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Thread: Revolver Inspection - The Right Way - aka Wheelgun 101

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    Boolit Grand Master Outpost75's Avatar
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    Revolver Inspection - The Right Way - aka Wheelgun 101

    Revised 1/30/2018 thanks to useful suggestions from government and trade professionals.

    Based upon the repeated questions from readers here and elsewhere and my having to repost common knowledge, it is apparent that basic knowledge of DA revolver inspection has largely been lost. I've attempted here to post a tutorial of the basics. Not thoroughly comprehensive for professionals "in the trade" but intended as tutorial for the non-professional user, covering the normal aspects of revolver annual inspection as was practiced by police armorers back in the day when your life depended upon your service revolver going "bang~!" every time.

    - Pay attention, Grasshopper and you will know how to inspect a used gun before buying:

    Open the cylinder, with muzzle pointed into the clearing barrel.

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

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

    Confirm proper function of the thumbpiece when releasing the cylinder.

    Inspect the firing pin hole in recoil plate/frame bushing for peening, stone off any burrs.

    Restake or replace recoil plate or firing pin bushing if loose, cracked, damaged.

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

    Visually inspect front end of S&W center pin for peening.

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

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

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

    Close cylinder with thumb and forefinger.

    Cylinder must not strike barrel when closed!

    Confirm positive front and rear S&W or Ruger center pin lockup fore & aft as it is again closed.

    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 frame opening between cylinder and barrel.

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

    Min PASS dimension is 0.003", tighter 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 which protruding out both sides of the frame window between barrel and cylinder binds rotation so that resistance is felt in DA trigger squeeze.

    Max. hold is 0.008" measured with "rear gage" or fired brass in cylinder.

    Customer service max. barrel-cylinder gap is 0.009" if end play is not excessive.

    At 0.010" barrel-cylinder gap the usual procedure is to either fit a new "long" cylinder or 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 cylinder bushing on Colt.

    Feel cylinder fore & aft for longitudinal movement.

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

    Least movement you can “feel” is about 0.002”, if an S&W or Ruger and the cylinder "feels solid" with empty brass in the chambers gun is OK.

    Colt max. end play is 0.003, so if there is ANY felt end shake gun is probably 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 shooting heavy loads, such as +P in J-frame guns!

    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.

    However, the carry-up test needs to be done slowly, as a rapid pull can mask a 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 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.

    Correct procedure on S&W is to bend the hand so the top comes closer to the inside of the hand slot, or to replace with a thicker hand (which is sold for just that purpose.) Rotate hand medially toward cylinder centerline to speed up timing. Conversely to delay it. Sometimes the frame window may need to be opened just a 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 S&W .357s typically required returning to factory for new extractor every 1500 rounds of 357 Magnum loads, while Rugers went 10,000 utilizing Remington and Winchester full charge .357 rounds with no repairs or parts replacements 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 in the early 1980s, conducted by a Aberdeen Proving Ground Certified Small Arms Test Director (who I have known for many years) for the US Border Patrol and US Customs where six Ruger Service & Security Sixes digested 60,000 (10,000 ea) of full house 357 Magnum duty ammo (125 gr and 158 gr) without going out of time.

    Always inspect barrel forcing cones of revolvers. Per statement by Smith & Wesson Factory QA Rep, (1983 time frame) at a meeting at the Federal Law Enforcement Training center to US Border Patrol personnel their 357 K frame barrels are likely to crack in this area at about 3000 rounds and will require 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 possibly 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 is not applicable to Colts; on them 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 on 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."

    To check hammer fall, 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%... [B]

    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 willingly 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 3-letter agencies in the 1980s the above diatribe 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. The 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. Things that can happen when people aren't paying attention.

    Nor did I discuss proper use of a "range rod" and correction of "thread choke" etc., because you won't have the tools to properly assess or fix and you can 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 the 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 and you can now assess when he is full of manure. You don't have to thank me, it has been my pleasure. Now carry on and be safe out there!
    Last edited by Outpost75; 02-01-2018 at 11:46 PM.
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    Boolit Master
    JBinMN's Avatar
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    Very nice write up!

    Thanks for taking the time!
    2nd Amend./U.S. Const. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."

    ~~ WWG1WGA ~~

    For the Fudds > "Those who appease a tiger, do so in the hope that the tiger will eat them last." -Winston Churchill.

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    Boolit Master



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    Thank you Sir.
    Hate is like drinking poison and hoping the other man dies.

    *Cohesiveness* *Leadership* *a common cause***

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    Boolit Grand Master Outpost75's Avatar
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    Quote Originally Posted by JBinMN View Post
    Very nice write up!

    Thanks for taking the time!
    Been meaning to for a long time, but after a couple recent discussions with Sandy Garrett at NoVa Gun Works, Grant Cunningham, and a retired anonymous engineer from Aberdeen Proving Ground who was the government's Quality Assurance Representative I worked with when I was at Ruger and the company was producing revolvers for the US Customs and Border Patrol, I decided it was time to write it up before I started losing brain cells.
    The ENEMY is listening.
    HE wants to know what YOU know.
    Keep it to yourself.

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    Boolit Buddy

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    Thank you, sir.

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    Boolit Buddy
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    Thank you very much, saved a local copy.

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    Boolit Buddy
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    Thank you.

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    Boolit Master
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    THANK YOU

    This should be a sticky

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    Boolit Buddy
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    That's why I love this bunch learn something new everyday !!!

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    Boolit Buddy
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    That's why I love this bunch learn something new everyday !!!

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    Boolit Master GhostHawk's Avatar
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    Thank You!

    Give that man a gold star!

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    Sticky!
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    Sirach 2: 4-9

    Any questions.......http://http://castboolits.gunloads.com/showthread.php?293211-Bubba-w-a-45-70-is-a-bonafied-straight-shooter
    Or here....http://castboolits.gunloads.com/show...t-shooter-too!

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    Boolit Buddy
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    Thank you. All of your revolver accuracy and maintenance posts are invaluable
    Kirk

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    Boolit Master
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    Thank you for the write up. Always learn from you and others on here.I was always wonder on these guns what to look for and watch for.
    Life Member of NRA,NTA,DAV ,ITA. Also member of FTA,CBA

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    Boolit Grand Master Texas by God's Avatar
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    That is a great tutorial. All I would add is don't forget your reading glasses!
    I wish there were a lot more revolvers on the market locally to inspect.....

    Sent from my SAMSUNG-SM-G930A using Tapatalk

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    Boolit Buddy



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    Quote Originally Posted by Bubba w/a 45/70 View Post
    Sticky!
    I concur ! Please consider making this a sticky...

    rick

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    Boolit Grand Master Outpost75's Avatar
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    Another interesting tidbit, on new stainless revolvers look at the burn stain on the front of the cylinder to ensure that the smoke and burn pattern is the same on all six chambers. If one looks different from the others, it could be an indication that not all six chambers were proofed, but that only one was, and the other five got regular service rounds. A cost saving measure by some bean counter...

    During the 1980s Customs and Border Patrol got suspicious of a batch of revolvers. They had the ATF bomb lab run electron microprobe analysis, as is used to identify bomb residues, on the chambers of a batch of revolvers. All six chambers were NOT fired with the same ammo. Therein lies the clue. So 120 guns were returned to the factory for re-proofing which was witnessed by the government's QAR sent up from FLETC. The 120 guns fired six times with proof rounds equals 1200 rounds. Of that batch there were 34 misfires, 2.8%, which was unacceptable. The misfired rounds were gathered up and sent to Picatinny Arsenal for examination and all were found to have off-center indents which were off more than 1/2 the diameter of the striker tip. Cause was isolated to a mis-located hammer pivot on some frames, which missed gaging.

    Those guns were NOT Rugers.
    Last edited by Outpost75; 12-05-2018 at 06:17 PM.
    The ENEMY is listening.
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    Keep it to yourself.

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    Cast Boolits Owner



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    Quote Originally Posted by Bubba w/a 45/70 View Post
    Sticky!
    Request granted Lance!
    "Things always get better once thought, time, and money are applied in the correct amounts at the correct time"
    - No_1 -

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    Boolit Grand Master tazman's Avatar
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    Thanks for making this post a sticky. It deserves it.

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    Boolit Master



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    Quote Originally Posted by Outpost75 View Post

    In FBI, US Customs and Border Patrol experience S&W .357s typically required retiming every 1500 rounds, while Rugers would go 5000+ .357 rounds with no repairs or parts replacements 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. One endurance test I am aware of done at FLETC in the 1980s a Ruger Service Six digested 60,000 .38 Special training rounds without going out of time.
    1,500 rounds is a good day of shooting in a PPC revolver. Great post but needing to retime a Smith every 1,500 rounds doesn't match my experience with them.

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check