If the cylinder is locking up just before the hammer releases in double action it is good. Wouldn't take much more and trigger would bind before it released the hammer. The difference enough and to much is slight. I would check for end shake before doing any action work. How much does the cylinder move forward and back? If there is a significant amount as the gun is cocked the cylinder moves forward and farther from the hand so it can slide by the ratchet tooth quicker. A cylinder shim or 2 may be all it needs. If the the cylinder stop is engaging the cylinder and preventing it from turning it is fine. Some small amount of movement while in lock up is also acceptable. As the bullet leaves the chamber throat and enters the forcing cone it brings the chamber into perfect alignment. If there is excess movement it comes from peening in the cylinder stop notches (usually the far side, not the lead in side, as it stops the cylinder rotation). This can be peened back into place. It could also be slop of the cylinder stop in its frame slot.
But, don't go putting parts in it until it has been checked by someone who really works on S&W revolvers. Your post gives no information on your experience with them. Your thought of just replacing the extractor tells me you haven't got much as extractors very seldom work on cylinders they were not made with. Until the recent pinless design change the extractor and cylinder were match drilled as a set during assembly. The holes in one extractor star very seldom line up right on a different cylinder. Even a tiny bit of difference and it hangs up. I have had zero luck at it and I have a drawer full of various cylinders. There is a couple work around, but it isn't that easy. Someone with a small lathe and the right knurling attachment can redo the knurling the tip of your rod, BTW
More important is how does it shoot?
Thank you for all that input. This is exactly what I'm looking for. And you're right, I don't have a lot of experience with this ....yet.
My HOG chapter did 'A Night at the Range' event last November and my friend offered to let me take/shoot this weapon and his semi automatic S&W #39-2 made `75 -`76. The only stipulation was that I would be responsible for cleaning them. What he didn't tell me was neither weapon had been cleaned in over 10 years! So, they both went to the range dirty. The revolver fired OK but, I could tell it wasn't moving 'right' and the semi failed to completely eject the casing (twice) and jammed. I used YouTube to learn how to disassemble and clean these (BTW, you watch enough videos and you figure who knows their stuff and who the goobers are). It was only then I realized how dirty they were and thought "no way they got this bad with just 'one' trip to the range." So, I called my friend and asked " Bob, WHEN were these last cleaned?" He paused and said "Well, it wasn't this decade.".... I wanted to smack him!
His motivations were three fold:
1. He knew I'd been on the fence about owning a handgun for years and he wanted to knock me off that fence.
2. He knew he wanted me to have these guns when he died so, he wanted me to start getting some experience with them.
3. He knew my skill set and had every faith I would figure out 'how' and clean them right. I.E. he got free cleanings out of the deal. BTW I also inherited his 70s vintage gun cleaning kit. But I had already restocked the cleaning pads and cleaning fluid (that bottle had evaporated).
The end shake is so small, a single .002" shim would bind it. The stop notches look fine. I just checked the operation again and based on your input, this is OK to fire. It's going to the range tomorrow. I'll have it looked at by a professional when I find one I can trust. My go-to guy passed away on Jul 3.
I'm beginning to believe the term "Hindsight is 2020" was coined by a future time traveler and has been a message we've misunderstood.