Revolver checkout: how to tell if a particular specimen is any good

[Jim March]

This thread covers how to pick out a new or used revolver at the gun shop/gun show table without firing it, safely. While I started it and provided a lot of the instructions, others helped fine-tune it and there is other good info throughout the thread:

http://www.thefiringline.com/forums/showthread.php?s=&threadid=57816

This thread may have been the most useful ever posted on the TFL revolver forum, and I'm very pleased to have started it.

Now it won't die.








The text from Handloads.com
Revolver checkout: how to tell if a particular specimen is any good
By Jim March

So you're buying a revolver. New, used, doesn't matter, you want a good one, right? How do check one over without firing it, right at the dealer's counter or gun show table? This is how. All of this works with DA or SA wheelguns..."close the action" on most DAs means swing the cylinder in, on SA types, close the loading gate, on break opens, close 'em. UNLOADED.

WARNING: most of these tests require violation of the "finger off trigger" rule. Therefore, be extremely careful about safe muzzle direction and making sure the gun is unloaded ahead of time, PERSONALLY, as you begin handling it.

Note: bring a small flashlight, something small and concentrated. A Photon or similar high-powered LED light is perfect. You also want feeler gauges if you're not used to eyeballing cylinder gaps; at a minimum, bring a .002", .004" and .006".

Note 2: no dry firing is required or desired at any point. It just pisses off the gun's current owner.

Cylinder play

1) With the gun UNLOADED (check for yourself!), close the action.

2) Thumb the hammer back, and while pulling the trigger, gently lower the hammer all the way down while keeping the trigger back - and KEEP holding the trigger once the hammer is down. (You've now put the gun in "full lockup" - keep it there for this and most other tests.)

3) With the trigger still back all the way, check for cylinder wiggle. Front/back is particularly undesirable; a bit of side to side is OK but it's a bad thing if you can wiggle it one way, let go, and then spin it the other way a fraction of an inch and it stays there too. At the very least, it should "want" to stop in just one place (later, we'll see if that place is any good). The ultimate is a "welded to the frame" feeling.

Cylinder gap

4) Still holding the trigger at full lockup, look sideways through the barrel/cylinder gap. If you can get a credit card in there, that ain't good...velocity drops rapidly as the gap increases. Too tight isn't good either, because burnt powder crud will "fill the gap" and start making the cylinder spin funky. My personal .38 snubbie is set at .002, usually considered the minimum...after about 40 shots at the range, I have to give the front of the cylinder a quick wipe so it spins free again. I consider that a reasonable tradeoff for the increased velocity because in a real fight, I ain't gonna crank 40 rounds out of a 5-shot snub.

If you're eyeballing it, you'll have to hold it up sideways against an overhead light source.

SAFETY WARNING: This step in particular is where you MUST watch your muzzle direction. Look, part of what's happening here is that you're convincing the seller you know your poop . It helps the haggling process. If you do anything unsafe, that impression comes completely unglued.

Timing

5) You really, REALLY want an unloaded gun for this one. This is where the light comes in. With the gun STILL held in full lockup, trigger back after lowering the hammer by thumb, you want to shine a light right into the area at the rear of the cylinder near the firing pin. You then look down the barrel . You're looking to make sure the cylinder bore lines up with the barrel. Check every cylinder - that means putting the gun in full lockup for each cylinder before lighting it up.

You're looking for the cylinder and barrel holes to line up perfectly, it's easy to eyeball if there's even a faint light source at the very rear of both bores. And with no rounds present, it's generally easy to get some light in past where the rims would be.

Bore

(We're finally done with that "full lockup" crap, so rest your trigger finger. )
6) Swing the cylinder open, or with most SAs pull the cylinder. Use the small flashlight to scope the bore out. This part's easy - you want to avoid pitting, worn-out rifling, bulges of any sort. You want more light on the subject than just what creeps in from the rear of the cylinder on the timing check.

You also want to check each cylinder bore, in this case with the light coming in from the FRONT of each hole, you looking in from the back where the primers would be. You're looking for wear at the "restrictions" at the front of each cylinder bore. That's the "forcing cone" area and it can wear rapidly with some Magnum loads. (Special thanks to Salvo below for this bit!)

Trigger

7) To test a trigger without dry-firing it, use a plastic pen in front of the hammer to "catch" it with the off hand, especially if it's a "firing pin on the hammer" type. Or see if the seller has any snap-caps, that's the best solution. Flat-faced hammers as found in transfer-bar guns (Ruger, etc) can be caught with the off-hand without too much pain .

SA triggers (or of course a DA with the hammer cocked) should feel "like a glass rod breaking". A tiny amount of take-up slack is tolerable, and is common on anything with a transfer bar or hammer block safety.

DA triggers are subjective. Some people like a dead-smooth feel from beginning of stroke to the end, with no "warning" that it's about to fire. Others (myself included) actually prefer a slight "hitch" right at the end, so we know when it's about to go. With that sort of trigger, you can actually "hold it" right at the "about to fire" point and do a short light stroke from there that rivals an SA shot for accuracy. Takes a lot of practice though. Either way, you don't want "grinding" through the length of the stroke, and the final stack-up at the end (if any) shouldn't be overly pronounced.

Detecting Bad Gunsmithing:
8) OK, so it's got a rock-solid cylinder, a .002" or .003" gap, and the trigger feels great. Odds are vastly in favor of it being tuned after leaving the factory.

So was the gunsmith any good?

Look at the screws. Ideally, they should be untouched, meaning that the gun has not been messed with. If the screw heads are battered and worn, it means the sideplate has been off, probably many times. A gun like that may have a smooth trigger, but the parts may have been polished out of time or (if a S&W) the case hardening cut through so the parts will wear out rapidly. Many guns subjected to amateur gunsmithing turn up on the used gun market when the guy realizes he has messed up.

Next, cock it, then grab the hammer and "wiggle it around" a bit. Not too hard, don't bang on it, but give it a bit of up/down, left/right and circular action with finger off trigger and WATCH your muzzle direction.

You don't want that hammer slipping off an overly polished sear. You REALLY don't want that . It can be fixed by installing factory parts but that'll take modest money (more for installation than hardware costs) and it'll be big time unsafe until you do.

The other thing that commonly goes wrong is somebody will trim the spring, especially coil springs. You can spot that if you pull the grip panels, see if the spring was trimmed with wire cutters. If they get too wild with it, you'll get ignition failures on harder primers. But the good news is, replacement factory or Wolf springs are cheap both to buy and have installed.

There's also the legal problems Ayoob frequently describes regarding light triggers. If that's a concern, you can either swap back to stock springs, or since you bought it used there's no way to prove you knew it was modified at all .

In perspective:
Timing (test #5) is very critical...if that's off, the gun may not even be safe to test-fire. And naturally, a crappy barrel means a relatively pricey fix.

Cylinder gap is particularly critical on short-barreled and/or marginal caliber guns. If you need every possible ounce of energy, a tight gap helps. Some factory gaps will run as high as .006"; Taurus considers .007" "still in spec" (sigh). You'll be hard-pressed to find any new pieces under .004" - probably because the makers realize some people don't clean 'em often (or very well) and might complain about the cylinder binding up if they sell 'em at .002".

The guns in a dealer's "used pile" are often of unknown origin, from estate sales or whatever. Dealers don't have time to check every piece, and often don't know their history. These tests, especially cylinder gap and play, can spot a gun that's been sent off for professional tuning...like my snubbie, the best $180 I ever spent .

As long as the gun is otherwise sound (no cracks, etc) a gunsmith can fix any of this. So these tests can help you pick a particularly good new specimen, or find a good used gun, or help haggle the price down on something that'll need a bit of work.
This article was originally a webboard post at http://www.thefiringline.com/forums/showthread.php?s=&threadid=57816 from Jim March and re-published with permission and has had minor changes from the original post based on additional information contributed by others in that discussion thread. You can find Jim online at http://www.ninehundred.com/~equalccw/

 

[Jim March]

Well the first post on that thread is here:

http://www.handloads.com/articles/default.asp?id=19

But there's a lot of extra info and discussion on the whole subject in the TFL thread. If you can get there, the TFL version is best .

 

[HadEmAll]

Regarding the timing check, I believe you should hear the bolt fall into the cylinder slot before the hammer is at full cock on ALL chambers. This is the first thing that's gone out on all S&W revolvers I've owned and 2 of the 3 Colts.

 

[WebHobbit]

Only one thing missing from the checkout:

One should really bring a cast bullet to drop down all the chambers to check to see if they are over-sized.

Over-sized charge holes can result in everything from poor accuracy to key-holing. Not good. And you can't fix it short of replacing the entire cylinder!

If the chambers are correctly sized a cast bullet (not loaded round) of the appropriate size will NOT fall free of the charge holes when dropped in.

Example: for .357/.38 a .358 cast bullet should be used. For .45 a .452 cast bullet is fine.

 

[Jim March]

Ah. You know, that's a good point. I wonder if Oleg would be willing to do a series of pics?

In the case of cylinder play, you really have to compare a few pieces and get a feel for what's any good.

On the timing check, I've got a bad feeling I know what's going on: that old S&W is "pinned and recessed", right? Means there's a pin across the top of the base of the barrel (through the frame, horizontally) and the cartridge rims are recessed into cutouts at the back of the cylinder? Methinks the "recessed" part won't allow enough light to shine in back there! Hmmmm...you might have to go to the alternate method: use a thin brass rod down the barrel from the "business end", and "feeling" for the alignment. You're making sure that the "lip" from the junction of cylinder and barrel are the same on each side. It's not quite as accurate as eyeballing it.

You might also try shining a light in down the bore, and "peeking over the top of the flashlight barrel".

Or, if the gap at the rear end of the cylinder is so tight, with almost no light allowed in, you might have to go to a stronger light - a surefire or something .

Once you've got any light down there at all, then it's easy: you're looking for one circle (cylinder bore) lined up with another circle (barrel bore).

-------------

As to the tight spots at the forward end of the cylinder: good news there - if that's beat to hell, or especially cracked/chipped/uneven, it'll be dead obvious .

 

[Jim March]

Nope. The basics of the checkout will work with more or less every revolver going back to the original Colt Patterson of 1836 .

Now, there might be some things that you have to watch on some gun types. A Colt with the Python or D-frame type lockworks should lock up VERY tight, preferrably all the way to the "welded to the frame" feel at full lockup. They can go out of time and if you've got one with a "sloppy cylinder" it can indicate trouble coming a LOT faster than Rugers or S&Ws that normally live with a bit of slop (in the spin direction).

 

[Jim March]

No, once the gun is in "full lockup", you do NOT have to pull the hammer back again! At "full lockup" (and only one hand on the gun), you've got the gun in the same mechanical state it's going to be in when it goes "boom", which is the whole point - you then make sure the barrel and cylinder bore are lined up.

You can do that two ways: use your other hand to shine the light into the rear of the cylinder area and hope you get enough in that it can be seen looking down the bore (in other words, use either a very concentrated or very potent light) OR if that won't work (such as a long-barreled 22 or 17 caliber), use the "rod method" - stick an aluminum or brass cleaning rod down the barrel and into the cylinder, and then on the way out gently "scrape" the interface between cylinder and barrel with the tip of the rod and make sure the "drop" is the same on both sides, by feel. This is surprisingly accurate - if the two sides are off any significant distance from each other, you'll catch it. Not quite as accurate as the light method though.

If it's an old recessed-chamber S&W magnum or some of the 22s with recessed chambers, you're not going to have a lot of room for light to get into the rear of the cylinder area. Ditto a Freedom Arms. A Surefire or other "megalight" may be necessary for that technique. It's worth the effort, as the light will be the most accurate way of doing the "circle in circle alignment" of cylinder bore/barrel.

 

[boots]

please explain

3) With the trigger still back all the way, check for cylinder wiggle. Front/back is particularly undesirable; a bit of side to side is OK but it's a bad thing if you can wiggle it one way, let go, and then spin it the other way a fraction of an inch and it stays there too. At the very least, it should "want" to stop in just one place (later, we'll see if that place is any good). The ultimate is a "welded to the frame" feeling.


i ask, because i have a full underlug gp100(new when i got it) that has only seen about 100(rounds) 38spl, and 100(rounds) 357 mag. it is relatively new, and cosmetically, it is perfect. one thing about this gun was the horrible trigger pull. the solution? dry fire away, you won't hurt your ruger gp100. built like a tank... however, after about approximately 200 of the aforementioned rounds, and countless dry fires(without dummy rounds, the manual does not state that they are needed), the trigger pull is slightly better, but the side to side wiggle is pretty bad (approx 1/64 of an inch). endshake is almost none. it shoots good. accurate out to 25 yards(at least). i classify the side to side movemnt as bad ,not arbitrariliy, but based on comparisons with my half lug 3" gp100. the endshake and side movement is non existant on my half lug. the half lug also shoots great. what i want to know is, how bad is it really to dry fire, even when the manual states that it will not harm the gun. because it seems that the dry firing has caused this side to side movement. actually, the side to side movement is less than 1/64 of an inch.


please, someone tell me to relax, and if it breaks, ruger has great customer service, and 99% chance that the side to side movement is inconsequential and only seems bad because i am extra critical with my pieces, and i should quit being so neurotic about my guns. please help.

 

[Jim March]

Hmmm. Well we have more info to work on now. Good.

'Kay, I'm kinda guessing here, but what I *think* happened was, the dry-firing didn't "damage it" so much as "deburred it" in one or two key places.

On the cylinder are six little "key holes" we'll call 'em. In the frame, poking up from underneath, is the "locking lug", a protruding piece of metal that's designed to fit into those "key holes". Swing the cylinder out and you'll see it clearly.

When the gun is at "full lockup", with most DA designs that protruding piece is "jammed up into a key hole tight", locking the cylinder in place for firing.

I suspect that either the key holes or the protruding bit, or both, had minor burrs that were effectively tightening the action. Once polished away with use, it loosened up a bit.

If so, the loosening will STOP at around where it is now. It bears watching, but if it's stays where it's at and the gun shoots fine, no problem. The Ruger DAs are meant to have slightly loose cylinders, they align themselves at the moment of firing.

What to do: check the timing. Use the "light at the rear" method, and if all six cylinder bores are lining up well with the barrel it is *definately* safe to shoot and if it's grouping OK, congrats: you have a normal GP100.

If this is a 6" barrel, the "light at the rear" method works, but you need a LOT of light or something super-concentrated. A Surefire or similar is perfect; also, some people get good results with a standard Mini-Maglight brand two-AA light with the cap completely unscrewed - the bulb is a teensy skinny little thing that can be crammed almost all the way back into the firing pin area...not quite, but close enough to throw a lot of light on the subject.

What you're looking for is that "circle in circle" thing, where one circle is the barrel (you'll see the rifling, can't miss it) and the other is the cylinder bore. If the latter is off to one side of the barrel bore but still within it, you're OK, but when there's part of the cylinder bore circle unseen behind the barrel bore edge, that's not good. Like so:

In contrast, the classic Colt DA mechanism as found in the Python and others puts a LOT of pressure on the cylinder upwards through that protrusion (at full lockup). This freezes the cylinder "dead in it's tracks". When the alignment is PERFECT, accuracy is great...but the GP100 will keep it's current level of accuracy (which ain't bad) through at least 4 times the shooting volume of a Python and probably more, while the Python needs frequent re-timing by a master Coltsmith.

In other words, if you're headed into the woods or mean streets, and you need to count on the gun, and can make do with 1.5" to 2" groups at 25yds versus 1" at 50 yards for some Pythons, the Ruger is the way to go.

Now, if the slop factor keeps growing, something's wrong. Maybe a bad heat treat on one of the parts such as the locking lug, and it's slowly wearing away. Dunno. Keep your eye on it for a while, re-check the timing once in a while, see if she settles down to an acceptable state.

Hope this helps.

 

[Jim March]

Full lockup on the timing test.

Here's the deal: not all DA designs will require full lockup to do a check. Most will, I think. But most of all, having the gun in the full lockup state will NEVER harm the accuracy of the test, and might help.

You follow me? I'm not 100% certain the Ruger GP100 needs to be at full lockup to check timing and cylinder play. I *think* so. My Charter Arms Undercover does, and that's a distantly related design (the Charter was designed by a former Ruger engineer).

It's not hard to hold a wheelgun at full lockup with one hand while looking down the barrel and shining a light at the rear of the cylinder with the other. Your gun's cylinder may or may not experience a tightening of the cylinder in full lockup versus not. It'll depend on the gun.

To be honest, I only learned that some DAs don't tighten the cylinder at full lockup recently, more recently than the start of the thread back on THR. I haven't made a correction on the subject, because the same instructions still work either way .

 

[Jim March]

The cylinder bore restrictions are a royal pain to measure. The proper diameter varies by caliber of course. Basically, inside-diameter calipers are notorious for taking poor readings of these...to do it right, you have to cram a lead ball through and measure the ball with a micrometer. Wayy too much pain for what we're talking about.

With most guns, if it LOOKS nice and round and clean (no fraying/chipping/corrosion), it's probably OK. There ARE exceptions: the 45LC caliber in particular has had it's specs vary some in the years since 1873, and different vendors are doing different "eras" . S&W is notorious for getting these oversize now and again on N-Frame 45LCs while Rugers tends to be undersize, esp. on SAs. There are two different companies which will ream out your 45LC Ruger Blackhawk/Vaquero cylinder to the proper specs for cheap ($25 - $50) - you send the cylinder by itself.

But outside of the 45LC, this sort of thing isn't common. Most makers get the cylinder throat right - then the issue is wear, and that can be visibly checked for.

 

[Jim March]

We agree on the "wrist snap close" on a standard DA - warps the crane to hell and gone.

But I've handled a LOT of good revolvers with zero detectable endshake, and own one currently. Endshake is NOT needed to prevent rounds scraping on the recoil shield. There should be as little endshake as possible, preferrably none (esp. at the "full lockup point" with trigger held back).

Endshake causes the cylinder to act as a battering ram in both directions on the slightly softer frame metal. You don't want any. A well-made modern gun can survive a small amount of endshake for a long time, but once it gets bad (esp. past .002") it'll get worse all too quickly with hot loads.

As to gap: depending on the powder used, .002" can be just fine. It works great on 38snubbies; most 38 powder seems to burn fine enough to prevent problems until at least 40 or 50 rounds are fired, at which point you have to do a quick wipe on the cylinder face and rear of the barrel with a rag. This very minor inconvenience is worth it for the velocity boost a small gap gives you. This may not be the case with heavier calibers and slower-burn powder, where .003" or .004" may be optimum.

The gap can be increased via a gentle touch with a knife-sharpening stone on the back of the barrel. If test-firing shows a tight gap is "gunking up" on the powder crud from your loads, don't send it back - tune it to what you need. The factory might set to "spec" which can be as high as .009" .

 

[Jim March]

Yes, you're right, that "cylinder throat" is tapering to a constriction.

And yes, this check is a good idea, except make sure it's a BULLET (projectile alone) and not loaded ammo. And show the gun dealer the slug in your open palm and show him how gently you're doing this.

The absolute fastest way to panic a gun dealer is to make him think you're about to LOAD the store's gun you're looking at. If he thinks that's what's up, he WILL draw down on you. Immediately. And he may pull the trigger.

"Mr. Dealer, I'm going to gently check the cylinder throat diameters with this jacketed slug sitting on my open palm right here..."

Do this without warning him, and if all he sees is the tip of your slug in your fingers, he may think it's a loaded round.

OK?

(Jacketed is best, hardcast lead OK if that's all you have. Soft lead will deform too easily.)

 

[Jim March]

Topstrap erosion is definately worth talking about.

It ruins the value of a collector gun, period.

On a "shooter", a little bit can be tolerable. It's not uncommon for the process to start, and in the process flame-harden the metal and then it stops before it's a "structural issue".

So, a little can sometimes be tolerated if the gun is otherwise sound.

It's usually linked to a large cylinder-to-barrel gap though...which isn't good either. It can be caused by running lightweight bullets at crazy speeds with fast-burn powder in a Magnum of some sort. Ruger's 357Maximum was recalled, which in my opinion wasn't right: as long as you use 158 or heavier slugs it was fine, but too many idiots went "hey, we can run 125JHPs at 2,000+!!!" and really screwed the guns up.

Personally, if the erosion equalled more than 5% of the total cross-section area of the topstrap, I'd be very concerned. At 10% I'll flat-out say "don't buy" and many would put that "don't buy" level lower. Depends on the gun though.

 

[Old Fuff]

Go to www.e-gunparts.com

They have exploded view drawing of many different guns, including popular revolvers. The parts are numbered in the drawing, and them matched to a parts list.

"Yoke" (S&W-speak) and "crane" (Colt-talk) are the same part by different names. Both are the hinge-part that holds the cylinder at the front when you swing it out for loading or unloading.

 

[Old Fuff]

You have to do some of the tests with the revolver in "full lock-up." This is more important with Colt's them Smith & Wesson's, but Jim was trying to cover all of the different makes.

You can cock the hammer, hold the trigger fully rearward (which releases the hammer) and then fully lower the hammer with your thumb so that it is all of the way down in the firing position. Then while holding the trigger back perform each of the tests requiring the revolver to be at "full lock-up."

Of if it would be any easier, cock the hammer, hold back the trigger, lower the hammer (as described above) and then do one test and when finished, release the trigger and let it go forward. When you are ready to do the next "full lock-up" test, again cock the hammer and repeat the process I described in the second paragraph in this post. Repeat this procedure as you do each test.

Those tests that require the gun to be in "full lock-up" are noted in the text. In tests where this is not specified you can let the trigger be forward because "full lock-up" is not required.

Mainly, the tests that require "full lock-up" do so because you are testing how much play (rotational and back & forth) the cylinder has when it fires a cartridge; or how well the chambers line up with the barrel. Usually gunsmiths use a tool, called a "range rod" to check chamber/barrel alignment, but since very few gun buyers have such a tool, Jim has proposed a system where you backlight the chamber with a flashlight and then look down the bore for a shadow thatwould indicate a misalignment.

Other tests determine if the cylinder is rotating like it should, and if it locks-up when it's supposed to.

Once you have practiced all of this it becomes very easy, but the first time around just take your time, and do each test individually. There is no reason for you to be in a hurry.

 

[Old Fuff]

Within reason, Smith & Wesson's service department will do anything you ask, so long as you pay for it. What they might not do is set back the barrel as a warrantee repair, but one never knows.

I don't believe they use bearings, because they have tooling to stretch the yoke's barrel (the part the cylinder revolves on) but whichever the method, what they do will come out right.

One full turn of the barrel = about .028"

They would correct the end-shake, and then set back the barrel. Having done that they would trim the back of the barrel to get the gap you wanted, and then recut the forcing cone.

I believe their production specifications call for a gap around .006, +/- .003" which they try to hold toward the tight end. Back when lead bullets were more common the gaps were generally larger. However within the service department tolerances on a particular gun can be held pretty tight, however too tight may leave you with a cylinder that won't turn if the cylinder face and barrel get fouled. I wouldn't go under .003", and .004” is better, and I expect they won't either. If you do go for a very tight gap plan on shooting jacketed bullets exclusively, and tell S&W that this is your intent.

Incidentally, when they get the gun (if they do) it will go through a complete inspection. Then they will contact you with their recommendations, which may include some things you weren’t aware of. Then they will proceed with the work after you give the O.K., but not before.

 

[Jim March]

Monkeyleg: I haven't been watching this thread as much as I should have.

I think I did get the terminology wrong on the cylinder alignment test. After all the input and time gone by, we should probably do a re-write.

That said, I do believe that visually checking the barrel/cylinder alignment at the moment the gun would otherwise go "bang" is useful regardless of what it's called. It gives you a good idea what will happen at that point. I don't think range rods or the like are normally needed except on very long barrels or very small bores - at least 90% of what we're dealing with and 100% of the reasonable defensive guns can be covered with the flashlight-and-eyeball trick.

If nothing else, this thread (across both forums) has gotten people thinking about the idea of visually inspecting revolvers in a systematic fashion. The guns I've used it on have proven themselves exceptional shooters that I will never willingly part with.

Will this process find all possible problems? Heck no. It raises your odds of getting a good gun.

I think terminology matters less than that.

I'm going to be busy as hell for about...two weeks or so, then I'll settle down and submit a rewrite as a document attachment for commentary/editing.

If somebody else wants to make such a start, cool by me . Drop me EMail so I'll see it right away. I can do a fast translation from MS-Word to OpenOffice so every possible reader can see it if needed.

[email protected]

 

[zinj]

I think the first post really needs to have a check for "carrying up" added; as it is currently written this important test isn't obvious to a neophyte. To check for "carry up" one needs to cock the hammer as slowly as reasonably possible and listen to the cylinder stop falling into the notch cut into the cylinder. If it doesn't click before full cock the gun is not carrying up and will need some gunsmithing (and not the kitchen table kind). On DA revolvers the shooter should ideally also try pulling the trigger as slowly as possible (not the easiest task) and determine that cylinder clicks into lock before the hammer is dropped. Note that this test must be performed on ALL cylinders!

For those not in the know, a revolver in proper working order locks the cylinder into alignment before the hammer falls, otherwise you get nasty effects like lead spitting. This is called "carrying up." The revolver's spinning action is accomplished by the action on a piece of metal often called a "hand" upon a series of notches cut in the back of the cylinder (usually on the ejector star on DAs). Failures to carry up are caused by wear on either the hand or notches that reduce the range of motion produced by the cocking action. As said before, this causes the hammer to drop before the cylinder is locked, essentially causing a form of "out of battery" fire.

The most important part of this test is that the gun must be cocked VERY SLOWLY. If the gun is cocked at even a moderate speed the inertia of the spinning cylinder will continue to carry it into battery even though the hand has not travelled far enough to push it into lockup on its own. Some people dismiss the importance of this, but this is condition that gets progressively worse with more shooting. It WILL eventually need to be fixed, so it is better to catch it early and know what you are getting into.

EDIT: I see that someone else brought this up, but it was buried on page 5 of this thread. I really do think this information needs to be in the first post, not 80+ posts in.