trigger or Hammer Frame

Pins

If there is any doubt about the cause of

a loose trigger or hammer, always

check the questionable trigger and/or

hammer pin hole against a new replacement frame pin before pressing

the existing pin out of the frame.

When looseness follows the pin, or

when pins are visibly worn, rusty, or

undersized, they must be replaced.

Remove Frame Pin

1. Install the correct pin removal

insert in the frame pin chuck. See

figure 188. 2. Place frame on aluminium

levelling plate, and position on

arbour press bed.

3. Press out frame pin.

4. If pin is resistant, support frame

wall with a brass or aluminium

reinforcing block.

5. Always use the frame support

block when pressing pins out of

alloy frames.

Install Frame Pin

1. Install the frame pin chuck in the

arbour press ram.

2. Then, install the correct frame pin

in the chuck.

3. Position the frame on an

aluminium levelling plate. See

figure 189.

4. Coat frame pin hole and pin with

antiseize compound.

5. Align the frame, start the pin, and press into place.

About Loose Frame Pins

When frame pin holes are loose,

confirm by pressing in a new

replacement pin. If pin shank fit is still

loose, ship the frame directly to

factory service for installation of an

oversize, or SK, trigger or hammer

pin. In this way, the correct frame pin centres will be preserved.


Frame Work-

Re-facing the Ratchet Seat

Due to the cost involved, and because

cylinder endplay is increased with the

removal of surface material, the ratchet seat is re-faced, in the field,

only as a part of ratchet or

cylinder/ratchet replacement and

barrel work. See figures 190 & 191.

Also, see barrel- cylinder replacement

sections and barrel set-back work.

With steel frames [only] the following

judgement factors apply in ratchet re-

facing:

1. Can the seat surface be cleaned at .003", or less?

2. Cost of parts, materials, and etc.-

plus cost of labour.

3. Is the revolver worth it? Warning:

Do not attempt seat refacing in

alloy frames- the risk of frame

damage during barrel removal is

too great.

More About Ratchet Peening

While it's true that very lightly peened steel frame ratchet seats may clean up

at less than .003", keep in mind that

when ratchet peening is found, other

frame damage is usually present that

would, in itself, reject the frame.

Ratchet peening can range from light,

sometimes shiny, seat marking- all the

way to indented, bent, and cracked

frames. Severity of the problem

depends mostly on degree of misuse, whether the frame is steel or alloy, and

the size of the frame.

Ratchet peening very quickly work

hardens aluminium alloy frames,

causing brittleness and increasing the

potential for cracks, [if peening hasn't

already cracked the frame].

Figure 190- Shows an I frame with a slightly rough ratchet

seat. Seats can be re-faced [with ratchet, cylinder/ratchet

replacement work only] providing that the surface will clean at

.002 - .003" below original factory seat depth. Don't re-face

seats in ratchet-peened frames, or in alloy frames. Indicate surface, before cutting.

Figure 191- Shows a facing cutter and frame set up for spot-

facing and cleaning the ratchet seat surface. The cutter isn't

piloted so the frame can be fed to the cutter. Since cylinder

endplay is increased by this work, it is done only as a part of

cylinder/ratchet assembly replacement. Barrels are removed for

this step.


Figure 191A- Shows an E frame recoil plate being pressed out

on an arbour press. A relieved aluminium block aligns and

holds the frame and recoil plate at 90 degrees to the contoured

punch insert installed in the press chuck. Replacement recoil

plates are then pressed into the frame. The recoil plate is then

re-crimped.

Figure 191B- Illustration shows an E frame after recoil plate

replacement and re-crimping. The cross hatched area, see

arrow above, must be stoned to remove flaring and/or burrs.

The recoil plate must be level with the frame. High spots can

make the action feel rough, interfere with rotation, and close

headspace.

Frame Work, Cont.-

Replace Recoil Plate

D and E model recoil plates that have

been altered, or that have firing pin

ports enlarged from misalignment of the firing pin, must be replaced.

Enlarged firing pin ports can allow

primer cup material to backflow into

the port. This can make actions seem

rough, or, in extreme cases, jam

cylinder rotation. This effect is made

worse when the recoil plate is also

flared or "puckered" at the pin port.

Although pin port enlargement is

usually found only in centerfire recoil plates, it is sometimes found in

rimfires. Plates in this condition must

be replaced.

After replacement, a recoil plate that is

not at the same level as the surface of

the frame will affect headspace. If the

plate is too high, it must be dressed to

agree with frame level. See figures

191A and 191B.

Model/Cal. Part number D/.22 #56137

D/.38 #56523

E/.22 #50477

E/.38 #50445

About Loose Recoil Plates-

If the replacement recoil plate seems

loose before crimping, recheck parts

stock for another plate that may be

.001" or larger in diameter. If the larger diameter plate is also loose,

check with factory parts for

availability of an "SK", or oversized

plate.

Bent Firing Pins

Be sure that frozen, or bent, firing pins

are corrected after plate replacement.


Figure 192- Shows the older field service crane aligning system, developed for early style, screw-on

ratchet type cylinders. The direction the crane had been sprung was determined by closing the cylinder

and then pushing it either right, left, up, or down, until the latch pin dropped into place. Then, the cylinder

was impacted in the same direction with a plastic or rawhide mallet [see above] until the latch pin entered

the ratchet recess. This method is still workable, but only to the extent that the cylinder, ejector star, and

latch pin recess are on exact crane centreline. If the ejector star, guide pins, or ratchet do not agree, or are

off centre, for any reason, the crane can't be correctly aligned the old way. Instead, I suggest using the current factory thimble gauge method with both early and late style revolvers. Results are 100% positive.

Ejector/ratchet problems are easily identified. See figures 193 through 196.


Figure 193- Shows the crane open with thimble gauge still

installed after first alignment check. In this case, the crane

barrel must be moved in the direction shown by the arrow,

above. This is done by tapping or striking the crane, where

shown, with a plastic mallet or round lead bar. Check crane alignment between adjusting taps.

Figure 194- Shows the tap, or strike direction needed to move

the crane barrel as shown in the inset, above. Movement in this

direction requires an impact where indicated on the crane

barrel. In this step, alignment is best controlled with the frame

placed on its side on a wooden bench block. Strike lightly,

recheck alignment.

Align or Straighten Crane

When sprung, Colt revolver cranes

usually require only slight corrective

alignment. A few cranes, and

especially those in revolvers that have

been dropped or abused, may be extremely bent to the left or right. But,

the majority are easily realigned as

shown in figures 193 through 196.

Unless beyond repair, it is possible to

straighten even a crane that has been

bent hard to one side by first clamping

the closed crane and frame between

brass vice jaws, and then realigning

the crane barrel while in that position.

There are four basic crane aligning

steps. The correct combination of these steps will move the crane in any

required direction. Make adjustments

carefully to prevent over-bending. The

following rules apply:

1. Always keep the thimble gauge

on the crane barrel while tapping

or striking the crane. Tap the

body of the gauge, not the crane

barrel.

2. Prevent over-alignment by re-

checking thimble gauge position after each impact.

3. Keep the aligning wedge smooth

by filing or sanding the surface as

needed. Before using wood

wedges, I suggest rubbing the

surface on a paraffin block to

keep it smooth and non-resistant.

4. Don't tap or strike the wedge or

thimble gauge if the gauge tip is

still inside the latch pin tunnel.

The alignment wedge shown in figures

195 and 196 is easily made from a

piece of 1 1/8" x 5" hardwood.


Crane Alignment Steps

1. When doing the yoke open,

downward strike, step shown in

figure 193, place the butt of the

revolver on the bench while

holding the barrel firmly. Then strike the body of the thimble

gauge with a plastic hammer or

lead bar, at the location shown.

2. When moving the yoke barrel by

striking it while inside the frame,

tap the body of the thimble gauge

with the end of a wooden hammer

handle or lead bar, where shown

in figure 194. This step is made

much easier by placing the frame

on a wooden bench block before crane adjustment.

3. The aligning wedge is used for up

and down crane barrel

adjustments. Remove thimble

gauge when making wedge

adjustments, and then reinstall it

to recheck crane alignment. Place

the wedge at the end of the crane

barrel and against the inside back

of the frame, as shown in figures

195 and 196. Tap the wedge

gently; the ramp shape generates a lot of leverage. When hit too

hard, the wedge will move the

crane more than the estimated

amount.

4. Carefully adjust, or repeat

adjustment, in any of the four

steps until you have perfect crane

alignment.

5. When crane barrel alignment is

correct, the tip of the thimble

gauge easily enters the latch pin tunnel on exact centre just as the

crane closes. The gauge will slip

in smoothly, without having to

apply pressure on the crane arm

or crane barrel.

Figure 195- Shows an aligning wedge being used to lift the

crane barrel up, after gauge checking the crane. See inset

above. Installing the wedge on the left side of the frame secures

the crane arm while the crane barrel is being moved upward.

Cranes may need adjustment, or a final re-adjustment, in a second direction.

Figure 196- Shows the aligning wedge being used again to

move a crane barrel downward. See inset, above. When a crane

has been aligned correctly, the tip of the thimble gauge will

easily enter the latch pin tunnel on exact centre, just as the

crane closes, and without the need to exert pressure on the

crane arm or crane barrel.


Figure 197- Shows an E/I cylinder bolt that is worn out at the actuator tip, although it may not seem so at

first glance. A "guesser" attempted to refit this bolt. By now, it has everything imaginable wrong with it.

See list, below.

1. Bolt head width- was polished too thin for correct cylinder bolt slot fit- and is also loose in the frame window. When the bolt head is thin, either from wear or mis-fitting, it should be replaced, for that

reason alone.

2. Bolt head width- was further narrowed by re-polishing the left side of an already too thin bolt head.

3. Bolt head width- was reduced even more by over-polishing the frame side (back) of the cylinder bolt

body.

4. Bolt stop shoulder- was over-filed; this, in turn, raised the head and lowered the bolt actuator tip too

much. By itself, this is a cause for bolt replacement.

5. Bolt head contour- is wrong and no longer matches the cylinder's bolt slot leads. Elevating the bolt

head too much shifts head contour somewhat off centre.

6. Bolt head height- was readjusted, and is now too low for correct cylinder slot engagement. Also, the

head still has the above off-centre contour.

7. Bolt tang- was over-bent, re-bent, and hardened- by itself a reason for replacement. This was probably an attempt to solve a worn actuator tip problem.

8. Bolt actuator tip- was shortened, probably in an attempt to re-square a worn- round actuator tip. Keep

in mind that the main cause for bolt replacement is wear rounding at the rear corner. Altering or

modifying the tip never works.

9. Bolt actuator tip- the side was altered, probably in an attempt to solve a "no return" problem.

Any alteration of the bolt actuator tip, aside from burr removal and slight, careful bending to improve bolt

drop timing and return, will destroy the bolt tip. When such bolts are found, replace them. Don't try to

repair misfit bolts with further modification.

Before replacing a rebound lever, always check to see if the rear corner of the bolt actuator tip is excessively worn (heavily rounded off). Since a worn bolt will have to be replaced, anyway, it's a better,

faster, and, by far more economical practice to replace the bolt first, and then fit the rebound only once.


Replace Cylinder Bolt

Normally, cylinder bolts wear at the

right side of the head, at the top riding

point, and at the actuator tip. In many

cases, a worn original bolt can be

elevated and refit if refitting is correctly done. But when the bolt is

loose in the cylinder from wear, or has

been misfit too narrow, the bolt must

be replaced. Fit new bolts as follows:

1. Always check new bolt heads

against cylinder slots.

2. Lightly polish left and right sides

with #400 sand cloth. But, do not

undersize.

3. Dress left side if bolt head drags in frame window.

4. Check bolt pivot screw tension.

Without the spring, bolt must

lightly drag frame with pivot

screw fully seated.

5. Check and adjust final bolt head

height, contour, and riding point.

See figure 199, & bolt fitting,

Section I.

6. With earlier D frames, check the

stepped bolt stop in the frame. If

the step is intact, an early style bolt may be installed. Otherwise,

level the step and install a late

non-stepped D bolt. See stop

cross-section in fig. 199.

7. Install bolt and spring. Seat pivot

screw, then check position of bolt

actuator tip vs. rebound cam.

Rebound adjustment is almost

always necessary and must be

done before adjusting bolt timing.

See rebound fitting sections. 8. If bolt drops early with correct

rebound, bend bolt actuator tip

toward rebound.

9. If bolt drops late, bend tip back

slightly or check bypass bevel at

front of rebound. See bolt timing

data, Sect. I.

Figure 198- Shows Colt E/I and D replacement bolts. These

well made parts are sized at full pre-fit dimension, or a tad

oversize if compared to most already fit parts. This sizing helps

compensate for frame and bolt slot wear, and can sometimes

help a low rebound. Bolt tangs must be adjusted for correct bolt

timing.

Figure 199- Shows checking bolt engagement in an I frame, at left. E/I bolts should enter cyl. slots 1/32", or approx. .033" on

the high side, and a min. of .005" on the low side. Actual bolt

engagement is checked with feeler gauge strips at the bolt stop

or with Prussian Blue. Gauge testing is difficult with stepped D

model stops.


Figure 200- Shows I & D replacement triggers. Fitting points

are shown. Critical areas are left at full fitting size. Although it

isn't usual, sears can be a bit long. If not adjusted at fitting, a

long sear will engage at a slightly lower trigger- hammer

position. This can cause sear-hammer drag or "bump" at single

action hammer release.

Figure 201- Shows the safety link pin in an E/I model

replacement trigger. The narrow frame side of the single action

sear is lightly filed, or stoned, for safety lever clearance. To

prevent frame drag, the head of the safety link pin is dressed

until just flush with the safety lever. Warning: do not undersize

the link pin head.

Replace Trigger

D, E and I triggers should be replaced

when the frame pin hole is worn,

loose, or the SA sear has been cut too

short. Triggers that have been altered

by over polishing [are too thin] can move sideways when squeezed, cause

hand problems, and variable sear

releases, as well. Replace these

triggers, also. See figure 200. Fit

replacement triggers as follows:

1. Check trigger/frame pin fit. Ream

trigger pin hole, if tight on pin.

See figure 200.

2. Clearance the frame side of the

S.A. sear and safety link pin head. See fig. 201.

3. Install trigger, safety lever and

safety. Check for link pin drag

and/or upper safety drag inside

the frame recess.

4. If drag is present, lightly stone the

rear edges of the upper safety, but

only until it runs free in frame

recess. Warning: Do not alter the

original thickness of the safety

hammer block.

5. Check trigger width between frame and sideplate.

6. If the trigger fits tight or drags in

the frame, dress the bearing

surface at the left side of the

trigger with #400 sandcloth, until

it runs free.

7. Single action sear fitting and

adjustment is last. See figure 202.

Sear note: Final trigger and hammer

dimensions may vary a bit with each set-up and parts production run. For

this reason, all sears must be carefully

checked. Sear fit must be adjusted to

correct hammer notch engagement and

safe trigger pull.


Figure 202- Shows basic sear fitting angles and sear point correcting angles. Once engaged, the bottom

corner of the single action sear (sear seat) rests on the lower surface of the hammer's single action cocking

notch. Sear seat position is important, since the angle of the sear face from there up, toward either (+) or

(-) determines just how high or low the sear point will be when it contacts the cocking notch engagement

ledge. What this amounts to is that the location of the sear engagement point is important, but the exact

sear angle is not. The bottom corner of the sear is also important and should not be moved (unless the

trigger is long) because sear point engagement starts from there.

With the cocking notch engagement ledge actually over-engaging the sear, the higher the sear point

contacts the ledge, the lower the trigger pressure that is needed to move the sear the remaining distance to

release. And, the lower the position of the sear point, the greater the pressure needed to push back, and

overcome the ledge.

The "Zero Line"- Sear point position, on the line illustrated above, places sear engagement at approx. 1/3

of the way below the cocking notch over-engagement ledge. Typically, trigger pull would be moderate.

The Minus Line- Changing sear angle in this direction (without moving the sear seat) raises the sear

contact point, and reduces single action trigger pull.

The Plus Line- Changing sear angle in this direction lowers the sear contact point, and increases single

action trigger pull.

The C1 Line- Bevelling an E/I sear at this approx. angle, can lower a slightly high engagement point. Very little of the top need be removed.

The C2 Line- Bevelling a D sear at this much flatter angle also lowers the engagement point. Sometimes,

the lightest polishing will do the job.

Fitting sears requires a very light touch. Over-cutting the sear makes trigger replacement necessary.

Never alter the S.A. cocking notch. Best tools for sear work: a good bench light, magnifying glass, hard

white Arkansas stones, and a tool maker's vice or sear fixture. See trigger pull specifications and figure

177.


Figure 203- Shows I and D model replacement hammer

assemblies. Fitting areas are indicated. Before hammer

replacement, check the old hammer for evidence of drag from

possible high spots inside the frame. The old double action

strut should also be checked for unusual let-out; a sign of

possible timing problems.

Figure 204- Shows checking an I replacement hammer in the

frame. Pin fit is checked first. When necessary, the hammer's

frame pin hole is reamed for correct fit. The frame must not

stop the hammer before picking up the SA sear. Also, check for

rebound clearance, and hammer interference at the upper

frame/sideplate joint.

Replace Hammer Assembly

Hammers are replaced when frame pin

holes are worn or oversized, when the

cocking notch has been altered, or the

hammer has been otherwise damaged.

The frame pin hole can be easily checked against a new replacement

pin.

If only the double action strut is worn

or misfit, the hammer assembly need

not be replaced. E/I models use the

#50486 strut and #50454 spring. D

models use #56107 struts and #50400

springs.

New replacement E model hammers and firing pins have been discontinued

by the factory, and are no longer

available. Dealers in used and

discontinued parts are the only

remaining source.

1. Check new hammer fit on

existing frame pin. Ream the

hammer pin hole if pin fit is tight.

2. Pre-polish both sides of hammer

on #400 sandcloth.

3. Install both hammer and sideplate. Check drag.

4. Re-polish and level sides until

drag is gone. Do not undersize

hammer width.

5. Check for correct SA sear pick-up

before the hammer contacts

frame. Adjust frame as needed.

See figure 204.

6. Check for hammer drag at

frame/sideplate joint.

7. Dress frame and sideplate to eliminate hammer drag.

8. Check SA sear engagement, pull,

and push-off.

9. Polish and check DA strut. See

earlier sections on strut let-out

and bolt timing.

10. Check safety clearance. With E &

I model hammers, edge chamfer,

or "under cut" the hammer skirt,

as needed.


Replace Cylinder Hand

Most hands are replaced when they

are short and have been stretched once

before- or because the hand broke

while being stretched. Some are

replaced because they have been altered or damaged by incorrect

fitting. Reverse filing the hand's

tensioning cam is one of the worst

alterations. This rounds off, or angles,

the top of the cam forward and causes

the hand to back up and stick the

rebound. The rebound, in turn, sticks

the trigger.

The only valid hand modification is

stretching and then refitting the top and bottom hands. Beyond this, the

hand must be replaced.

1. Install and hold the hand flat

against side of trigger. Check

hand/frame clearance.

2. Adjust hand to a slight frame

clearance by bending or flattening

the body of the hand as needed.

See fig. 206.

3. Polish the inside [frame side] of

the hand with #400 sandcloth for smooth action.

4. Check hand width against the

frame's hand post. Hand must be

lower than post.

5. If hand is too wide [thick] file the

outside surface, then polish with

#400 sandcloth. Don't undersize

the hand.

6. Install the sideplate, snug the

screws, and check for tip and side

hand drag between the frame and sideplate.

7. If drag or bind is present, adjust

clearance by slight re-bending

and/or dressing the outside of the

hand.

Note: Before further fitting, the hand

must move freely between frame and

sideplate.

Figure 205- Shows new D and E/I replacement hands. Fitting

points are shown in figures 207 and 208. Parts replacement and

production hands are made at full fitting size. Extra height and

overall dimensions provide enough fitting material to allow for

frame and ratchet wear, and for individual frame fitting requirements.

Figure 206- Shows slight hand bend necessary for positive

ratchet function. A new hand may bear too much toward either

the frame or sideplate and need bending or flattening so it

won't dig into the frame or bind on the sideplate. To prevent

sideplate drag, the side of the hand must be slightly lower than

the frame post.


Figure 207- Illustration shows views of a new E/I model replacement hand. Pre-fitting and final fitting areas are detailed, above.

New replacement hands are manufactured extra wide and extra tall. However, finished part sizes can vary

from lot to lot. Generally, as a pre-adjustment step, one to four light file strokes can be taken off the top

hand surface. Previous seating of existing ratchet lug surfaces also affects the amount that can be removed

from the top hand. Caution: Go slowly. Don't overcut the hand.

At rest position, or bottom of travel, the tip of the top hand must be even with the front edge of the

frame's ratchet recess. If let out further, the hand will drag or catch the ratchet as the cylinder is opened

and closed.

The rebound must be adjusted before final fitting and adjustment of the top and bottom hand. Instant

cylinder bolt pick-up must be present for top hand timing, and bolt drop timing must be correct in order to

time the bottom hand. Also see earlier top and bottom hand refitting sections.

Top and bottom E and I hand angles must not be changed from factory original.

When top and bottom hands are being fit to a new, and previously unfit ratchet, the lugs may be

"unequal". Fitting to the wrong lug may lead to overcutting the hand. See page 160 for "unequal" ratchet

fitting procedures.


Figure 208- Illustration shows views of a new D model replacement hand. Pre- fitting and final fitting

areas are detailed, above.

New replacement hands are manufactured extra wide and tall. However, finished part sizes can vary from

lot to lot. Generally, as a pre-adjustment step, two to six light file strokes can be removed from the D

model top hand surface. Use caution. Don't overcut the hand.

At bottom travel position, the forward tip of the top hand must be even with the front edge of the frame's

ratchet recess. When let out further, the hand will drag or catch the ratchet as the cylinder is opened or

closed.

The rebound must be adjusted before beginning final fitting and adjustment of the top hand, since instant

cylinder bolt pick-up must be present to prevent cylinder rotation from jamming the bolt. Bolt drop timing

must be correct in order to adjust the bottom hand. Also see earlier top and bottom hand refitting sections,

and sections on rebound work and bolt timing.

With both D and E/I hands, the top hand angle must not be changed. However, unlike E and I hands, at

let-out and first fitting [only], the engagement angle of the bottom hand surface is changed and adjusted

to agree with the ratchet. Once correctly set, this angle is maintained thereafter.

Although the smaller D model ratchets tend to be more uniform than the larger E/I type, some amount of

ratchet lug inequality can be present. As with E/I models, initial fitting to the wrong lug may lead to overcutting the hand. See the next page for "unequal" ratchet fitting procedures.


Fitting Top and Bottom Hands to New or "Unequal" Ratchet Lugs-

Primarily, the following procedure applies with new ratchets that have not been previously fit, lug

adjusted, and/or lug seated by either the bench or test firing seating methods.

Once the new ratchet has been checked for correct cylinder fit, adjusted to correct shoulder length, de-

burred, and cleaned, (and, with E/I ratchets, 45 degree clearanced for hand bypass) top and bottom hands can be fit.

1. Find the one ratchet lug engagement surface that runs lower (or is thicker) than all the others.

2. Pre-adjust the top hand to fit slightly tight against the lowest ratchet lug. Then, check top hand fit

against all remaining lugs. This pre-fitting step usually makes top hand length fairly close at the other

lugs.

3. Very carefully adjust, or equalize, the above low lug, and recheck top hand function at each lug

position. Dress top hand as needed for smooth cylinder rotation.

4. Then, find the one ratchet lug engagement surface that runs higher (or is thinner) than all other lugs.

5. Pre-adjust the bottom hand to index the cylinder and S.A. cock the action with a slight drag at the

highest lug. After this, check the bottom hand against the remaining lugs. If the remaining lugs are typical, the bottom hand will be slightly long with most.

6. Very carefully adjust and equalize only the necessary lugs. For best long term bottom hand fit (with

lug seating in mind at this point), the bottom hand should bring the cylinder to positive bolt index in

all six chamber positions, with the positive feel of single action sear overhaul, but with a slight

cocking drag just as the hammer toe clears the S.A. sear point.

This sets up the bottom hand and ratchet in a slightly long bottom hand condition, and ready for

hand/ratchet seating by either the bench, or test fire method discussed in Section I. Because the above

method equalizes high and low ratchet lug extremes, it is a time saver. It works very well with all but the

rare irregular or off centre ratchet.

Caution: Before top and bottom hand fitting, all rebound adjustments must be made, and instant bolt pick up must be present. Bolt drop timing must be correct. Normally, a #2 barrette file is used in ratchet lug

adjustment, and very little metal is removed in this work. Use extreme caution. Don't let your file touch

any other surface when filing an individual ratchet lug.


Figure 209- Shows an E type rebound, at top, that was factory fit in 1920. The rebound cam shows a little

wear where the bolt actuator tip bypasses over the front of the cam, but bolt drop timing, having been

correctly set, is still not too early. Just below, three views of very badly misfit I model rebounds are

shown. These rebounds have almost everything wrong with them. If not for the rebound lever, D, E, and I

actions would seem extremely simple. The best way to learn the fine points of rebound cam

troubleshooting and fitting is to closely examine both misfit and correct cams as they operate (or malfunction) with a correctly fit bolt. Use a good magnifying glass. An enlarged view of the cam helps.

Why Rebound Levers are Replaced- see examples, above.

1. The front of the cam has been misfit short- the bolt drops early.

2. The front triangle corner was rounded too high- the bolt slips off.

3. The top of the cam has been filed or stoned lower- this, also, shortens the cam and makes the bolt

drop early.

4. The cam's front triangle corner was moved back by incorrect adjustment-

1. this makes the bolt slip off and drop early.

5. The front corner of the cam and/or front bypass bevel have been angled back from the correct 90 degrees- this makes the bolt fall off the edge of the cam and drop early (or drop, in some cases,

almost instantly).

6. The hammer seat has been overcut- this rebounds the hammer too far forward. The front of the

hammer binds or catches the safety hammer block.

7. The clearance bevel angle is wrong, and/or over cut- this makes an otherwise correctly fit hammer

seat inoperative.

8. End of rebound lever was filed short- this cam is now too low for instant bolt pick-up; if re-bending

can't cure the problem, the lever must be replaced.

9. Front lever was cracked or broken by incorrect bending.

Note 1: Before replacing a rebound, make it a practice to check for a misfit or altered cylinder bolt or bolt

actuator tip. Note 2: Being smaller, the D model rebound cam is even more unforgiving of mis-fitting than the E/I.


Figure 210- Shows E/I replacement rebound fitting steps. The #50462 rebound is listed for the I model,

but is also used by factory service as an E replacement.

1. Polish pivot sides of the rebound lever for free movement inside the frame.

2. Straighten and polish the lever extension to prevent hand or trigger drag.

3. Cut front triangle surface for bolt escape, also polish upper triangle and right side of cam for bolt

return.

4. When needed, lightly break the front bypass corner for bolt drop clearance.

5. If needed, slightly break the front triangle corner for bolt actuator tip return. 6. Polish the front bypass bevel face for smooth bolt bypass.

7. Keep both the front of the cam and the extension lever angles at 90 degrees.

8. Adjust rebound hammer seat to provide .005-.010" hammer/safety clearance.

9. When needed, file 35 to 45 degree clearance bevel to provide rebound- hammer heel clearance and/or

trigger return clearance. File only the minimum amount needed to correct the problem. See figures

212 and 213.

10. Adjust the rebound cam for instant bolt pick up. See figures 214 and 215.

11. When needed, file lever only enough to slightly drop the cam. This is a fine adjustment step, only.

Larger adjustments are done by bending the rebound.

12. Polish edge of extension lever, corner, and sharp edges with #400 sandcloth.

13. Stone or polish bypass bevel (front of cam) to cure a "hard over cam" or slight bolt bypass drag/bind

condition. Don't change the original factory angle. 14. Stone bypass bevel face or slightly round top corner to correct late bolt drop.


Figure 211- Shows D model replacement rebound fitting steps. The #56091 rebound lever is used

throughout the D model line.

1. Polish pivot sides of the rebound lever for free movement inside the frame.

2. Straighten and polish the lever extension to prevent hand or trigger drag. 3. Polish the outside of the rebound lever body to prevent sideplate drag.

4. Cut front triangle surface, as needed, for bolt tip escape and return.

5. Lightly polish the right side of the cam and upper front triangle for smooth bolt return. Warning: use

an extra light touch and keep the top cam square.

6. Keep both the front of the cam and the extension lever angles at 90 degrees.

7. Adjust the hammer seat to provide .005 to .010" hammer/safety clearance.

8. When needed, file a 35 to 45 degree clearance bevel to provide rebound- hammer heel clearance

and/or trigger return clearance. File only the minimum amount needed to correct. See figures 212 and

213.

9. With D cams, don't file or round-off the upper front bypass bevel corner.

10. Adjust the cam for instant bolt pick up. See figures 214 and 215. 11. When needed, file lever just enough to slightly drop the cam. This is a fine adjustment step, only.

Larger adjustments are done by bending the rebound.

12. Polish edge of extension lever, corner, and sharp edges with #400 sandcloth.

13. Change D bypass bevel angle to cure a "hard over cam", or slight bypass drag/bind condition. Don't

change the position of the top front bypass corner.


Figure 212- Illustrates the basic "hammer on lever" rebound

condition. With the hammer "on the lever", and the trigger held

back, the hammer will feel springy, or "hammer bounce"

against the bottom corner of the rebound, if pushed forward.

This prevents full trigger return, and holds trigger/hand

position high.

Figure 213- Shows a sectioned rebound lever and the correct

hammer-rebound [hammer seat] position. A 35 to 45 degree

clearance bevel takes the hammer "off the lever". Then, final

fitting of the hammer seat brings the hammer's safety stop just

to .005-.010" safety clearance position; trigger and hand can

then fully return.

Fitting New Rebound Levers

After deburring/polishing the lever

extension, and pre- fitting the front

triangle, install the rebound with trial

pin, hand, and action parts.

Replacement rebound lever hammer seats and clearance bevels are made

long for fitting, and will ride on the

hammer heel, to some extent. Called

"hammer on the lever", this desirable

beginning condition provides enough

material for proper fitting. From here,

the first step is to fit the rebound's

hammer seat and clearance bevel to

bring the hammer close to the correct

.005-.010" hammer-safety clearance.

See figures 212 and 213.

Caution: File very little surface

material at a time from the hammer

seat and bevel surfaces. When overfit,

the hammer will rebound too far

forward, and drag or catch the safety.

High and Low Rebounds When either

of the following extreme rebound

conditions are found, always adjust

the rebound lever first, to prevent

over-fitting or undersizing the hammer seat.

1. The rebound is too low, and there

is no instant bolt pick up, because

clearance exists between the

rebound cam and the bolt actuator

tip.

2. The rebound lever is too high, and

is not in contact with the hammer

heel. This too long lever, or over

arched rebound must be lowered to fitting range before the hammer

seat can be adjusted. Also see

rebound re-fitting work in Section

I.


Adjust Rebound for Instant Bolt

Pick-Up and Return

After the rebound's hammer seat has

been correctly fit, [which will adjust

out any remaining "hammer on lever"

condition] the rebound will return from firing position smoothly, draw

the hammer back to the correct safety

clearance, and allow full trigger and

hand return. The rebound lever is then

at rest position. If rebound cam

position is correct at this time, the bolt

actuator tip will then return over the

right side of the cam and snap into

position at the top of the cam, ready

for the next cycle. At this point, there

should be zero visible clearance between the top of the cam and the

bottom of the bolt actuator tip. But,

when the cam is low, the clearance

between cam and bolt tip will delay

instant pick-up [the bolt head must

begin downward movement instantly,

when the trigger is moved]. If the cam

is low, the rebound must be carefully

bent, or arched upward until no

clearance remains. See figure 214.

If the cam is even slightly high, the bolt actuator tip will drag, or refuse to

return. In this case, the end of the

extension lever can be filed or stoned

just enough to provide bolt return

clearance. If taken lower, instant pick-

up will be destroyed. When the

rebound is higher than can be adjusted

out with two or three light file strokes,

it should be bent lower. See figure

215. Final bolt drop timing is adjusted

last.

Figure 214- Shows bending, or arching, the rebound lever

higher to adjust rebound cam position. This is done by placing

the rebound lever on a bending fixture [or across steel blocks],

holding it straight, and then tapping with a brass hammer. Bend

rebounds carefully. Use light taps. Install and recheck between

taps.

Figure 215- Shows bending a high rebound lever down. This is

done by holding the rebound lever straight on a steel bench

block and tapping the top of the rebound with a brass hammer. When bending rebounds up or down, always use caution;

rebound levers break easily. Check cam position between each

adjusting tap.


Figure 216- Shows a half-sectioned Python cylinder with excess cylinder/frame endplay. In this example,

the increased endplay was caused by heavy loads which resulted in a stretched frame and seating of the

cylinder collar. Headspace at "A" measures Just at .066" [or half way between the Python maximum of

.070" and minimum of .062"], with the cylinder collar held forward against the frame. Cylinder endplay,

at "B" measures over limit, at .004". With these readings, we can estimate that the cylinder was probably

at near zero endplay and at minimum headspace of .062" when the revolver left the factory.

Why Cylinder Collars Are Stretched-

Subject to the frame and cylinder collar limitations discussed below, stretching and refitting the cylinder collar will:

1. Adjust the cylinder back to the minimum headspace setting.

2. Correct cylinder endplay, in many cases.

3. Or, allow correction for an over-fit [undersized] cylinder collar shoulder.

But, there is a limit to the amount that any collar can be, or should be, stretched. And, stretching the

cylinder collar is not a remedy for all cylinder in-frame problems. Some collars will stretch even less than

the suggested .006-.008" pre- trim limit, before work hardening. Trying to stretch these collars further

will, very likely, damage the collar. In these cases, if frame condition is acceptable, the cylinder assembly

should be replaced. Once headspace and endplay have been corrected by either stretching the collar or replacing and refitting the cylinder, barrel-cylinder gap must then be remedied if excessive. See figures

217 and 218, and barrel work, this section.

Frames that have been stretched and allow cylinder endplay of more than several thousandths may have

other pressure related problems that might suggest frame replacement- or make it necessary. Adjusting

cylinder collars and/or replacing cylinders in excessively stretched frames is not a sound practice.


Stretch Cylinder Collar

Most cylinder collars can be stretched

on a one-time only basis, providing

they are not taken past the suggested

.006-008" max. stretch limit. Beyond

this, risk of thinning the walls, or deforming and damaging the collar, is

too great. Stretching collars a second

time increases the possibility of

damage and is not recommended.

Collars should not be stretched in

cylinders having non-integral, pressed

in, etc., collars.

1. Estimate amount collar length

must be increased to return

cylinder to min. headspace and correct endplay.

2. If length needed is within stretch

limits, secure cylinder and

mandrel in the swaging fixture,

and stretch carefully in steps. See

figure 217.

3. Minimize work hardening by

swaging slowly, and by rotating

the cylinder 180 degrees with

each step. Do not over-stretch the

collar. Warning: Don't use heat on

collar. The cylinder's factory heat treat will be altered.

4. When pre trim length has been

reached, chuck and align the

cylinder in an aluminium

clamping fixture. Trim collar

length to correct min. headspace.

See fig. 218.

Caution: Don't fit cylinder under

min. headspace even if slight

endplay remains.

5. Lightly counterbevel the inside of the newly trimmed collar shoulder

to prevent drag at shoulder and

frame. Note: The cylinder collar

also can be trimmed on a lathe,

but is done faster on a mill, as

shown in figure 218.

Figure 217- Shows a cylinder set up in a collar

swaging/stretching fixture. Once the collar is secured in the

fixture, the jaws are installed and then compressed in a

hydraulic press. After stretching, the cylinder collar will have a

slight swaged down appearance, or reduction in O.D. as shown in the example, above.

Figure 218- Shows the cylinder chucked in an aluminium

clamping fixture. The collar is then milled to length with a

piloted facing cutter. To prevent over-cutting, estimate the

exact collar length needed, then cut only half that amount on

the first pass. Recheck headspace, and final trim the collar to

correct length.


Figure 219- Shows a cylinder/ratchet assembly that was replaced for the four following reasons; any one

of which, by itself, would have been reason enough for replacement: the cylinder collar, at "A", was

altered and cut too short, increasing headspace and endplay beyond maximum limit; on firing, the

cylinder then hit the barrel, marking the cylinder face with circular indentations at "B"; the ratchet lugs, at

"C", have been badly misfit and damaged, and the ratchet shoulder is crooked; also, the guide pin holes in

the ejector star, at "D", were enlarged, allowing excess ratchet sideplay on the cylinder's guide pins.

Why Most Cylinder/Ratchet Assemblies are Replaced-

1. Interior or exterior of the cylinder pitted, excessively worn, or damaged.

2. Bolt slot cuts in the cylinder worn, altered, buffed-out, or damaged. 3. Cylinder collar damaged, or short and beyond stretching.

4. Spline/stem guide inside the cylinder altered or damaged.

5. Ejector star and/or guide pins misfit, altered, or damaged.

6. Ratchet lug, or lugs, misfit, altered, or damaged.

7. Ratchet shoulder misfit, too short, or damaged.

8. Cylinder face/chamber exits rounded, buffed-out, or damaged.

9. Chamber walls, exit throats altered or damaged.

Note: When a frame's ratchet seat has been spot faced to clean up a slightly rough seat, new

cylinder/ratchet assemblies must be installed. After setting headspace, the new ratchet is then fit to correct

cylinder endplay.


About Early D and E Model Replacement Cylinders and Ratchets-

The great number of cylinder variations found in early style, and intermediate, Colt double action

revolvers, could serve to confuse an otherwise extremely simple parts history. This is particularly true

with the small frame models. A brief summary may help.

In 1943, with the press of heavy WW II production, Colt's short cylinder/small frame models, originally made for the older, shorter cartridges such as the .38 S&W, .38 Colt Short, .32 NP, and etc., were

discontinued.

The longer cylinder [and frame] Police Positive Special, Detective Special, and later, similar model

variations, continued in production. In 1947, this long cylinder version was then designated the "D"

frame, and was manufactured continuously at Colt's Hartford plant, until some time in 1984.

Otherwise, with the exception of the late style D model hammer update (and resulting safety change), and

the crane and crane lock update, D model internal parts have remained much the same.

Cylinder/ratchet/rod assemblies were updated in the 1970's to what is now called the "late style".

The earlier small frame cylinders (before the "D" designation) were made in three basic size variations:

1. Short cylinders- made in 1 1/4" length for shorter frame models such as Police Positive and Banker's

Special, chambered for .32 NP, .38 S&W, and other short cartridges.

2. Long cylinders- made in the longer 1 5/8" length for the .38 Spl. Police Positive Special Model, etc.

3. Small diameter cylinders- these were a slightly smaller diameter version of the 1 1/4" cylinder and

were used in the Pocket Positive Model.

Other production and custom cylinder/calibre variations were not uncommon. These include small frame

calibres like the .32 NP chambered in medium frame, E revolvers, and short cylinder calibres chambered

in long cylinder models.

It's likely that medium frame models were given the "E" designation sometime during the Official Police

Model production run. The I model cylinder evolved from the original E cylinder, and runs about .050"

longer in body length. E model cylinders in all calibres, and I model cylinders in .38 Spl. calibre are now

factory discontinued.

As far as cylinder and related replacement parts are concerned, the only cylinder/ratchet replacement

assemblies that are factory available at this time are the late style D model in .22 LR and .38 Spl., and the

late I model in .357. Early style ejector rods and rod heads are still listed.

Parts specialists such as Gun Parts Corp. (formerly Numrich Arms) have purchased most of Colt's new

discontinued factory parts as well as parts stocks from armouries all over the world. Availability can be unpredictable with discontinued and obsolete parts; nonetheless, GPC probably has the largest known

selection of discontinued new, and serviceable used, Colt parts. GPC also manufactures some factory

discontinued replacement items such as E model firing pins and Colt M19l7/New Service bolts, etc.

When ordering non-current cylinders, the above model and cylinder variations must be taken into

consideration. Always specify exact model, calibre, and cylinder type.

When ordering factory discontinued [new] "screw-on" type ratchets, remember that ratchets must be fit

first to the cylinder and then to the frame. When ordering used ratchets, you run the risk that the ratchet

received may be shorter than the one being replaced. For this reason, minimum ratchet height should be

discussed at the time of ordering. Used ratchets will also require fitting. See factory discontinued parts section.


Figure 220- Shows a #53382R I model replacement cylinder

assembly. The #53382R (or N) replaces late type I carbon steel

cylinders. Intermediate I (pre s/n #36190E) #51237R (N)

cylinders are still catalogued, but the #51662 is not. Some early

I frames may require the rod bushing, spring, and crane

bushing kit shown.

Figure 221- Shows an early style crane aligned and chucked in

clamping blocks, and ready for crane barrel flange removal.

The crane is aligned with a dial gauge placed in the mill tool

holder. This update is part of the installation of late style D and

I model cylinders; afterward, the cylinder headspaces directly

on the frame.

About Late Style Cylinder

Assembly Replacements-

With early and intermediate D

cylinders no longer factory available,

only late style D cylinders are shipped.

Currently, the late D model #56557,

#56557N, #58801 [matte] .38 Spl.

cylinders and #56560B .22 LR

cylinder are supplied for replacement

use. These replace all D model

cylinders of .38 Spl. length.

Late I cylinders, after S/N 36190E,

directly replace all late .357 I model

cylinders. See figure 220. .38 Spl. I

cylinders are discontinued. E model cylinders are no longer factory

available in any calibre. And, Colt's

parts department indicates no future

plans for production.

The I #56721 stainless steel cylinder

began after change- over to late style

production, and is a direct

replacement.

Warning: Do not, under any

circumstances, alter an E model to receive any I .357 cylinder. Consider

the result if a .357 round was fired.

If original type D/E cylinder

replacement is necessary, and the

condition of the frame, barrel and

internal parts warrants the work, check

with suppliers of new factory

discontinued [and also used] parts,

such as GPC, West Hurley, N.Y.

Note: With any new or used

replacement cylinder/ratchet

assembly, always check for correct fit

at the ejector star, guide pins, and stem

spline, before beginning fitting work.

Pre-check and return any cylinder

assembly not in serviceable condition.


Set Cylinder Headspace

New D and I replacement cylinders

are built with extra long collars for

head-spacing in both early and late

model frames. Set as follows:

1. Install cylinder on crane, without

ratchet and stem. Make sure crane

lock is snug.

2. Close cylinder, measure headspace

at top rear of the cylinder. Make sure

there are no dents or nicks in the

cylinder or frame to alter the accuracy

of the measurement.

3. Trim the cylinder collar. Start by

removing only half the estimated

amount. Then, recheck headspace after each cutting pass. See figure 218.

4. Headspace is correct when a min.

headspace gauge will just fit between

the cylinder and frame [or recoil plate]

with light drag. See fig. 222 and

headspace table, Sect. I.

Set Cylinder Endplay

Once headspace has been set, cylinder

in-frame endplay is controlled by

ratchet shoulder length. See figure 223.

The ratchet shoulder must be square

and parallel with the frame. The

ratchet can't be free-hand cut. The best

way to adjust the shoulder is on a

surface grinder. But, with care, a good

job can be done at the bench with a

ratchet length adjusting fixture and a

flat mill file. See fig. 225A.

1. Install ratchet in cylinder, and

cylinder on the crane.

2. Then, estimate ratchet shoulder

reduction needed to allow the

cylinder to close.

3. Remove only half of the

estimated reduction amount.

Recheck cylinder fit.

4. Then, repeat steps 2 and 3, until

cylinder just closes.

Figure 222- Shows the cylinder in the frame with collar

trimmed to the correct minimum headspace. Headspace is

determined by gauge at the rear of the cylinder, as shown. The

collar can be trimmed to size on a lathe, or on the mill using a

piloted facing cutter. Use the "rule of halves when cutting critical surfaces.

Figure 223- Shows a new, uncut ratchet, set up in the frame for

shoulder measurement. Fit the ratchet shoulder to a near zero

in-frame endplay for match use. Approx. .001" endplay is

probably better for general service, or duty use. Always use the

"rule of halves" when adjusting ratchet height. See figs. 224 &

225A.


Figure 224- Shows one of two methods for trimming ratchet

shoulders to correct height. The above late style ratchet/stem

assembly has been magnetically chucked in a stem block, and

is ready for surface grinding to correct shoulder height.

Finished ratchets must be square and parallel with the frame's ratchet seat.

Figure 225- Shows a replacement cylinder fit to correct

headspace and with near zero in-frame endplay. With cylinder

work done, barrel- cylinder clearance, or gap, must be checked.

Frame stretch always adds to barrel/cylinder gap. Maximum

factory allowable gap is .008". If in excess of .008", barrel

must be re-qualified.

Setting Ratchet Length

Both of the ratchet fitting methods

shown in figure 224 and 225A

produce a well fit ratchet shoulder that

is flat, smooth, and free of burrs.

Surface Grinder Fitting-

The easiest way to trim ratchet

shoulders with late style, fixed stem

ejector- ratchets, when you have the

use of a surface grinder and magnetic

chuck, is to:

1. True a steel block, then drill a

.215" hole to receive the ratchet

stem. See fig. 224.

2. Dress and square a #100 grit wheel, then insert ratchet stem in

the steel block.

3. Energize the mag. chuck, reduce

the shoulder .0005" at a time,

until the correct ratchet length is

reached.

Bench Fixture Fitting-

With bench ratchet shoulder fitting

fixtures (see fig. 225A), adjustment is

made by hand with a flat mill file.

1. Clamp fixture between bronze

vice jaws. Install the ratchet in the

fixture.

2. Cut in .001" -.0005" steps. Adjust

height by selecting correct

elevating washer.

3. Install draw down screw and

secure ratchet.

4. Reduce shoulder height to flush

with the top of the hardened fixture with a flat, fine cut mill

file.

5. Repeat steps 2, 3, 4, until

shoulder length is correct.

Note: After cylinder/ratchet assembly

replacement, two other important

checks must be made:

1. Check hand-ratchet fit and

operation. Adjust long lug, or refit hand, if needed.

2. Check barrel/cylinder gap. See

figure 225.


Ratchet Lug/Hand Clearance

With E/I type ratchets, hand clearance

bevels are cut at the tips of the ratchet

lugs after the ratchet has been fit to the

cylinder body, and the ratchet shoulder has been finally adjusted and

trimmed to correct in-frame endplay.

Suggested cylinder in-frame endplay

for service duty revolvers should not

exceed .001". Competition revolver

endplay should be as close to zero as

possible.

E/I type ratchet lug tips must be

bevelled at approximately 45 degrees

for top hand cycling clearance. See figure 225B.

Warning: Adjoining ratchet lug

surfaces must not be hit or nicked

when filing clearance bevels.

1. Chuck the ejector star in a tool

maker's vice for this work. To

make fitting easier, position the

ejector star at an angle so that the

45 degree lug cut will be made

parallel to the top of the vice. 2. Use a barrette file positioned with

the dull side toward the ejector

star finger, and the cutting edge

well clear of the adjoining ratchet

lug surface.

3. Make each cutting pass at a 45

degree angle to the lug being cut.

Cut away from the ejector and

adjoining lug.

About D Ratchets-

Since the top hand stays engaged with

D style ratchets, no lug bevelling or

clearancing is required.

Figure 225A- Shows a hardened, precision ground ratchet

fitting fixture designed by the author for bench use, and built

by tool maker Bob Fillippini. Half-thousandth size elevating

washers provide correct ratchet fitting position. The ratchet is

filed and then stoned to exact length; fixture provides a 90 degree shoulder.

Figure 225B- Shows a close view of an E/I type ratchet and

correctly cut hand clearance bevels at the tips of the lugs. The

illustrations at right show ratchet lug clearance bevel details.

Always use caution when cutting clearance bevels. Do not

contact the ejector star or other ratchet lug surfaces when

filing.


Figure 226- Shows barrel damage conditions, in items 1, 2, 3, and 7, that make barrel replacement

necessary. The key word here is "damage". Without exception, the forcing cone problems shown in 1 and

2 are caused only by the combination of extreme temperatures and pressures. Some only moderately

eroded and/or edge cracked forcing cones may appear to clean up at .025"-.030"- or just at a one thread

barrel set-back. But, after this punishment, the unknown and questionable condition of the steel makes

trying to reuse such barrels an unsound, and possibly unsafe, practice.

The usual conditions that make barrel set back, or re-qualification, necessary are shown in items 4, 5, and

6. Barrel replacement is also recommended when the conditions in 4 and 5 are found in an extreme form- where setting the barrel back one turn from original factory installation will not clear the problem.

1. Forcing cone- is eroded, carburized, and brittle. This is caused especially by heavy over

pressure/temperature loads with slow burning powders.

2. Forcing cone- is cracked, blown, and/or internally damaged.

3. Barrel- is bulged or barrel bore has another internal irregularity such as a dimple or flattened area, etc

4. Altered forcing cone- has a compound, or double cut forcing cone angle- or the mouth opening

diameter has been cut too large.

5. Rear barrel face- is mis-cut on an angle- and more than can be straightened within maximum

barrel/cylinder gap clearance limit of .008".

6. Barrel/cylinder gap- is beyond factory limit of .008" maximum.

7. Bore- has internal rust, pitting, scratches, or other defects.


Remove Barrel

When barrel re-qualification or

replacement is necessary with

aluminium alloy frames, don't attempt

barrel removal in the field. Without

proper equipment, risk of cracking, or other damage, is too great. With steel

frames, barrel removal damage isn't

found very often. Invariably, steel

frame damage in the several examples

I've seen, has been caused by poor

tooling. The possibility of stuck

threads, and/or galling at the frame-

barrel torque shoulders make correct

barrel blocks and a good quality barrel

wrench an absolute necessity.

Don't attempt barrel removal with a

hammer or axe handle through the

frame- no matter who says its O.K.

1. When dealing with older models,

or resistant barrels, pre-soak the

barrel and frame in a thin mixture

of kerosene and oil for one or two

days.

2. Break thread and residue bonding

by sharply rapping the frame-

barrel junction with a plastic mallet.

3. Secure both the frame and barrel

in correct tooling. See figures 227

and 228.

4. Re-tighten tooling if barrel or

frame move or flex.

5. Apply even pressure in the

direction shown in fig. 228.

Lightly bump wrench handle

when needed to break torque.

Note: at this point, most barrels break shoulder torque and twist

loose. But, if still resistant, [or if

the frame feels springy with

medium wrench pressure] repeat

1-5 until barrel can be removed.

Warning: Do not use heat to break

barrel/frame bonding.

Figure 227- Shows contoured aluminium barrel blocks, used

for removing and installing Python and Diamondback style

shrouded barrels. These blocks can be used either in a barrel

press, or in a 5" jaw or larger bench vice, as shown, below. The

heavier the vice, the better. Use bronze, or steel angles to support the blocks.

Figure 228- Shows a frame being untorqued and twisted loose

with an MGW barrel removal wrench. Before attempting to

move the frame, the barrel must be tightly secured so that it

can't move. When using a bench vice instead of a barrel press,

prevent flex by using as large a vice as possible- and in no case

less than 5".


Figure 229- Shows barrel fitting points that are checked and

adjusted when installing a new barrel or setting back an

existing barrel. Frame clearance areas are shown at C. The

torque shoulder is shown at T, and the crush relief area at R.

Distance from the barrel shoulder to the first full thread can't

exceed .100".

Figure 230- Shows barrel torque shoulders on E and I revolver

frames. Shoulders must be flat and at 90° to bore centreline.

Level any galling marks and/or raised torque ridges to prevent

interference with the new, or re-qualified, barrel's shoulder.

Deburr and dress the inside edge to prevent thread and/or

shoulder galling.

Estimate Shoulder Setback

Some amount of shoulder adjustment

or barrel setback is always needed,

even when new barrels are being fit to

a frame. Re-qualifying a barrel

requires machining a one thread revolution setback from the shoulder.

With Colt's .5634-32 tapered (.017"

tpi) threads, a turn is approx. .035"

and 1/2 turn = .0175". With a 50/50

torque shoulder and crush relief area

ratio, barrel shoulders are final fit to a

hand tight contact at 30 to 45 degrees

remaining- or at approx. 1/8 to 1/10

turn to the 12:00 position. Match

barrels in .22 LR and .38 Spl. are best

fit at approx. 1/10th turn remaining to 12:00.

Frame Shoulder Preparation

The frame's barrel shoulder should be

checked and trued before threading in

the barrel and estimating barrel fitting

requirements. See figure 230.

1. If surface galling build- up is

present, carefully level the

shoulder with a 1/2" x 1/2" fine cut stone.

2. Level and remove raised torque or

compression ridges found at the

frame's barrel shoulder if the new

shoulder contacts the raised area.

Frame and Barrel Threads

Closely inspect both frame and barrel

thread condition before installing the

barrel.

1. Brush and solvent clean frame

and barrel threads.

2. Check barrel fit in frame. If

threads run tight, or bind, chase

frame threads with a .5634-32 six

flute finish tap.

3. If the barrel is still thread tight,

carefully clean thread bottoms

with a wire brush.


Lathe Cut Barrel Shoulder

The rule of halves is never more

important than with barrel work [i.e.

cut only half of your estimate,

recheck, re-cut, etc.]. Always proceed

carefully when cutting. New barrel shoulders will vary; some may require

trimming of only a few thousandths to

final fit. When too much is removed

from the shoulder, the barrel will be

loose, and correct torque point will be

beyond top dead centre.

The fixture shown in fig. 231 allows

easy barrel removal to check frame fit

between cuts.

Cut Crush Relief Bevel

With shoulder and threads fit, check

barrel for 30 to 45 degree hand-tight

position:

1. Then, return the barrel to the lathe

fixture and secure.

2. Set tool at a slight angle and cut

an .002" clearance bevel into the

inside 50% of the new barrel

shoulder.

Note: Don't overcut- for a correct

torque fit, about 50% of the correctly

adjusted barrel shoulder must remain

as cut- at 90 degrees.

Pre-clearance Barrel

1. Screw barrel in to hand tight and

estimate how much must be

removed from the rear barrel face to allow the cylinder to just close.

2. Then, adjust rear barrel face to

that measurement. Note: The

barrel will be longer than the

estimate when torqued to

position. I suggest pre-adjusting

in this way to prevent overcutting.

3. After trimming the barrel face,

trim off the last thread, then cut a

45 degree cylinder clearance

bevel at the outside barrel corner. See figure 232.

Figure 231- Shows lathe trimming the barrel shoulder to

setback position. With first barrel thread starting at .100" inside

the frame, threads are not adjusted forward. A chucked

centering fixture, aluminium driving doe, and live centre are

used here. This fixture allows easy removal and barrel return

during fitting-checking steps.

Figure 232- Shows the barrel shoulder after set back

adjustment. The three remaining steps are:

1. Cut an approx. .002" max. depth crush relief bevel into the

inside 50% of the shoulder.

2. Pre trim the rear barrel face, cut the cylinder clearance

bevel, and remove last thread. And,

3. Mill shroud about .010" for frame clearance.


Figure 233- Illustrates final hand-tight position for barrels with

correctly cut shoulders and crush relief bevels. The 90 degree

portion of the barrel shoulder should agree with the frame. Fit

should not vary more than .001", and is easily checked with a

feeler gauge. Use a good anti-seize compound when installing

barrels.

Figure 234- Shows the barrel installed in barrel blocks and the

barrel wrench reinstalled on the frame. Barrel vice and wrench

fittings must be tight to prevent slippage and torquing past top

dead centre. Estimate distance the wrench will travel. Staying

short of that amount until the final adjustment helps prevent

over-twisting.

Final Check Barrel Fit

Before torquing the barrel, make the

following checks:

1. Feeler gauge check the 90 degree

portion of the barrel shoulder

against the frame. There should be no more shoulder variation

than .001". See figure 233.

2. If high spots are present, locate

with Dykem Blue. Then, stone

high areas until surface is within

.001" limit.

3. With shrouded barrels, check the

upper non-relieved half of the

shroud for frame bind. Lightly file

or stone the surface to prevent

galling. 4. With rib type barrels, lightly stone

the top [frame side] of the rib for

clearance. Leave the bottom half

intact- it's part of the shoulder.

Torque Barrel

1. Always begin by applying a

coating of commercial antiseize

compound [or a paste made 50/50

of graphite and grease] to barrel

and frame shoulders, and barrel threads.

2. Screw the barrel into the frame

until it is hand tight.

3. Install barrel in blocks, and

reinstall barrel wrench.

4. Tighten the barrel wrench on the

frame, and the barrel blocks in the

barrel vice.

5. Then, rotate the barrel wrench,

torquing the barrel- frame joint

carefully, a little at a time, while watching the position of the frame

vs. the front sight. See figure 234.

Warning: If the frame is over torqued

and taken beyond the correct barrel

alignment point at 12:00, or top dead

centre, the barrel then must be

removed and refit.


D, E, and I Model Forcing Cone Data

Mouth Mouth

Model Calibre Min. Max.

D .22 LR .238" .243"

D .32 NP .330" .335"

D .38 Spl. .370" .383"

E .38 Spl. .363" .378"

E .22 LR .238" .243"

E .22 Mag. .238" .243"

I .38/.357 .370" .376"

Colt's D, E, and I model forcing cones are factory cut on a .160" taper per

inch. This works out to about 9°. These cones use a 9° included angle forcing

cone cutter. However, the matching 9° tapered plug gauge, shown at right,

isn't used to check angle, at all, but instead, to check mouth opening diameter. Ideally, when the correct plug gauge is used, forcing cones should

gauge midway between the maximum gauge level at 1, and the minimum

gauge level, at 2. Mouth diameter should not exceed maximum gauge

diameter. As an option after gauging, an 82* cutter can be used to lightly

relieve sharp edges at the forcing cone mouth.

Illustration is exaggerated for example.

Forcing cone mouth diameter, at "D", is critical, and must not be greater than, or less than the factory

specified minimums and maximums for the model and calibre as listed above. Bullet deformation is kept

to minimum in revolvers with correct forcing cones.

Figure 234A- Illustration shows barrel/forcing cone cross section, forcing cone angle and mouth diameter

caution. In revolvers, the diameter of the forcing cone mouth opening is more important than the exact

forcing cone angle.


Figure 235- Shows a frame with replacement barrel installed.

The rear face was left long for final adjustment of

barrel/cylinder clearance. A facing cutter is shown installed in

the barrel. For a correct surface finish, select a cutter a bit

larger than barrel face O.D. With hand tooling, use light cutting

pressure to prevent scalloping.

Figure 236- Shows cutting a forcing cone using a Forcing cone

cutter, bore centering pilot, and guide. Cut slowly, with light

drawing pressure to avoid catching a rifling lands and

chattering the cut. Remove very little metal with each cutting

pass. Check mouth opening frequently with a tapered plug

gauge. See figure 237.

Set Barrel/Cyl. Clearance

When barrel installation or re-

qualification is complete, and cylinder

headspace and endplay are at

specification, barrel-cylinder clearance

can then be set. See figure 235.

While a file can be used for this work,

some gunsmiths have difficulty

keeping the barrel face parallel with

the cylinder. For this reason, I suggest

using a piloted facing cutter. With

careful handling, this tooling will cut

the face smoothly and exactly at 90

degrees to bore centreline.

Factory min. clearance is .003" and max. is .008". With re-qualified or

new barrels, I suggest a clearance of

.005" with the cylinder at near zero

endplay. If clearance is set at or below

.004", firing residue may necessitate

too frequent cleaning. Some match

wadcutter shooters set clearance just

at the limit of .008" to allow for bullet

lube build-up.

Cut Forcing Cone

A correctly cut forcing cone preserves

basic accuracy by preventing

excessive bullet deformation. Rough

cut, off centre, and too large or small

cones destroy accuracy. Key- holing

can be caused by over size mouth

openings and/or compounded cone

angles.

D/E/I barrels are made with 9° forcing

cones. See data on previous page. With custom barrelling, a steeper 18°

cutter is probably best for jacketed

bullets, while an 11° is near optimum

for hollow base wadcutters. Forcing

cones cut at 9°, 7°, or 5·5° are more

gradual, and are cut longer to obtain

the correct mouth diameter.


Cut and Gauge Forcing Cone

1. Begin by gauge checking the

existing forcing cone.

2. When angle is unknown, hand

spin [dry] brass lapping heads

inside the cone, trial and error, until full brass contact identifies

the angle.

3. Install the rod, guide, and the

correct pilot and cutter.

4. Slowly rotate the cutter,

maintaining a light and very even

drawing pressure. Clean and

gauge the cone between cutting

steps. See figure 237.

5. Repeat cutting/gauging steps until

the desired mouth diameter has been reached.

Note: As an accuracy step, since

barrels vary somewhat, the mouth of

the finished forcing cone can be set so

the lower level of the plug gauge rests

flush with the barrel face. Thereafter,

the mouth can be enlarged, as

necessary. But, for general use, the

best setting is just at mid-point of the

gauge. See figure 237.

Lap Forcing Cone

Polishing forcing cones to a high gloss

serves no practical purpose. However,

the walls should be lapped just enough

to remove cutting ridges. Silicon

carbide compounds, available either as

a premixed paste or powder, are very

workable; the abrasive sticks to the

much softer brass lapping head,

making it a precision sander. A #320 or #400 polish will reduce the

tendency toward lead build- up in the

cone, and make cleaning easier. See

fig. 238. Note: After lapping, clean the

forcing cone and barrel thoroughly

with kerosene and a brass brush.

Figure 237- Shows a tapered plug gauge used to check forcing

cones. The gauge shown measures mouth size when a 9°

included angle cutter is used. Other cutter angles require

separate gauges. The gauge must not drop past the upper level

in a finished cone. Mouth opening is ideal when gauge stops

midway between gauge levels.

Figure 238- Shows a brass lap installed in the forcing cone after the final gauging and cutting step. The lapping head must

match the cutter (i.e., use only a 9 degree lap, after a 9 degree

cutter). Brush apply a thin coating of #320 or #400 lapping

paste directly to the lap, to prevent the excess from entering the

bore.


Figure 239- Shows a barrel crown that is both nicked and

dented. Even the smallest nick at the edge of the bore will

engrave bullets, allow pressure blow-by and deflection, and

affect accuracy to some extent. "By eye", and freehand

attempts at re-crowning nearly always make crown problems

worse. Use correct tooling.

Figure 240- Shows a mill set-up for installed barrels using a 45

degree, piloted re-crowning cutter. For this work, the barrel is

held in a contoured aluminium clamping fixture. The hand

cutter with self aligning pilot, shown below, is similar in

design. When used carefully, this tool will produce acceptable

results.

Recut Barrel Crown

Accidents, careless handling, and

improper transport, etc., can create a

wide variety of exterior nicks, dents,

and general damage. Barrel crown

damage is one of the worst of this category. See fig. 239. Once barrels

and frames have been assembled, re-

crowning on a lathe is more than a

little difficult. For this reason, most

tooling available to the armourer is

self-piloting and designed to be used

after the barrel has been installed.

1. When re-crowning on the mill,

first align the barrel and secure it

in an aluminium clamping fixture. Then centre the cutter pilot [usual

pilot- bore clearance is .002-

.004"] in the bore. This produces

a perfect crown and provides

room for chip clearance.

2. Lube, and cut the crown slowly,

until the dent or nick is just

removed. Trim, at least, to the

bottom of the rifling grooves.

3. Remove the cutter and install a

brass lapping head of the same

angle. 4. Brush the lap with a thin coating

of #400 silicon carbide lapping

paste and lightly polish the crown.

5. Unclamp the revolver. Clean the

bore with a brass brush and

solvent. All traces of lapping

compound must be removed from

the bore. Note: When using hand

type cutters, point barrel down-

ward, clamp barrel between

aluminium vice jaws, then lube from the inside. This prevents

irregular hand cutting chips from

getting between pilot and bore

and scratching the interior.


Figure 241- Shows the plug gauge, or range rod check. Before gauging, barrels and cylinders must be

clean- and 100% free of lead, copper fouling, or other residue. Pre-check crane alignment with a thimble

gauge before making this check. Since this is the basic test for cylinder/barrel misalignment, the crane

must be perfectly straight. Plug gauge check as a routine part of barrel work, cylinder replacement, and always with accuracy related problems. Plug gauges detect irregularities, only, and cannot measure or

check barrel diameter.

Bore (and lands) diameters can vary somewhat in D, E, and I models. Factory lands specifications at the

muzzle for .38 diameter D and I models run between .345" min. and .348" max., and .346" min. and .347"

max. for E models. Since lands diameter determines gauge head size, a variety of range rod heads should

be stocked to accurately check barrel-cylinder alignment.

Lands I.D. determines test gauge size in any given revolver. For example:

If the lands measure .348", a service diameter gauge head would measure .0015" less, or .3465". A match diameter gauge would measure .001" less, or .3470".

At the opposite extreme, with the lands at .345", -.0015" would give us a .3435" service gauge head, and

minus .001" a .3440" match gauge head, and etc.

It is unrealistic to expect a service duty revolver to pass the match diameter gauge test with the extremely

small gauge clearance involved.

With straight cranes, even small things such as a slightly loose (undersize) stem, or flaring around the

serial number inside the crane, can hold the crane slightly off centre and cause interference as the plug

gauge enters the cylinder. In some instances, these cranes will just allow thimble gauge/latch pin tunnel

entry.

A worn cylinder bolt and slightly long bottom hand and/or low ratchet lug may also cause gauge

interference. A loose latch pin can add to this condition.

Compression dimpling inside the bore at the barrel shoulder/frame joint, and/or slight flattening from

squeezing the barrel in a bench vice, can cause gauge interference inside the bore. Avoid compression

dimpling by careful barrel thread and shoulder preparation before installation, and by always holding

barrels with contoured blocks. Always pre-test replacement barrels before fitting.


Figure 242- Shows a close view of a factory tuned Python model action. When examining custom factory

actions, you will find that fine tuning is basically just a matter of degree. This work involves careful hand

fitting to a high level of action smoothness, precision sear and strut work, and tuned, lightened springs

and trigger pull for .38 Spl. match and competition use.

Tuning Factors Necessary in Match Actions-

1. Instant bolt pick up and correct bolt drop timing.

2. Correct hand/ratchet fit and "equal" ratchet lug surfaces.

3. Perfect crane/cylinder/barrel alignment.

4. Barrel and cylinder must pass the plug gauge test. 5. Single action sear set for not less than minimum safe pull, without push-off.

6. Strut pick-up surface at top of sear is polished for smooth D.A.; top of hammer toe, and S.A. pick-up

surface under sear is polished for smooth S.A.

7. All action drag factors are eliminated. See figure 243.

8. Mainspring tension is correctly adjusted. See figures 173 and 174.

Also, in factory tuned Pythons, cylinder bolt springs are slightly shortened.

Warning: When mainsprings are adjusted to minimum factory trigger pull specification, tension is

lowered on both sides of the spring. But, the most obvious effect is that mainspring pressure is less at the

trigger. When mainsprings are adjusted to lower tension, or when lighter custom springs are used, the

force of firing pin impact is also reduced. Lightened mainsprings and correspondingly light trigger pull

make match tuned actions impractical and unsuitable in both field and service duty use for two basic reasons: the possibility of hammer release before the revolver is on target; and, secondly, lower main-

spring energy may deliver questionable performance with standard ammunition.


Figure 243- At right, shows possible action drag areas that may require adjustment or polishing to

improve overall action smoothness for match or competition use. Colt has a long standing reputation for

superb "out of the box" production revolver actions. But, custom tuning takes action smoothness to the

point of near perfection.

After final tuning the S.A. sear, D.A. strut, and adjusting mainspring tension, the rest of action tuning is

simply refinement, i.e., the careful elimination of factors that cause drag. Drag and friction are always additive; a little friction here, a little drag there, can add up to a fair amount of resistance. Action drag

areas, and contributing causes of friction, are listed in the order usually found:

1. Hand- when incorrectly bent, insufficiently edge chamfered, etc., the hand may drag, dig into the

frame, or catch the sideplate. When a hand is too thick, or has rough sides, it will bind or drag

between frame and sideplate.

2. Hand- when let out too far, the forward point of the top hand may extend past the ratchet recess and

drag as the cylinder is opened and closed. The hand may interfere with shell heads when front surface

fitting is incomplete.

3. Hand pivot pin- if bent, or damaged by vice jaws, can make the hand sticky.

4. Bottom hand- when long, can hold single action sear position low and cause the hammer to drag or bump the sear on release. Caution: this also can be caused by a long sear extension.

5. Hand's tensioning cam- if mis-cut at a wrong or reverse angle, can drag, back up, bind the rebound,

and stick the trigger.

6. Hand's rebound slot- when rough, the surface can drag or bind the side of the rebound lever. This also

makes the trigger sticky.

7. Rebound lever- when bent, rough, and/or too wide, the lever can drag the frame, sideplate, and hand-

and may also prevent trigger return.

8. Rebound lever- if misfit, the hammer seat may rebound the hammer too far forward, and cause safety

drag and/or safety interference.

9. Hammer- may drag the frame or sideplate if too wide, and/or when the sides and skirts have been

unevenly polished. When the hammer pin hole is tight, the hammer may drag on the pin.

10. Hammer skirt- inside edge may drag or catch the safety. The hammer skirt may need slight chamfering on the frame side for safety/link pin clearance.

11. Frame- high spots, ridges, and/or burrs may drag the hammer or trigger. A nick or burr at the inside

of the sideplate joint may drag the hammer.

12. Frame- a sharp edge or machining ridge at the ratchet recess corner can interfere with the hand and/or

ratchet. Safety recess burrs may drag the safety.

13. Safety- high or misfit link pin heads may drag. The safety lever may drag against the trigger. The

upper safety may drag inside its frame recess.

14. Latch pin- the back of the latch pin may drag against the upper safety as it cycles.

15. Trigger- when the bearing shoulder is too wide on the left side, trigger will drag between frame and

sideplate. Without side clearance, the right side of an I model sear may drag the safety lever. If the

trigger pin hole is tight, the trigger may drag on the frame pin. 16. DA strut- a flattened point and/or incorrect strut let-out can produce rough DA release. Also, when

the strut is tight or sticky in the hammer body, the strut can slow or stop trigger return.

17. Mainspring- excess tension overloads, and drags, the SA sear point. A sharp bottom spring end may

drag the rebound.



A Few Last Words About Action Tuning and Custom Work . . .

Times have changed for the craftsman. These days, if you do action tuning and custom work, you brush

shoulders with a bad dream come true called product liability, in much the same way as would a

manufacturer. If you are not already familiar with this subject, it might be worthwhile to talk it over with

your attorney. Product liability could be defined as "the modern road to riches." With the help of crafty

lawyers, more and more jerks are now retiring early- and on your nickel.

1. Remember that custom gunsmithing is creative, and therefore different than basic mechanical repair

work. When you enter this field, you are the designer.

2. Don't do patch work, ever. When you know that a trigger, barrel, cylinder, frame, etc, actually

requires replacement- replace it and be done with it.

3. When doing machine work, make all set-ups carefully and on an individual basis. Remember that,

with mass produced products, no two are precisely the same. Always recheck the set-up, before

cutting.

4. Never alter a safety system. Replace mis-matched safety parts. And, always recheck safety function,

since you may be sued for any mishap, thereafter.

5. Do only custom work that you know is safe and properly useful. Turn down odd requests for things such as extremely light trigger pulls, cutaway trigger guards, and etc.

6. Turn down every "opportunity" to perform low quality work. Whatever work you accept, do it well.

However small, every job you do becomes a part of your reputation.

7. Do only the highest quality custom work, and price it accordingly, as quality work. In this way, you

will develop a high quality clientele.

8. Be selective, work only for those who can appreciate fine work. Remember that high quality custom

gunsmithing goes beyond craftsmanship; somewhere along the line, it becomes an art form.

The very best things have always been made by hand: the finest automobiles, the best shotguns, and the

most accurate target revolvers. Well crafted firearms, when properly cared for, will last and can be

enjoyed by generations.


Figure 244- Shows a match tuned Colt Python set up in a Ransom Master Series Machine Rest with I

frame grip inserts. The optional base shown provides windage adjustment. -Machine rest photo courtesy

Ransom International Corp.

Set sights on the vertical centreline of the target and at the 6 o'clock hold position. Minimum test firing

distance is 50 feet. The 6x3 test, discussed earlier, uses standard factory, or service ammunition. The 6x6

match accuracy test uses match grade wadcutter loads.

Six rounds are fired through each chamber. The cylinder is marked with a white grease pencil, and that

chamber is always fired first. Uniformity (or repeatability) is the rule: ammunition must be from the same lot so that all bullets, cases, powder, primers and shell crimp are the same.

Check all six targets. Points of impact should be well grouped, similar, and with no more variation than

would be standardly produced by the ammunition used. Problems having to do with the sights, or a

specific chamber or ratchet lug, etc., are easily detected. Also see figures 178 and 241.


PARTS DIAGRAMS

The following intermediate and late Colt D, E, and I model parts diagrams were used in the author's

original manuals to provide a quick and easy reference at the bench. In keeping with the original shop

manuals, we have included the same parts diagrams here.

These drawings provide typical examples of model types, but may not exactly depict all features of a

specific variation at the bench. Individual parts drawings do not exist for every sub-type and model

variation. This is particularly true where barrel and cylinder variations are concerned.

At the back of this section, for reference, we have included model specifications and parts illustrations on

many of the early style Colt small and medium frame double action revolvers (pre-D, E, and I model

designations). These drawings show the basic similarities between early, intermediate, and late models.

Although this shop manual does not cover Colt's large frame, double action revolvers, parts illustrations

and specifications for the New Service Model (the M1917 U.S. Army Model is basically the same) are

included to show the close design similarity between large frame and pre-D, E, and I designation small

and medium frame revolvers.


Parts Description

1. Barrel 29. Latch Pin

2. Cylinder Bolt 30. Latch Spring

3. Bolt pivot Screw 31. Latch Spring Guide

4. Bolt Spring 32. Mainspring

5. Crane 33. Ratchet

6. Crane Bushing 34. Rear Sight Blade 7. Crane Lock Detent Plunger 35. Rear Sight Det. Ball

8. Crane Lock Screw 36. Rear Sight Det. Spring

9. Crane Lock Spring 37. Rear Sight Elev. Screw

10. Cylinder Assy. 38. Rear Sight Elev. Screw Pin

11. Ejector Rod 39. Rear Sight Leaf

12. Ejector Rod Head 40. Rear Sight Leaf Elev. Spr.

13. Ejector Spring 41. Rear Sight Leaf Pin

14. Firing Pin 42. Rear Sight Windage Screw

15. Firing Pin Spring 43. Rear Sight Windage Spring

16. Firing Pin Stop 44. Rebound Lever

17. Front Sight Blade 45. Rebound Lever Pivot Pin 18. Front Sight Pin 46. Safety (Upper)

19. Frame 47. Safety Lever

20. Hammer Assembly 48. Sideplate

21. Hammer Pin 49. Sideplate Screw (Front)

22. Hammer Stirrup 50. Sideplate Screw (Target)

23. Strut Pin 51 & 52. Stock Assy.

24. Hammer Strut 53. Stock Pin

25. Hammer Strut Pin 54. Stock Screw (also Target)

26. Hammer Strut Spring 55. Stock Screw Nut

27. Hand 56. Trigger

28. Latch 57. Trigger Pin


Python and

Police Python

.357 Magnum & .38 Special


Trooper

(Original Model)

.357 Magnum & .38 Special


.357 Magnum Model

.357 Magnum


Officer's Model Match

.38 Special & .22 L.R.


Official Police and

WW II Commando Model



Diamondback



Police Positive Special

.38 Special & .22? L.R.


Detective Special,

Agent



Cobra

Viper

.38 Special


The Colt Elliason adjustable rear sight was designed like other match competition type sights, so that the entire back of the sight is an enlarged rear blade. The blade is canted slightly rearward to shadow and

darken when held on target. The entire rear blade moves for windage adjustment. Point of bullet impact is

moved in the same direction.

At this time, aside from the elevation screw and spring, given above, no other Elliason sight part numbers

are listed, or are available for field replacement.

The Elliason rear blade, windage screw, and windage screw nut are permanently staked after factory

assembly. For this reason, if rear blade or internal sight repair work becomes necessary, the sight must be

shipped to factory service Tor inspection and repair.


FACTORY DISCONTINUED PARTS SECTION

With all model variations considered, I would estimate that there are probably more than a million early and intermediate Colt double action revolvers either still in service or being kept in drawers. Based on

production numbers, the majority of these revolvers will be pre-D and E designation small and medium

frames, as well as large frame New Service Models.

With these numbers in mind, we have included the following discontinued parts section and early

specification sheets for the purpose of model/type identification- and, as well, to advise owners,

collectors, and revolversmiths of an excellent source for Colt factory discontinued parts for many of these

models.

When parts are needed for early and intermediate Colt double action revolvers, check with Gun Parts

Corporation, West Hurley, New York. While GPC is probably the world's largest supplier of discontinued parts, they tell us that inventories change, and that all parts may not be available at a given time.

Early and Intermediate Colt Double Action Revolvers:

Pocket Positive Army Special

Police Positive Camp Perry Model

Police Positive Special Officer's Model

Banker's Special Official Police, Early

Detective Special, Early New Service

Agent, Early New Service, Target

Commando, WWII Model M1917, U.S. Army, etc.



Figure Q- The above page is reprinted from an early Colt Parts Catalogue, circa 1920, and features rare

phantom views of Colts' long discontinued M1917 large frame revolver and 1903 Hammerless Automatic

Pistol. The M1917 and New Service model revolvers are much like larger editions of medium frame

Army Special or Official Police revolvers. -Courtesy Colt Firearms


Figure R- Specification from early Colt Catalog. –Courtesy Colt Firearms


Figure S- Specification from early Colt Catalog. –Courtesy Colt Firearms



Figure T- Specification from early Colt Catalog. –Courtesy Colt Firearms


Figure U- Specification from early Colt Catalog. –Courtesy Colt Firearms


Figure V- Specification from early Colt Catalog. –Courtesy Colt Firearms



Figure W- Specification from early Colt Catalog. –Courtesy Colt Firearms


Figure X- Specification from early Colt Catalog. –Courtesy Colt Firearms


Figure Y- Specification from early Colt Catalog. –Courtesy Colt Firearms



Figure Z- Specification from early Colt Catalog. –Courtesy Colt Firearms


Figure AA- Specification from early Colt Catalog. –Courtesy Colt Firearms


Figure BB- Specification from early Colt Catalog. –Courtesy Colt Firearms





-Drawings,. –Courtesy Colt Firearms


Colt Firearms

-A Heritage of Fine Craftsmanship

-Colt Python product photo courtesy Colt Industries, Firearms Division

The Colt logo is a registered trademark of Colt Firearms

Documents

Colt Revolvers Workshop Manual Vol 1 - Jerry Kuhnhausen.pdf