[quote=notsofast;140234717]Following....
OP when you get a chance let us know about this "drag" thing. Hope you didn't go shoot it this weekend and have a round go off out of battery.
Strange. The original problem sounds like failure to index "carry up" since it does it for you in SA. FTCU can allow the cyl to rotate back to the previous cyl stop position. A weak cyl stop spring can do the same thing after the round goes off.

Adding "drag" would tell me the cylinder is still unlocking so the issue is not correctly fixed. Adding "force" as in additional spring strength I would buy into. Or mechanical adjustment would fly too.

My suspicion... Probably stacked up end shake shims till the cyl started to bind a bit. Bad "fix" if that's what was done. If the gun is still having an indexing issue. Additional "drag" does not fix a mechanical unlocking situation all it would do is attempt to keep an unlocked cylinder in position while the hammer drops. The cyl either locks in or it doesn't. If it doesn't I wouldn't shoot that gun.

Sit and dry cycle it for a while, at the same time trying to turn the cylinder by hand during and after each trigger pull to make sure the cylinder is LOCKED in place on each cylinder stop notch.

If it rotates off the cylinder stop or hand you still have a problem

__________________
R/S
J.D.

I don’t understand why the OP didn’t send it back to the mothership a one more time.

For starters it costs over $100 to ship it there. But more importantly they had pronounced it ‘fixed’ the first time and didn’t improve things one bit. I’m not about to ship it to them three or four more times to get it right.

As it is, I had to bring it back to my local gunsmith three or four times before *I* figured out the problem, and he fixed it.

I will call him tomorrow to ask him exactly what he did to induce drag in the cylinder. It feels normal to me now. I guess before it had been completely slicked up as part of the trigger job and was TOO slick for reliable functioning....

[quote=JDinAZ;140235360]To be clear, the gun is not, and never was unlocking during firing. This whole time that was my belief, but I was mistaken. I finally discovered that the gun was malfunctioning during the cocking phase (single or double action). When the hammer was drawn to the rear and the hand was indexing the cylinder to the next chamber, occasionally the cylinder would simply spin two or even three chambers on its own. It was no longer locked, and the hand didn’t have enough drag to keep it from freely spinning when it was imbalanced (with three empty chambers and three loaded chambers). Eventually as the hammer neared the rearmost part of its travel, the cylinder would lock up and the gun would fire normally.

The malfunction manifested when the cylinder would spin past an unfired chamber, and wind up presenting an already-fired cartridge, resulting in a big CLICK when the trigger was pulled....

[quote=Pantera Mike;140236329]this still means the cylinder stop wasnt working properly

[quote=Bobafett;140236392]The cylinder stop doesn’t raise back up until the hammer is partway back during the cocking cycle. Well-used guns will have scoring on the cylinder where the stop drags against it. But those marks don’t run from one notch to the next. Normally the stop doesn’t rise up to touch the cylinder until the hammer is at least 30% or more through its travel. There is no contact for the first part of rearward hammer travel, and that is where the cylinder was rotating.

I have several other Smith revolvers, and experimented with them. If you slowly cock the hammer while attempting to turn the cylinder counterclockwise with your other hand, all of them will allow it and you can turn the cylinder freely. It’s just the way the mechanism works.

[quote=Pantera Mike;140236401]just tried 3 revolvers right in front of me and none rotate freely, sure i can move them out of 'time' but none can i rotate to the next cyl hole. is there no tension on your cyl hand? that should never let go

[quote=Bobafett;140236415]You’re doing it wrong then.

I just did it with a model 1905, 686, 29 and 629. Try cocking the hammer slowly while watching from the side. When the cylinder stop drops into the frame, the cylinder can spin freely, but of course only in one direction. The hand drags against the cylinder and it clicks as the cylinder rotates. If you are trying to spin against the hand it won’t turn. If you spin with the hand, it does.

[quote=Pantera Mike;140236418]No i follow you Mike, there is resistance, I'm just not going to force the hand to click off the extractor

[quote=Bobafett;140236421]In my particular case, the gun was doing it on its own. I’m no gunsmith but if I had to guess at a fix, I would say the hand needed to be bent outward so that it would more positively engage the back of the cylinder to prevent unwanted gravity-induced rotation. I will find out if indeed that was the fix.

One of the things that stymied the gunsmith was that the gun functioned flawlessly when it was empty. I decided to test my theory by loading three dummy rounds, with 158 gr .357 bullets inside the cases instead of powder. This would exaggerate the weight imbalance between three full and empty chambers, and in this condition, my malfunctioning gun would routinely skip. Meanwhile my 629 worked normally.

It was interesting to watch as I slowly pulled the hammer back on my 29 and heard and saw it go ‘click click’ as the cylinder rotated on its own. It was a big “A-ha” moment, particularly as all this time we had both assumed it was coming out of battery during recoil.....

I find this thread interesting but I have a question for Mike0251.

How did you use shims to tighten the cylinder/barrel gap from .009" to .004" ? I'm very surprised nobody else has asked this.

My impression is that the only way to do this is by putting shim/shims in the extractor star area and that is a no-no.

Am I wrong ????