Question for you gunsmith types

I just Googled around a bit to see if I could find info on recommended cylinder/barrel gap for .22 pistols, and while I could no specific numbers, the general thinking seems to be that tighter is better. You lose a lot of power through that gap.

What I'm most concerned about however is that you say you can push the cylinder toward the trigger (did you mean hammer?). If so, this condition should be remedied before any other work is done. Any movement of the cylinder should be minimized to insure accuracy and to prevent loss of power/velocity (and possibly safety if it should spit powder or lead out of the gap). I would remove the cylinder and look for where the play is occurring, and then go from there to fix the problem.

If that's the model 999 Sportsman, then I used to have one of those many years ago. While the specimen I had was okay, I've read mixed reviews about their quality. It doesn't seem to have been produced in a magnum version, and given its suspect quality I don't think I'd push it unless you have a way to safely test fire it (in a steel shroud with remote firing set up).

P.S. I'm not a gunsmith, though I did have ambitions of becoming one when I was young.

A well used revolver will develop cylinder gaps that are of the order you mention. The usual recourse is to remove the barrel, and if screwed in, add threads, so that you can close the cylinder gap to .005 -. 010. ( the correct gap size can be determined by a call to the manufacturer or measuring a similar brand new revolver) Sometimes in order to allign the sights correctly at full barrel torque down, the gap will be negative and you will need to cut the portion of the barrel protruding into the cylinder space. Then you also will need to recut the forcing cone. You should check the back strap of the revolver for stretch, cracks and erosion (flame cut) around the gap area.

On the question of the 9 shot top-break ( probably a model 925,926,935 or 999), do not ream the 9 shot cylinder to accept .22Wmag. There is not enough meat for the pressures and you don't know if there are internal cracks or stresses in the original cylinder. You can make a new cylinder out of 4140 and retime it for 6 shots,then harden it to a minimum R35 ( or start with pre-hardened stock). You will also have to manufacture a new extractor. The question is the barrel. It is sized for .22LR and a .22WMag ideally requires a barrel up to .001 larger. Not really a big deal with a revolver, because there is a place for pressures to go (the gap). The frame of these guns is strong enough for .38 special and you could just buy a barrel and cylinder/extractor in .38 special from Numrich.

cheers T.Alan

Greetings Artemia, Yes, the 9 shot pistol is a sportsman. In very good condition. And it is quite accurate. And you are right about the other cylinder. I meant to say hammer, not trigger. The reason for the back and forth play of the cylinder appears to be that it is just too short. It measures .016 shorter than the space it fits into. Wear could have occured on the indexing teeth but I think that's unlikely. Besides, with shells in the cylinder the movement towards the hammer is limited. So it appears that the the thing was made with the large gap between the cykinder and the barrel. ERS

According to Eric R Snow :

I've seen cylinders on some guns with a turned bushing surrounding the locking pin (or one at the front of the cylinder, holding it back against the frame). This controls the rearward motion. Yours may have such a bushing which is now badly worn. It may be possible to machine a replacement bushing, if the existing one is/was a press fit.

Note that if you unscrew the barrel, and face it enough to take up that slop, you will wind up with the front sight off to one side, as the barrel will have to rotate somewhat to screw in far enough to fix your clearance problem. And if it the barrel happens to be octagonal (I don't know your particular weapon), only certain positions can accept a replacing of the front sight.

What I might try, assuming that the barrel has an unthreaded portion projecting into the cylinder hole in the frame, is to turn up a collar which is a slip fit on the rear of the barrel, and then closes in to the OD of the projectile (assuming that the rifling is well enough centered in the barrel -- otherwise, the hole might need to be a bit larger). You could experiment with aluminum to see what affect it has. (Don't let anyone stand to the sides while you do this.) If it works properly, machine some steel to the proper size, and then blue it before or after pressing it onto the rear end of the barrel.

You might want to chamfer the hole, so it will help to guide the bullet into the barrel if the cylinder is slightly out of time. (The barrel probably has such a chamfer.)

Good Luck, DoN.

Greetings DoN, After looking carefully it seems that the large gap has been there since new. With rounds in the cylinder the cylinder could only move back about .005 before the ends of the shells contact the back face. I thought about the sight deal. And the barrel is octagonal. My plan is to machine off the shoulder of the barrel an amount equal to one pitch. Or, if the thread is too fine, two times the pitch. Then machine the end of the barrel to the desired (required?) clearance. Your idea of a bushing might work. But it looks as if it would only be about .050 long and only engage the barrel about .020. I suppose it would work for a test fire though because it would be trapped between the barrel and the cylinder. The back end of the barrel is indeed chamfered. Thanks for the input. Cheers, Eric

I must point out that this chamfer is very important. It is called a "forcing cone" and does indeed guide the projectile into the barrel. I would hesitate to tamper with it too much.

I read your response to my comments, and I'm still concerned about that cylinder. From your description it sounds like the rims of the shells are touching the back of the frame and therefor are taking up the play, forcing the cylinder forward. That sounds potentially very dangerous given that these are rim fire shells. If the pistol were to be dropped in such a way that the front of the cylinder was struck there is a chance that the shells might detonate.

I still think that the main problem is in the play in the cylinder, and that as DoN says, there may be a worn bushing at the back of the cylinder (or it could be a design flaw or other defect from the factory).

I wish Jack Erbes was here! He'd know for sure!

P.S. Have you asked on rec.guns yet?

Do you know specifically what part(s) wear to cause this increased gap? Moving the barrel back to compensate doesn't sound like the best fix if the wear is in the cylinder somewhere.

Thanks, from a curious armchair gunsmith.

I don't know in this particular case. I have seen revolvers where the backstrap/frame had stretched, others with forcing cones that had eroded because the barrel where the cone was cut was to thin to start with. I should have said "some" well used revolvers will develop.... As by far not all of them do if you feed them the correct ammo.

cheers T.Alan

Barrel gap to be .003-.008

Note that this will tend to bind after a number of rounds fired. More if the ammo is "dirty" and less if "clean" If the timing is off..it may bind with less due to spitting, but thats a good start. Id set it at .008 personally.

Id avoid converting the top break to the .22 Magnum. You are gaining very very little in that short barrel. Use Stingers or other high velocity rounds

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Actually, very safe and common practice. It takes far more than a drop to detonate the priming compound in the rims.

Sounds like a worn bushing..however...the weapon in question was built to very loose tolernences Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

I need to be more clear in my posts. On the back end of the cylinder are teeth which are used for indexing. These teeth are flat on top and rotate against a machined surface which limits the movement of the cylinder away from the barrel. With shells in the cylinder there is a .004 gap between the rear of the shell and the back of the opening where the cylinder fits. I think this part is called the frame. Anyway, with the cylinder travel away from the barrel limited by the teeth on the cylinder and if they were severly worn by the shells themselves there is a large gap. If the cylinder is pushed all the way forward this gap is about .002. So, it seems that two fixes are possible. Either build up the teeth on the cylinder and re-machine to the desired length (hard), or remove the barrel and machine the shoulder to the desired clearance (not as hard). If the second option is used the end of the spud which limits forward travel will either have to be built up and re-machined, or a washer will need to be used, or the spud can be removed, the cylinder counterbored, and a new spud machined and pressed into the cylinder. I think that's clear enough. But I often have a hard making myself understood. I'd be a lousy teacher. ERS

The correct way to fix it is the later, set the barrel back. The ratchet tooth height sets the headspace and it sounds about right as it is. Building up the ratchet increases the headspace which is wrong and dangerous in itself plus the firing pin might not reach if you did.

The cylinder end-shake is corrected first by shimming or what ever it takes, then the barrel is removed and machined to allow one additional complete turn on reinstallation. Then the barrel breech end is cut to set an .003"-.005" cylinder gap. The barrel throat chamfer will then most likely need to be recut.

Brownells sells all the tooling for this procedure. For a one-off job, it is likely cheaper to take it to a gunsmith.

Randy

If the gap is within reason with a loaded cylinder..dont bother with it. This particular arm is notable for its loose tolerences. Which is why they last forever.

While at the range, load the cylinder. Pull the hammer to the rearmost postition and hold it. Pull the trigger, while continuing to hold the hammer back, and check the cylinder for looseness..IE see if it will rotate any significant amount. If so, then there are some things that need to be adressed, but if not...dont worry about it.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Greetings Randy, Thanks for the post. It's nice to get info from someone who knows. As for sending it out, well, I own a machine shop. And machining is not just my job, it's also a hobby. So all the mods to this pistol will be easy for me. I just didn't want to do something stupid. Now, another question if you don't mind: My other pistol is an H&R model 999 Sportsman. In case you aren't familiar with this gun it is a .22 caliber, 9 shot, top break revolver. A friend of mine told me about revolver he has that has different cylinders that can be exchanged. One is for .22 LR and the other for .22 magnum. I have looked a little for a similar cylinder for the Sportsman with no luck. If I am able to find another .22 LR cylinder for this pistol would it be safe to alter it for .22 magnum and fire the pistol? I can even make a cylinder from scratch but I don't know how to determine if the pistol can safely fire this round. I suppose I could look up the load a .22 mag puts on the gun firing it and use the strength of mild steel and the way the gun is put together but it makes much more sense to find out from someone who knows if I'm doing it correctly. Or to tell me to get real and don't mess with it. Cheers, Eric R Snow, E T Precision Machine

Do you have a drawing of the cylinder? I know of an H&R 922 that is missng it's cylinder. Randy

According to Eric R Snow :

Are both 9 shot? I strongly suspect that the .22 Magnum would be 6 shot, so the walls between the chambers are thicker. The 9-shot cylinders are really pushing the strength of the cylinder material. (I'm not sure whether there is sufficient travel in the indexing pawl to properly index a six-shot cylinder in that weapon. If not, then perhaps there never was a .22 Magnum version of this weapon. (And I personally tend to dislike the idea of putting any kind of Magnum in a top-break revolver, as the frame strength is much poorer.)

Try looking at old ads for the company back when that was made to see whether the .22 Magnum was considered an option.

With a 9-shot one -- I strongly doubt it. A six-shot might be strong enough, with the right metals.

I would also want a cylinder which shrouds the back of the case for a .22 Magnum, as the chance of blowout at the rim is increased. (Just as you will proably find .38 special cylinders with the base of the cartridge projecting out behind the cylinder, but the magnum version should have the base shrouded.)

The cylinder walls are the first weak point, which is why I don't think that you will find a 9-shot cylinder for the same weapon. (It would need to be a larger diameter to make for thicker inter-chamber walls.)

Next is the strength of the frame, and I don't really trust a to-break frame with more powerful cartridges -- though I could be wrong about the .22 Magnum.

My suggestion would be the latter -- but I don't know from personal experience.

Part of the problem with any rimfire cartridge would be the lack of the ability to make a "blue pill" to stress test it in a safely enclosed test fixture. Until you have passed several such test shots, you really don't know when it may decide to fail -- usually *not* on the first shot, unless it is really severely under-strength.

If you want something which packs a punch in a .22 revolver, look for one of the S&W .22 Jet revolvers. The .22 Jet is a 357 magnum necked down to hold a .22 jacketed bullet. Note that you really want to have the cylinder walls free of oil and dry (and the same for your reloads), or the cartridge will back out and bind the cylinder.

Now *that* weapon was available also with a replacement cylinder for .22 LR. And *that* cylinder, I would expect to be capable of being bored out for .22 Magnum.

Out of curiosity -- since I don't have any .22 Magnums available to check -- is the diameter of the rim larger than on the .22 LR? If so, the firing pin will not strike it in the proper place, and it is very likely to misfire or hang fire frequently. The S&W .22 Jet has two floating firing pins, and a switchable striker in the hammer. And even if you don't have the alternate cylinder, there was a set of sleeves to allow you to fire .22 LR from the same weapon for low-power practice.

This was particularly attractive to those in certain South and Central American countries, where the laws prevented a civilian from having anything larger than .22 -- but the .22 Jet had a very impressive bark. :-)

Enjoy, DoN.

NO,obut I could make one. The 9 shot cylinder for the Sportsman has a feature that pops the spent shells out when the gun is opened. The Trapper model has the 7 round cylinder without any fancy features. Let me know which you need and maybe I can help. ERS

Thanks DoN, you've given me lots to think about. The first thing I need to do is look at my friend's pistol and see how it works. I don't know if it's made by H&R or even if it's a top break. He was just telling me about his when we were shooting some rifles the other day. Eric

A heads up for anyone reading. Somewhere in my Stuff I have a .22lr cylinder for a Ruger Blackhawk

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner