Frustration--Model 34-1 Cylinder Binding

[HAM]

I love this little gun but it must get fixed. After firing a few rounds the cylinder gets harder and harder to rotate. This gun is always well cleaned, crud free and the ejector rod is not bent or loose. I'm using Federal (Walmart) ammo but have used several others as well.

I've come to the conclusion that the problem lies in the fact that the rims are deformed slightly by the firing pin strike resulting in interference between the rims and the recoil shield.

The barrel/cylinder gap with trigger back and hammer down is .003 max. This seems small but I don't know what the proper gap specification is.

The only fix for this irritating problem seems to be to mill a few thousands from the forcing cone to open the B/C gap to say .006.

I hope some experienced hand can set me on the right path here.

Frustrated in Missouri

HAM

 

[semperfi71]

Ham,

I ain't no expert but here is what I have learned.

1. During the shooting session, especially with lead bullets, lead and powder can build up on the face of the cylinder and cause binding due to tight tolerances between cylinder and barrel. It happens a lot with black powder cap and ball revolvers. Rather than mess with the gap I just make sure I brush off the cylinder face after a couple of cylinders of ammo. Even give it a good cleaning if necessary. My .22s are plinkers and not combat weapons and therefore do not have to run 100 rounds without cleaning.

2. Particles of unburnt powder can easily fall between ejector star and cylinder. It doesn't take much to tie up the cylinder. So I always try to make sure that the barrel is up and cylinder rear is down before I eject cases. And I eject them with a sufficient force to have them clear the cylinder clean and rapid.

3. I suspect, with recessed chambers, that .22 caseheads can expand enough to tie up the cases in the weapon and cause difficult ejection. As such the "mass" created by the expanded case heads could possibly also, "overflow", if that makes sense and bind the cylinder rear to the recoil shield. Sort of as does the powder, or anything else that gets underneath the ejector star, to cause binding. But again, this is conjecture on my part.

4. The cases, due to tight chambers, may not be properly seating with each successive cylinder reload because the chambers are getting dirtier with each shot. So the cases are sticking a bit out the back and again binding the cylinder to the recoil shield. It doesn't take much to bind the cylinder.

5. Tight chambers, MIGHT, cause cases to back out a bit on successive firings, this will, once again, cause binding.

Whatever you find out or decide to do, do take the most minimal path and see if that fixes the problem. For instance you mention you think the barrel/cylinder gap may not be enough so you are thinking of having the back of the barrel relieved. I would suggest looking for less permanent fixes before arriving at that one.

Good luck.

 

[RussellD]

just for giggles- clean your gun well and try a box of .22 shorts. Tell us what happens with the shorts. Dont remove any metal yet....Please

 

[cp1969]

If you think the rims are being deformed, decrease the tension on your mainspring and try it again. As long as you get reliable ignition, that screw does not have to be screwed all the way in.

Like Semperfi71 said, watch for crud under the extractor star. I carry an old toothbrush in my range bag just for that purpose.

 

[ms]

The barrel/cylinder gap with trigger back and hammer down is .003 max. This seems small but I don't know what the proper gap specification is.
HAM

What's the gap with the cylinder pushed forward, and with it pulled back?

 

[HAM]

ms,

With hammer down and finger off trigger.

cylinder held back---.004
cylinder pushed forward---.0025

I have obtained a copy of Kuhnhausen's shop manual "The S&W Revolver" but nothing jumps out at me concerning this problem. Will read it carefully tomorrow.

HAM

 

[ms]

ms,

With hammer down and finger off trigger.

cylinder held back---.004
cylinder pushed forward---.0025

I have obtained a copy of Kuhnhausen's shop manual "The S&W Revolver" but nothing jumps out at me concerning this problem. Will read it carefully tomorrow.

HAM

That sounds about perfect. Do you know where the binding occurs? If you open the cylinder after it has been binding, are there scrape marks on the cylinder face?

 

[HAM]

ms,

I have not noticed scrape marks on the front of the cylinder but scrape marks are found in an arc pattern on the recoil shield and I'm sure they were made by the cartridge rims as they rotated when the cylinder turned.

HAM

 

[ms]

It doesn't sound like your gun is out of spec. Have you checked for burrs or rough spots on the recoil shield? I have a nickel 34 that is very tightly fit, and if I don't have the chambers immaculately clean it acts like yours. I thought that I was cleaning them adequately, but didn't really get the revolver running smoothly until I cleaned them with a brass brush chucked in a cordless drill. I ran that in each of the chambers, with CLP, for about 20 seconds. It helped lots. Now I do it for a few seconds each cleaning, and have few problems with binding.

 

[kjack1]

Similar Problem with M48

My M48 had really tight cylinder/barrel clearance (I could barely see daylight!). After experience the same kind of binding, I sent it to the factory. The note with the returned gun was "Cleaned". Pretty expensive transportation for a cleaning.

It seemed to rotate OK during the next range session. I passed the potential problem on to the next owner 9with full disclosure).

 

[mtheo]

My 34 ran like a champ......then I began to have a slowly increasing number of misfires. After taking it to a gunsmith it began binding. The heads of the cartridges were bulged out enough to rub the shield. The gunsmith had added a small thin washer to space the cylinder closer to the firing pin to "fix" the gun. I Then sent it to S&W. The removed the washer and replaced the firing pin.....Problem solved.

I think your problem may just be a dirty gun....just repeating others here...thoroughly clean the gun especially under the star.

 

[ViperR]

If you think the rims are being deformed, decrease the tension on your mainspring and try it again. As long as you get reliable ignition, that screw does not have to be screwed all the way in.

Like Semperfi71 said, watch for crud under the extractor star. I carry an old toothbrush in my range bag just for that purpose.

An old tooth brush is always in my bag, too because after approx 200 rounds, the cyl sticks and cleaning underthe star solves the problem.
BTW, the main spring is coiled and can't be adjusted like the centerfire leaf style.

 

[cp1969]

An old tooth brush is always in my bag, too because after approx 200 rounds, the cyl sticks and cleaning underthe star solves the problem.
BTW, the main spring is coiled and can't be adjusted like the centerfire leaf style.

I thought the OP said it was a K frame?

edit: No, he didn't. My mistake.

 

[mikelain]

I too have the same problems

My 34-1 Has the same problems. It just does not like some ammo. Unburnt powder acumulateds under the extractor and causes problems. Certain ammo extracts very hard. Both of these problems take the fun out of shooting this gun.
I too keep an old toothbrush and shoot more expensive ammo.

 

[semperfi71]

kjack1, it's a shame you sold that M48. A good gunsmith could have fixed your problem easy. Just file a small amount off the back of the barrel to acquire proper barrel/cylinder gap.

K-Frame .22s and .22 magnums are rapidly becoming popular.

 

[HAM]

You may possibly recall the cylinder of my M34-1 would jam up after firing a few rounds. Now I'd like to give thanks for the many good suggestions, to solve this problem, offered me by the gentleman of this forum.

However nothing I tried worked. So, I sent it off to S&W for a little vacation and was eventually telephoned by "Vitto" informing me that he had noticed a tiny raised area of the firing pin assembly and consequently he ground it down and shot a few rounds without incident. Problem solved. I would never have believed this tiny high spot of a .001 or .002 could cause such a problem. I had no confidence that it would work for me but it did. So thanks to all the responders and especially to Vitto. Perhaps this information will help someone with the same problem.

Sorry to say that a new problem has arisen but that will have to wait for another day.

Regards,

HAM

 

[Mike SC Hunter]

Glad you got it fixed. On a related note WW 333's extra hard out of my 63/17 & 18. And thats with keeping a bore brush to clean the charge holes every few cylinders. I don't have that problem with any other brand.