29-3 intermittent cylinder advancement failure

[flyfishinjunkee]

Occasionally when shooting my long tube model 29-3, the cylinder does not engage or rotate to the next cartridge when cocked. This gun has been shot alot in the past. I suspect a problem with the hand and I have had several s&w revolvers disassembled down to a bare frame.

How do I go about diagnosing this problem? Where do I get parts? Thanks

 

[armorer951]

I guess I would start with a complete cleaning and check of the specs on the cylinder assembly. Shooting debris in the hand window can cause intermittent problems.
The other issue may be excessive end shake, which can move the cylinder forward to the point where the hand may not be able to contact the ratchet. Could also be a combination of things.

Many other possibilities, but I would start with a thorough disassembly and cleaning..... and checking parts and specs.

 

[flyfishinjunkee]

what are the specs on the cyl assembly and how are they checked? thanks

 

[Alk8944]

A thorough cleaning is where to start, paying particular attention to the ratchet, trigger and hand slot in the frame.


With this revolver have you taken the trigger out of the gun? If you did, did you remove the hand from the trigger?

Does the cylinder rotate if you hold the gun muzzle down, but doesn't dependably in other positions? (Note:It may not work when held muzzle down if there is anything causing drag on the hand, like fouling of any sort, grease, oil, etc.) Open the cylinder and cock the gun. While holding muzzle down does the hand protrude from the breech face, and if you push it into the frame does it fall back out on its own? It should!

If it works muzzle down the hand was installed in the trigger without the hand spring properly positioned to put pressure on the pin on the hand that the spring is supposed to bear on! This is common when inexperienced persons completely dis-assemble and then attempt to re-assemble the revolver.

You have to raise the tail of the hand spring with a punch from below the trigger as it sits in the gun. The trigger must be out of the gun to do this. Raise the spring tail to where it is above the slot for the pin on the hand, then install the hand in the trigger. This takes the proverbial three hands (yours), or a vise to hold the trigger while you fuss with the spring, punch and hand.

If your hand has two pins it is the one farthest forward which the spring bears on. If three pins it is the middle one.

 

[armorer951]

The rear gauge or "headspace" between the rear of the cylinder face and the breechface can be checked with feeler gauges after cleaning and wipe down. Correct rear gauge on your model would be .060" - .068".

 

[armorer951]

These photos of my old de-milled 686 illustrate the movement of the hand throat as the trigger is pulled, or the hammer is cocked back.

Shooting debris, damage to the hand slot, hand, or the hand being out of alignment can cause it to malfunction, and not reach out to it's intended interface with the ratchet. If the hand spring is broken, or not installed properly, as Alk8944 previously indicated, the hand will not move forward as required.


Hand at rest, flush with the extractor cutaway:




Trigger/hammer pull begins, hand throat moves out of the hand slot (under hand spring tension) as it begins it's upward travel:




Hand moves upward as the cocking motion of the action continues:





Hand almost fully upward and fully extended:

 

[shawn mccarver]

Simple check: Has the arm of the coil spring become disengaged from the stud which puts forward spring tension on the hand?

You can check for this by making certain the hand is under spring tension holding it forward.

It is relatively easy to pull the hand back too far when removing or reinstalling the trigger thereby causing the arm of the coil spring to become disengaged from the stud which results in no forward spring tension on the hand.

 

[DeplorabusUnum]

I had the same/similar problem with my model 27. The spring arm that keeps tension on the hand had somehow become detached from the hand. A simple test is to hold the gun with the barrel pointed up and pull back the hammer. Even if the spring is not connected properly, it will still rotate the cylinder. Then try pulling back the hammer with the gun level pointed forward. Without the spring attached correctly, this will not rotate the cylinder. If this is what your gun is doing, simply re-attaching the spring arm to the hand may be all you need to do.

 

[flyfishinjunkee]

Wow, some great advice. I'll pull this thing out today and try some of the suggestions. THANKS

 

[USBP SW]

You might also check to make sure that the cylinder stop isn't becoming disengaged during recoil and partially advancing or retarding the cylinder. If it doesn't happen when cycling the revolver while empty, it's something likely caused by recoil.

 

[Alk8944]

Wow, some great advice. I'll pull this thing out today and try some of the suggestions. THANKS

Just a simplified revision of my first post. Open the cylinder of the gun then pull the thumb-piece to the rear to allow the. hammer to be cocked. Then look to see if the hand protrudes through the breech face. If it does simply push on the hand with your finger, does it spring back when you release pressure? If it does then the hand spring isn't the problem. If it does not then the hand spring is the problem and refer back to my first post for how to fix it!

This was the long way of saying just push on the hand to see if it is under spring tension without having to dis-assemble the gun to check it.

 

[243winxb]

29-2 intermittent cylinder advancement failure

Newer models have an "Endurance Package" for this problem. I sent my 29-2 back to S&W because on firing, the cylinder rotated back. The next shot would hit the already fired case. Cylinder unlocked? New springs helped some.

The main problem for me is the blow back from cast bullets gets in where the hand rides. The area need to be flushed out with a spray cleaner after every shooting session.

Factory replaced these parts/photo & 8 3/8" barrel w/Mag-Na-Port was set back.

My guess. Not a gunsmith.

 

[Alk8944]

Tried to send you a PM asking what you had discovered about your problem so I could advise you further if necessary but got the message that your stored messages have exceeded your limit and you need to delete some of them to free up some space!

 

[GBertolet]

I had the problem of the cylinder unlocking during recoil in my 29-2. The torque of the recoil, turned the cylinder slightly clockwise, so recocking the gun, brought up the just fired cylinder. It didn't do it every shot, but it did it often enough. I sent the gun back to S&W. They replaced a bunch of parts, running up a considerable bill, and they didn't fix it anyway.

In my case, a quick and dirty fix, was getting Wolff extra power cylinder stop springs, which seemed to fix my issue. I stay away from the super hot loads nowadays. Be advised, that S&W never intended or expected, their 29's to have high round counts of full power ammo fired in these models. It was designed as a hunter's handgun, expecting seasonable use. After S&W became aware of this issue, the endurance packages were incorporated.

I hope this might help.

 

[DWalt]

I once had the same cylinder counter-rotation problem in my 29-3. It was much worse with heavy loads. I put a heavier cylinder stop spring in, and that eliminated the problem with lighter loads, but not heavier. It is difficult to describe but I came up with home-made remedy made out of a small piece of sheet metal to retain the cylinder stop spring in place and that solved the problem. But still, I generally fire mainly milder handloads, very seldom full house loads. I once called S&W about the problem and they insisted that the problem was my imagination. Thereafter, I refuse to ever call them about anything again.

 

[armorer951]

Caution.....there is zero "engineering" or science that follows, only my opinion. Take it with a grain of salt, as we used to say.

One of the main issues with the cylinder unlocking during recoil in the high power revolvers like the model 29 is the inherent instability caused, in part, by the design of the cylinder stop.

The S&W cylinder stop, by design, moves in four directions on the frame stud when in contact with the trigger....down, up, forward and backward. These motions are accommodated by the space provided in the frame cavity, and the cylinder stop itself, and are caused by the trigger hook as it moves down during the trigger rearward pull, and back up, as the trigger returns and the hook moves up over the stop bevel.

The unlocking problem occurs when the trigger is back and the cylinder stop is in battery, inside the cylinder stop slot in the cylinder. When the revolver fires (under heavy recoil), the frame cams to the left, moves forcibly back, and the cylinder stop "moves forward" on the stop's frame stud. (overcoming the pressure supplied by the stop spring) At this point, and because the ball of the cylinder stop has moved forward (out of) in it's position in the cylinder slot, the cylinder may cam off of the cylinder stop, and out of the stop slot in the cylinder. The result is that the proper timing of the next trigger pull is interrupted, as the cylinder/extractor assembly is not in the correct position to be acted upon by the trigger/hand movement. If the hand picks the cylinder up at all, it is rotated back to the chamber that just fired.

An additional problem is that the actual shape of the stop can contribute to the malfunction. The stop ball is rounded on top to conform to the slot in the cylinder. Guess what, as the stop moves forward under heavy recoil, it literally cams itself down and out of the cylinder slot.
And, if you look closely at the cylinder stop, between the ball of the stop and the adjustment step on the stop body there is a raised/angled area in the neck that can come into contact with the front edge of the stop's frame slot window. The angle here can cause the stop to move down (out of the cylinder slot) during very heavy recoil.

Add in the other possible manufacturing and fitting variances involved, including stop fitting during assembly, where the stop may be left at a point not high enough in the frame to fully engage (bottom out) the cylinder slot, and the instability problem is exacerbated.

Replacing the stop spring with the heavier Wolff spring can help mitigate this issue, along with using "conventional" or factory loadings.





Carter

 

[Alk8944]

Why did everyone suddenly get on the issue of cylinder un-locking under recoil???????????


This is not the issue he was asking about, he has problems with the cylinder not turning reliability when the hammer is cocked! The endurance package has nothing to do with OPs problem and question.


READ the OP before jumping to conclusions and spouting off about something entirely un-related!

 

[DeplorabusUnum]

Why did everyone suddenly get on the issue of cylinder un-locking under recoil???????????


This is not the issue he was asking about, he has problems with the cylinder not turning reliability when the hammer is cocked! The endurance package has nothing to do with OPs problem and question.


READ the OP before jumping to conclusions and spouting off about something entirely un-related!

There was a post mid thread describing this new problem, completely different than the original one described by the OP. Somehow it picked up momentum and took over.

OP, I am interested in hearing whether or not you've solved the problem.

 

[armorer951]

Why did everyone suddenly get on the issue of cylinder un-locking under recoil???????????


This is not the issue he was asking about, he has problems with the cylinder not turning reliability when the hammer is cocked! The endurance package has nothing to do with OPs problem and question.


READ the OP before jumping to conclusions and spouting off about something entirely un-related!

The OP stated "Occasionally when shooting my long tube model 29-3....."


Perhaps those posting, or "spouting off", mentioned this problem because this stated issue is not "unrelated" to the OP's problem, and may in fact be the reason why the cylinder is not advancing?

If the cylinder is unlocking under recoil as proposed, the cylinder/extractor will be moved out of position, and the cylinder will not (may not) advance as usual when the hammer is cocked or the trigger is pulled.

Why can't all the possibilities be considered?


Carter