Model 29 unlocking?

[Pocketrocket]

I posted about this before and I think I have identified the problem. I have a 29-2 that has 5-6k heavy loads through it. It has an excellent trigger and no turn line, it had an action job done by Frank Taber in the SF bay area when new. The problem is the cylinder unlocks on recoil. It doesn't swing open, but after firing the cylinder is unlocked between chambers. I took it to a local place but do to poor communication ( i.e. the gunsmith didn't bother to call me as instructed ) it's still not fixed. He replaced the hand assuming it was a carry up problem. I picked it up and fired it, same problem. I put a few cylinders through it to try to figure it out. After firing the cylinder was loose and would rotate. I'm guessing the weight of a full cylinder caused it to rotate backwards and on the subsequent shot the hammer fell on the already fired round. I'm think I need a cylinder stop and maybe a heavy duty spring.

Anyone have any input and possibly a source for the parts?
I checked Numrich but doesn't look like they have them.

 

[Protocall_Design]

This is a known problem. The Endurance Package was engineered to fix it, and they did a good job. The fix was to make longer cylinder stop slots in the cylinder, and put in a sliding cylinder bolt lock to keep it from unlocking under heavy recoil.

The cylinder stop would jump the notch as the gun recoiled backward, and the cylinder bolt would also come unlatched.

Since you don't have the Endurance package, You can get a heavy duty cylinder stop spring from Wolff Gun Springs. If that doesn't fix the problem, you can get a newer cylinder that has the longer cuts and put that in. That will stop the cylinder stop from unlocking.

If you wanted to, you could get the frame milled for the bolt lock. Then you would need a bolt lock and a new hand with a longer pivot pin to operate the bolt lock. Those parts are not expensive.

 

[BMCM]

Midway has cylinder stops, both factory S&W and Power Custom oversize.
But...

Before going about replacing parts, evaluate the piece for excessive cylinder end play and correct that. You can also pop the sideplate and check to make sure there is no gunk or debris gumming up the cylinder stop or it's spring or interfering with full cylinder stop engagement with the cylinder.

What your experiencing is called bolt jump. If there is too much end play, your cylinder under recoil shifts forward and can bump the cylinder stop out of the stop notch allowing the cylinder to freewheel.

You may note that S&W around 1989 lengthened the stop notches on the 44mag revolvers at the 29-5 and 629-3 engineering changes to specifically to address this issue.

Cheers
Bill

 

[steelslaver]

Ya, first make sure you have about .001 endshake, next clean an new stop spring.

With 5K of heavy loads it probably has some endshake.

 

[BigMuddy]

I put the heavy cylinder stop spring in both of my 29-2’s and it fixed this problem in both.

Dan

 

[Pisgah]

Install an extra-strength cylinder stop spring. That has cured two 29-2's for me.

 

[Pocketrocket]

Spring

Ok guys thanks for the help. Id like to think the guy who put the hand in checked the end play but I'll have to check it myself. I'll get a spring ordered up. Is it difficult to replace? I've never had a side plate off but I'm a pretty good mechanic so I may have to give it a shot.

 

[steelslaver]

Good time to start learning. Revolver smiths are getting harder and harder to find. First though make sure you have a flat ground screwdriver that fits the side plate screws. The one just above and to the front of the trigger holds the yoke in and has been adjusted to the correct length so yoke doesn't bind on it. Make sure to keep track of it so it goes back in that spot.

Once the screws are out and cylinder and yoke are out. Turn the revolver over and holding it over a shop rag or something give the other side of the revolver some raps with the screwdriver handle or wooden hammer handle. It shouldn't take much and the side plate will pop off. The hammer block will fall out with it no problem. Study it now the insides now, but do not pull the trigger unless you loosen the strain screw on the main spring way up. The hammer and trigger studs are unsupported on side plate end. With the cylinder out you can not pull the trigger anyway as the cylinder latch moves forward without cylinder and blocks hammer unless you move thumb piece back. Completely loosen the strain screw and then unhook the spring from hammer stirrup. Now use a small screw driver to lift up the back of the rebound slide behind the trigger. BE CAREFUL there is a pretty fair spring inside it held by the stud. Don't let it get away. Once it is off you should be able to jiggle off the trigger if you rotate the hand back enough to clear the frame. Once the trigger is off. You can jiggle the cylinder lock out by pressing its tongue down out of the frame. Once again watch the spring.

Now all you need to do is assemble it in reverse order. LOL. The springs are tricky. But with some though and patience you can do it. Keep the flag rolled back to clear the frame as you jiggle trigger in place. When you put the rebound slide back in make sure the toggle on the trigger is in the socket in front of slide. Keeping the spring inside it and compressed enough to be able to get the slot in slide over the stud is fun. They make a tool for it, but, you can do it with the tip of a small screw driver. The hammer block. The "flag" goes between hammer and frame, the slanted slot goes on pin on rebound slide. I press it all the way up on the slot and slide the slot for it in side plate along it until slide plate is in place. Might take you a couple tries the first time or too.

If you take the hammer out you must slide the thump piece back. It is spring loaded and stays forward without the cylinder and blocks the hammer from moving. You must rotate the hammer back a bit so its nose (firing pin) clears the frame in order to jiggle it off.

Have fun. There are some videos out there that are not to bad

This one is pretty good, Newer gun, your hammer stirrup won't come off the hammer like that and no need. DO NOT remove the bolt for cylinder, No need,. The toggle on your earlier trigger is pinned to the trigger, where later on in video is not. No need to take it apart or remove hand. At the end he takes out pin and removes frame mounted firing pin. Your firing pin is mounted on the hammer.

Assemble pretty much in reverse order. Its easy after the first 20 times or so.
[ame]https://www.youtube.com/watch?v=G0erUfTdfXA[/ame]

 

[WR Moore]

Apparently my earlier post disappeared into the ether.

Back when the cylinder rotation was common place, I never saw an example where it didn't have excessive endplay. You'd be wise to also check yoke alignment.

Pick up a couple of those cylinder stop springs. If you're not careful you can kink them and cause problems. Insert the spring into the hole in the stop, then carefully slide the stop into place. A small screwdriver to help get the spring started and then aligned with the hole in the stop is needed. Or at least it was for me.

 

[steelslaver]

Apparently my earlier post disappeared into the ether.

Back when the cylinder rotation was common place, I never saw an example where it didn't have excessive endplay. You'd be wise to also check yoke alignment.

Pick up a couple of those cylinder stop springs. If you're not careful you can kink them and cause problems. Insert the spring into the hole in the stop, then carefully slide the stop into place. A small screwdriver to help get the spring started and then aligned with the hole in the stop is needed. Or at least it was for me.

I agree that end shake is a likely culprit. The bottom of the cylinder's stop notch is rounded as is the top of the stop. If the cylinder jumps back enough under recoil the front of the notch will hit the front of the stop and as this is happening at high speed and energy equals mass times velocity squared it don't take much to over come the stop spring and pop the stop down enough to clear the notch

Cylinder endshake is very is to check and fix. Press cylinder back with fingers and check to see the largest feeler gauge that will go between face of cylinder and barrel. Measure again pressing cylinder forward. The difference is your end shake. You need a little bit for cylinder to rotate freely but .001-002 is plenty

I much prefer the hardened shims over stretching the yoke. A smooth hard surface between end of yoke and bottom of cylinder's hole functions as a bearing. I have never ever seen or hear of one breaking, despite a few doom sayers.

 

[TIMETRIPPER]

A friend had the same cylinder unlocking issue with his 629-2. He called S&W and they sent him a shipping label with instructions on how to ship it back to them. Took a couple months and $80 but all was good upon return. This was around 8-10 years ago.

John

 

[DWalt]

I have a similar problem with my 29-3, but only with heavy loads. It doesn't bother me much because nearly all of my shooting is with lighter handloads. I once tried using a stronger cylinder stop spring but it did not cure the problem. At least for me, not enough of a situation with the 29-3 to cause any heartburn. I have a Ruger Super Blackhawk if I want to shoot full power loads.

 

[steelslaver]

One could also adjust the stop so that it went all the way up in the cylinder notch. Measure gap between cylinder and bottom of frame. Measure depth of notched. A piece of soft lead tapped with a hammer would give you a way to accurately measure this. Then the amount the stop raises from its slot in frame. Looking at the stop in the frame will show you where to file. I believe that they now make extra strong stop spring.

But, as I have gotten older I have also abandon the urge to fire maximum magnum loads. 1400 fps from a 240 gr slug will not kill anything any deader that 1200fpsw and the trajectory advantage of the 200fps is minimal

 

[armorer951]

If the cylinder stop is not fully engaging the slots in the cylinder, there is an adjustment boss on the top of the cylinder stop. Removal of material here will allow the "ball" of the stop to protrude further through the frame, and thus go deeper into the slot in the cylinder itself.

note: Be sure you examine and clean the slots in the cylinder well prior to measuring or adjusting the cylinder stop travel by this method. This is another important area that is often neglected, and needs attention with a toothbrush and solvent during regular cleaning.


Images of the cylinder stop.......








Carter

 

[BLUEDOT37]

I found my M29-2 had the same problem several years ago, unlocking & rotating back a chamber after recoil.

It too had excessive endshake & adding a couple shims/bearings fixed the problem.

Now it's back on the active-reserve list.

.



.

 

[GBertolet]

I had put the Wolffe extra power spring, on my cylinder stop. It did the trick. Probably not a permanent fix, but for the time being, it does the job.

 

[dsf]

I posted about this before and I think I have identified the problem. I have a 29-2 that has 5-6k heavy loads through it. It has an excellent trigger and no turn line, it had an action job done by Frank Taber in the SF bay area when new. The problem is the cylinder unlocks on recoil. It doesn't swing open, but after firing the cylinder is unlocked between chambers. I took it to a local place but do to poor communication ( i.e. the gunsmith didn't bother to call me as instructed ) it's still not fixed. He replaced the hand assuming it was a carry up problem. I picked it up and fired it, same problem. I put a few cylinders through it to try to figure it out. After firing the cylinder was loose and would rotate. I'm guessing the weight of a full cylinder caused it to rotate backwards and on the subsequent shot the hammer fell on the already fired round. I'm think I need a cylinder stop and maybe a heavy duty spring.

Anyone have any input and possibly a source for the parts?
I checked Numrich but doesn't look like they have them.

I had a similar issue and as others have mentioned, stronger spring and ensuring clean stops, and dressing down the boss on the cylinder bolt just a bit cured the issue.

I really haven't found a frustration free way of wiggling out the old spring. I found that slipping in a new was helped by a thin sheet of metal vertical to shoehorn it in.

I haven't heard Frank Tabor's name for a while. I did alot of buying from him before he retired and closed shop in San Bruno. He did some gunsmithing work for me. Nice guy, once you got to know him.