I am new to the forum so if this has been covered recently please direct me to the thread.
I purchased this 64-1 that has been converted to a PPC competition gun. Has extra heavy slab side bull barrel with Aristra Crat sight bar, trigger work and a very nice black finish. I have been shooting mostly wadcutters but a few standard rounds just to check the accuracy. It was fine with the first 200 rounds or so but now the cylinder seems to bind with the barrel when trying to pull the hammer. Its difficult to get a .004 feeler gauge in, even when pulling back on the cylinder. There is no perceivable front to back movement with the cylinder locked in place.
Any thoughts ?

It may seem pedantic, but, have you cleaned the gun after that first 200 rounds ? Carbon builds up on the face of the cylinder (of a revolver) when fired. If your 64-1 has a tight cylinder to forcing cone clearance, carbon build-up could easily cause the binding problem.

Check for black carbon rings around the charge holes, on the front of the cylinder, if you haven't already. If you have a build-up, remove it. There's a good chance that this is the problem.

A black-finished gun, as you describe, will make it much harder to see the build-up when it occurs.

A 0.004 cylinder gap is snug.

Is there enough carbon build up on the forcing cone to cause binding of the front of the cylinder against the forcing cone. If so a cleaning of the forcing cone and front of the cylinder would help.

I suggest checking the gap between the cylinder and forcing cone on each side and if different you may have a bent yoke.

Are you able to easily open and close the cylinder? If not the ejector rod may be loose and need to be tightened (screwed in).

Are cartridges binding between the cylinder and the recoil shield on one side. Load with spent cartridges and check. If so, then a bent yoke is likely.

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Scoundrel & Ne'er-Do-Well

Have you cleaned it real well. Pay attention to the rear of the forcing cone, the face of the cylinder and under and around the extractor star. Make sure you eject empties with muzzle up as it helps keep firing debris out from under star. Even a little debris under the star makes the cylinder assembly a bit longer and makes it press harder against the recoil shield and makes the cylinder press forward toward the forcing cone and yoke. A little lead/carbon built up on the forcing cone and cylinder faces can also cause drag. With 3 spaced empties in the cylinder check to make sure the ejector rod is tight. A S&W of this era has left hand threads on the ejector.

This gun was setup for competition shooting and probably has minimum clearances and will need to be cleaned often.

I'll add this suggestion, and it's something that should be checked first with any S&W revolver that begins to bind, or if the cylinder becomes hard to swing out -- check to be sure the ejector rod is screwed all the way in. And remember, it's left-hand threads, meaning that you have to turn counterclockwise to tighten.

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Pisgah

Try pulling the trigger back just enough to drop the cylinder stop out of engagement and see if the cylinder while holding the trigger carefully in that position will rotate freely.........it should. If it does rotate freely you may have the hand binding on its upward travel.
You didn't by chance change grips did you? If so you may have a bind against the main spring where the grip screw passes through.

Karl

Remove FRONT SCREW & remove Cylinder & Yoke. Disassemble Cylinder from Yoke, clean both thoroughly. Flood hole where EJ goes into Cylinder with Rig #2, Remoil, or similar (a very thin cleaner and lubricant) blow out with compressed air or just shake thoroughly, reassemble everything. This might just do it! No need to completely remove all carbon from face of Cylinder, but make sure you have no heavy lead build-up. If you do, take some off but don't get too crazy trying to remove every last bit of Carbon.

great info, thanks. i had considered the carbon or lead build up as most of you mentioned but I did recheck to be sure. I used a scraper to check the forcing cone and did find a very small amount of build up. Nothing on the cylinder and the ejector star looks clean with no build up behind it. The cyl. swings easily and turns free when pulling the trigger a little as described. The ejector rod is tight and it has a bottom grip screw mod. I don't think this gun was ever used in competition but built and put into a collection. After all this, I noticed that that it would cycle really well in DA but when pulling the hammer back it would bind most times, but not every time. Paying better attention, it seems the hammer may be binding rather than the cylinder. I doused it with gun oil and seemed to improve things but still binding sometimes. Maybe I should pull the side plate and have a look ?

If binding when pulling hammer back may be interference with return spring housing hitting against mainspring. Yes, pull side plate, and slowly pull back hammer and watch travel of return spring housing possibly hitting against mainspring.
Certainly if cylinder is spinning freely with partial pull of trigger with cylinder lock dropped it is not the cylinder binding on forcing cone. Pulling hammer back manually is more travel than hammer goes through with a double action pull.
Most often these competition guns are DA only. Does this gun cock with a single action pull back of the hammer?
Karl

.004 gap is tight, but it is not your problem. Check for any deposits between the cylinder and forcing cone.
Other than that, it sounds like you have a bent crane. Any good gunsmith can install a new crane assembly and fit it to your gun.
You can also ship it to Smith and Wesson, they will the best source for fixing your problem.

Good Luck

This gun will cock with pulling the hammer back and I do shoot it this way. I think, in the police pistol competition it was fired in DA only. Its possible that it was meant to be fired in DA only and I am doing something that was not meant to be by firing in SA. Not sure, just thinking. I will pull the side plate and have a look. I have the full set of gunsmith kinks books from Brownells so maybe something there I can reference.
Thanks again for all the feedback and a pic of the gun added