Clean that Revolver now and then


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Accompanying article from the current issue of The Fouling Shot has more detailed info:

Wheelgun 101

Mechanical and Safety Inspection of the Double-Action Service Revolver

Based upon common questions I receive from readers, and having to repeat, what used to be common knowledge, it appears that most shooters today lack any basic understanding of double-action revolver inspection. A year or so ago Dave Reiss wrote an excellent article on basic tune-up of the S&W revolver, in FS246-18, which I recommend very highly. [Another article by Dave in the current issue 261-11 explains the tools of the revolver smith and how they are used].

Below I've attempted to explain duty revolver mechanical inspection and reconcile differences between what I was taught at Ruger, from Dave’s article which was specific to the S&W. This guide is for the non-professional, but covers the aspects of revolver annual inspection as it was practiced by police armorers back when your life depended upon your service revolver going "bang~!" every time. So, pay attention, Grasshopper and you will know how to inspect a used gun before buying, and be more knowledgeable than most people working behind the gun shop counter:

Open the cylinder, keeping the muzzle pointed safely into the clearing barrel.

Confirm that all of the cylinder charge holes are empty and that the bore is clear.

Actuate the ejector rod fully inward. Hold and examine the underside of the extractor and contact area of the cylinder for unburned propellant residue. Brush clean if any is found present. If a revolver used in sandy areas, sand may indeed collect in there as well.

Confirm proper function of the thumbpiece when releasing and opening the cylinder.
S&Ws push forward, Colts pull backward, Ruger pushes inward.

Inspect the firing pin hole in the recoil plate/frame bushing for peening for burrs.

Gunsmith or armorer needs to stone off any burrs around firing pin hole and to restake or replace the recoil plate or firing pin bushing if loose, cracked, damaged. Brownell’s sells the correct tool for doing this.

Press on the center pin which protrudes at the center of the extractor of an S&W or Ruger at rear of cylinder, to verify center free pin movement and positive return.

Visually inspect the front end of the S&W center pin for peening. Stone off any burrs.

With the cylinder open, spin the cylinder and watch the end of the ejector rod for wobble.

Check with the fingers that ejector rod is tight, and not loose on threads.

Verify that the ejector rod functions correctly at its full stroke and returns positively.

Close the cylinder, grasping with thumb and forefinger.

The cylinder must not strike the barrel when closed!

Confirm that both front and rear of the center pin on S&W or older Ruger Six series lock positive fore & aft as cylinder is closed. Inspect crane lock function lock on later Rugers.

Visually inspect fit of yoke/ crane at front of frame for gaps, which could indicate misalignment.

Check barrel-cylinder gap with feeler gage inserted completely through the frame opening between cylinder and barrel.

PASS is the dimension when protruding out both sides of frame window between barrel and cylinder, which does not impair a complete rotation of the cylinder by pulling trigger through DA six times.

Min PASS dimension is 0.003", because a tighter gap may bind cylinder when gun gets hot or if shooting "dirty" ammo, such as black powder or lead bullets which are too hard, undersized and inadequately lubricated...

HOLD is the dimension when protruding out both sides of the frame window between barrel and cylinder, which binds rotation so that resistance is felt in a DA trigger squeeze.

Max. hold is 0.008" on a new gun when measured with "rear gage" or fired brass in cylinder. Customer service max. is 0.009" if cylinder end play is not excessive.

At 0.010" cylinder gap the usual factory repair procedure is to fit a new "long" cylinder. Gunsmith method is to set the barrel back a thread and refit after removing end shake, stretching crane arbor on S&W or Ruger if necessary, or swaging a Colt cylinder bushing.

Feel cylinder fore & aft for longitudinal movement. On Colts this check should be made with the trigger held to the rear in the fired mode, then cylinder lockup should then be solid.

End shake is measured comparing the HOLD dimension measured twice, with and without empty brass or "GO" headspace gages in the chambers, or alternately with a 0.059" blade gage inserted between rear of cylinder and recoil plate.

The least cylinder movement most people can “feel” is about 0.002.” If an S&W or Ruger and the cylinder "feels solid" with empty brass in the chambers, the gun is OK.

Colt max. end play is 0.003, so if there is ANY felt end shake the gun is out of spec.
Measure the difference between "pass" cylinder gap dimension taken twice with and without brass in cylinder.

If any sideways cylinder wobble or hesitation of center pin to lock fore and aft, disassemble cylinder from the yoke, check crane or yoke alignment with gage and correct.

Visually inspect locking bolt notches of cylinder for peening, particularly caused by cylinder backspin in S&Ws from heavy loads, such as +P in J-frame guns or +P+ in K-frame!

Pull revolver action through vigorously DA while watching for positive trigger return and positive lockup of cylinder stop/bolt at each charge hole, before hammer drops, noting any failure to "carry-up," or any "throwby" i.e. over-rotation of the cylinder failing to lock up and rotating past a chamber, or sideways wobble.

Throw-by test should always be done by a rapid DA pull; because many times an empty cylinder lacks the rotational momentum of a much heavier full cylinder and won’t show a throw-by unless the trigger is pulled quite rapidly.

The carry-up test needs to be done slowly, as a rapid pull can mask a “DCU” (factory term for doesn’t carry up) problem.

Visually check bolt or cylinder stop function at every charge hole and finger-wiggle cylinder for side-wobble at each charge hole.

Cock each chamber SLOWLY in SA with the weight of gun resting in the palm of hand for drag. Note any failure to "carry up" and for bolt or cylinder stop to engage locking bolt notches prior to full cock.

Check hammer for push-off from the full cock position.

Drop hammer, hold trigger back and check cylinder for wobble both sideways and fore & aft

With hammer down and trigger held back again check cylinder wobble, observe hammer nose driven protrusion and retraction below flush with recoil plate as trigger allowed to rebound forward.

"Tightening up" a revolver action to adjust timing/indexing may be as simple as peening a Colt hand a bit longer so that a charge hole which is "slow" carries up.

Factory procedure to correct DCU on S&W is to replace the hand with a slightly wider one, so its top comes closer to the inside of the hand slot. Thicker hands are sold for just that purpose. A factory K-frame hand is 0.091-0.095” thick, measured just below the hook. Most often a replacement hand 0.001-0.002” wider will correct the problem. Power Custom makes wider hands up to 0.105,” which require gunsmith fitting.

A gunsmith method to correct timing on older guns, particularly Colts, for which parts are not available, is to bend the band slightly. Rotate the hand medially toward cylinder centerline to speed up timing. Conversely to delay it. Sometimes the frame window needs to be opened just a wee bit to get timing correct. Brownell’s sells an offset file that makes this job much easier and precise. If that doesn’t solve the problem it’s probably because the ratchet cam surfaces have worn below the level of the hand slot and must be replaced.

S&W and Ruger timing adjustments should always be made AFTER correcting end shake and squaring the end of the cylinder yoke or crane arbor. On S&Ws the end of the yoke is frequently out of square with the axis of cylinder rotation. Again, Brownells provides a nice tool for K, L, and N frames. For J frame, I improvise with a muzzle squaring tool.

US Customs and Border Patrol experience in the early 1980s was that K-frame S&W .357s of that era required returning to the factory for a new extractor every 1500 rounds of 357 Magnum loads, while Rugers went 10,000 rounds with Remington and Winchester full charge .357 ammunition with no repairs or parts replacements being required. The associated lockwork on a Ruger Service Six, Speed Six or Security Six are hard all the way through and I’ve never heard of one going out of time in service. An endurance test I am personally aware of conducted at FLETC by Mark Humphreville, an Aberdeen Proving Ground Certified Small Arms Test Director, for the US Border Patrol and US Customs ran six Ruger Service & Security Sixes 10,000 rounds each of full charge 357 Magnum duty ammo (125 gr and 158 gr) without going out of time.

Always visually inspect barrel forcing cones on revolvers. Per a statement by Smith & Wesson Factory QA Rep, (1983 time frame) at a meeting at the Federal Law Enforcement Training center with US Border Patrol personnel, S&W 357 K frame barrels were likely to crack in the 6:00 region after about 3000 full charge .357 rounds and required replacement.

A wobbly cylinder is usually caused by worn locking bolt notches and is usually corrected by fitting a new cylinder stop or bolt and sometimes by peening the locking bolt notches in the cylinder to reduce side play. In severe cases replacing the cylinder may be necessary, particularly on abused older Colts.

Reducing cylinder end play of a Ruger or S&W involves stretching the crane to hold the cylinder back. Supporting the inside of the crane arbor is important when stretching to prevent collapse during the procedure. Stretching the also increases cylinder gap, which if it then becomes over 0.008" then requires either refitting a "long" cylinder, or setting the barrel back a thread and resetting the gap to factory specs. Above not applicable to Colts; the gas ring, which is integral to the cylinder, must be swaged to lengthen. In extreme cases, it is machined off and a bearing ring fabricated to take its place.

A simple clean, inspect and tweak not requiring fitting any replacement parts runs $100-150 most places today.

A full duty refurb which includes any machine work needed to straighten a bent frame (caused by using the gun as an impact weapon against a hard-headed subject), or setting the barrel back and refit to correct lose cylinder gap over 0.008", realigning the crane, correcting end shake, adjusting timing to correct a DCU (doesn't carry up) condition, replacing worn springs, targeting and checking hammer throw and striker indent on the government gage with copper crusher typically runs $250-300.

Today you rarely find gunsmiths who actually MEASURE striker indent on carry guns! That's because while you can buy the gage holders and their drawings are in the public domain, the "C" size .225x.400" annealed coppers are provided only to the government and their contractors and cost $2 apiece in minimum lots of 500, the last time I bought any. So the civilian and PD gunsmiths who did this for a living developed a "work-around."

For checking hammer fall, an expedient screening check before test firing with duty ammo, to be done only after all mechanical corrections to action have been completed, is to loop a string around the hammer so that you can attach a trigger pull scale. Pull the trigger to start the hammer moving. Pause midway. Attach trigger pull gauge. Pull hammer back note weight just before it locks into single action. You want 50+ ounces for reliability. Balance between hammer spring and trigger return spring are important. A light trigger return spring and heavy hammer spring is a recipe for mechanical lockup in the action. Check for this during cylinder timing check. Trigger return should not be sluggish. If so, it indicates that action springs are imbalanced and trigger return spring likely needs replacement.

Most important on an S&W is that the strain screw in the front of the grip frame is tight, and that the screw has not been shortened to lighten trigger pull! On a carry gun that light action can get you killed, because it reduces hammer fall and may cause misfires. All .357 Mag. and most +P defense loads today use heavier-cupped primers to prevent the primer cup from flowing into the clearance around the hammer nose in the recoil plate. This would cause hard cylinder rotation.

Heavier cup primers are less sensitive, and more prone to misfires if you have a gun with lighter after-market springs to reduce DA trigger pull, inexpertly converted to DAO with shorter hammer-throw, or a bobbed hammer.

If unable to measure striker energy (minimum 0.010" Cu indent in DA on the size "C" copper in the gov't gage) test fire a full box of 50 rounds of your carry ammo in DA. Accept if ZERO misfires, Retest if "1" misfire, reject if "2". If firing a second sample of 50 rounds runs OK, the gun is OK, but understand it is only 99%... If you get 2 misfires in 100 rounds don't carry the gun until you change ammo and re-test or repair it.

Check driven protrusion of hammer nose or firing pin, any pitting or damage to tip, replace any weak or modified springs.

Finding a guy who will discuss striker indent and hammer fall with you and who can explain what he does to assess it is a much better "filter" than some school certificate on the wall. Unfortunately the coppers aren't sold to the gunsmith trade, only to those who do federal contract work. SO if your gunsmith asks for a full box of your expensive carry ammo to function test, THAT is a good thing. If he can actually show you the gage holders and his $1000 box of coppers and explain their proper use, this means you have an APG or FLETC certified revolver inspector who was trained at the S&W, Colt or Ruger factory especially for the Feds, and the guy is absolutely "golden" and you should rub his bald head for good luck as if it was the Buddha's belly!

If a revolver rework requires heavy duty cleaning, such as ultrasonic cleaning followed by a hot acid pickle to remove active rust, as necessitated by prolonged sweat or saltwater immersion, or alternately hand carding off any internal rust, then replacing and fitting either a new cylinder, or barrel or critical internal parts and rebluing, the bill can easily run $500-600 if done professionally by a Pistolsmith Guild smith of national reputation.

Some things have probably changed in DA revolver manufacture since my time. The big thing is that in making guns only for the civilian mass CCW market the pressure is on production and profits, not quality. I'd spend more money for an old gun that works than for a new one which doesn't.

Back when I inspected guns for use by the Federal agencies in the 1980s the above describes how it was done. Some things are not discussed, such as comparing the color of the burn stains on the cylinder of a new stainless revolver, and looking for red or purple dye on the recoil shield to be sure it got six proof rounds, and that some bean counter wasn't saving a buck by shooting only 1 proof load and 5 regular service rounds.

Customs and Border Patrol back in the 80s rejected a lot of revolvers when an inspector noted that some cylinders had one deep black burn stain and five brown ones. Questioned guns were sent to the ATF bomb lab for electron microprobe analysis of the powder residues, which confirmed that the contractor was cheating on proof in violation of the contract requirements for six proof rounds. Those guns were returned to the factory for re-proofing in the presence of the government's Contracting Officers Technical Representative who flew up from FLETC. Out of 1200 rounds fired in retesting there were 34 misfires, or 2.8% which is no good. The misfired rounds were gathered up and sent to Picatinny Arsenal for analysis and it was determined that the firing pin indents were off center more than 1/2 the diameter of the striker point. These are the sort of things that can happen when people aren't paying attention, which you will never read about in news stand gun rags. You have to have “been there.”

I have not discussed here the proper use of a "range rod" or correction of "thread choke" here, because most hobby shooters won't have the tools r skill to properly assess and repair what they find and it is possible to damage the gun if you don't use them properly.

The barrel forcing cone compensates for slight misalignment of the chambers and bore, but if bore-chamber alignment is WAY off, the gun can shave lead, especially from wadcutter bullets, which is annoying for the fellow standing next to you! If you don’t have a “range rod,” an easy "spitting" test you can conduct yourself is to load the gun with .38 Special wadcutters, stick it inside a paper bag, or cardboard box and trigger off a cylinder full DA and then check the bag or box for holes or lead particles sticking in it!

SO there you go, you now probably know more about revolvers than the guy behind the counter at your local gun shop.

You can now assess when he is trying to sell you manure or not. Now carry on!