I bought a Model 66-2 3" at a gun show without looking closely at the gun and it was a beater. On round 1 at a good gunsmith, the endshake was reset, a new hand and timing, and a few internal parts were replaced, the forcing cone was recut and a few other adjustments were made. The gun is now a good shooter, accurate, and seems to be safe. There is a little looseness when I move the cylinder side to side. My other 66 is very tight with only a little movement. It seems to be more on the front end than the back. I found that the locking bolt at the front of the ejector was sticking and I lubed it. It doesn't seem to push into the ejector rod like my other Smiths. An armorer friend thought that maybe the cylinder
stop was worn. Any suggestions on what I should check and/or replace to tighten things up? I may end up sending it to the gunsmith for round 2.

Some side to side play is perfectly normal. It has to have a little tolerance to assure that the cylinder stop locks fully into the cylinder notch on each chamber as dirt, carbon and lead collect. As long as it locks up tight when the trigger is pulled, and as long as each charge hole lines up with the forcing cone you are fine. That can easily be checked with a Range Rod. Some guns are a little tighter or a little looser than others - it does NOT mean there is a problem. If there is (what a gunsmith deems to be) too much or excessive play a new cylinder stop can be fitted which will tighten it up.

it is also common to have some positions on the cylinder slightly tighter than others. Just the way they are.

Instead of driving yourself nuts, take it out, shoot it and then you will KNOW if there is a problem.

Chief38

Thanks Chief. I am probably over thinking this wobble in the cylinder. I'm sure that my gunsmith checked this stuff when he adjusted the new hand and timing, he is very thorough. He felt like it was a good shooter. I have fired it several times since I got it back, and there is no sign of shaving lead. It seems to shoot without issues. My other two Smiths are really tight and haven't been shot much, so it may be unreallistic to compare this gun, which obviously was shot a lot. I really want one last, nice model 66 to remind me of my early LEO days. I thought this gun could be the one, but it may not be realistic to try to build this one into that mold. But....

IMO people read "bank vault tight" in the internet and start overthinking things on their personal revolvers. The S&W revolver is and was always intended to be a Combat Revolver and with a Combat Revolver a bit of loosness is desireable. The simple fact is that if the cylinder stop details, the hand details, and cylinder pawl details were perfectly fit with clearances of about 0.0003 inch you would end up with a bit of detectable movement at the cylinder and a gun that started to malfunction after 6 or 12 shots because of powder fouling. Our revolvers feature Forcing Cones because it's a necessary feature of a Combat Revolver. The Forcing Cone allows proper function and very good accuracy even when the cylinder fires as much as 1/64 inch or so out of alignment with the barrel.

I agree with Chief38, you really only need to be concerned if you see evidence of a problem with alignment. If your model 66 is accurate and not spraying you or your range neighbors with debris I wouldn't worry a bit if it's a bit looser than some of your other revolvers.

I believe you guys and I think that I will stop worrying about the wobble with the cylinder. I was going to have my gunsmith do whatever is necessary to tighten it up, but I suspect that this isn't worth trying to improve. He gave the gun a clean bill of health and it shoots ok, with no sign of problems. I appreciate the input and the additional opinions.

Again, there is a basic misunderstanding of how a S&W works.
In the S&W, Ruger, Dan Wesson, and the later Colt's like the King Cobra, the cylinder is deliberately designed to be slightly loose on ignition.

This allows the bullet passing from the chamber to the bore to force the chamber into alignment with the barrel.
In order to function correctly these revolvers MUST have slightly loose cylinders. Some specific guns may seem to lock up tight, but they all have enough backlash built into the action to allow the cylinder to move enough to align properly.

In these revolvers, testing the cylinder for rotation with the trigger held back IS NOT A VALID TEST FOR ANYTHING.
The only double action revolvers that lock up tightly with the trigger pulled are the older Colt action models like the Python, Detective Special, etc. This was Colt's famous "Bank Vault Lock up". The Colt's are tested for proper lock up by holding the trigger back and checking for cylinder rotation movement, of which there should be none.

There is no factory specification for how much cylinder looseness is acceptable, either with the action at rest or at ignition.
The ONLY test for cylinder looseness is: Is the gun accurate, does the cylinder stay locked, and does it spit bullet metal? If it's accurate and isn't spitting metal and the cylinder won't roll out of lock it's good.

Bottom line, in a S&W and most other DA revolvers the cylinder MUST be loose at ignition or it won't work correctly.