There are several aspects to the cylinder ring issue:

#1. POLISHING THE CYLINDER BOLT: For all SA and DA revolvers - the single most important preventative action you can take and the 1st thing I do on any revolver of mine, new or used is pull the cylinder (or open it, in the case of DAs) and polish the cylinder bolt! They all come with file marks just waiting to carve out a line and groove in your cylinder finish!! This is especially true on stainless which is relatively soft and therefore similar to aluminum when it is machined in that it has a tendency to gall like those little cuts or chisel marks from a sharp edged Cyl stop.

With a VERY FINE abrasive wheel in your dremel tool, polish out the file marks and then with a felt buffing wheel and white rouge (for stainless steel) put a mirror finish on it. Don't forget to mask off the frame and breech face all around the bolt with duct tape because the dremel will slip off the bolt. And don't over do it unless it needs reshaping anyway to better fit your cylinder notches. If you do nothing else, this is the single most important thing you can do to avoid that ugly cylinder ring!
And it has delayed the bolt from even wearing all the way thru the bluing on a new gun for years of shooting on some of mine.

#2. NEW MODEL RUGER SAs: Mostly you have to rely on #1. I have blue Ruger SAs with barely a noticeable line not even thru the bluing after hundreds of Cowboy Shooting matches. The Ruger bolt, by engineering design, rises up far too soon to hit in the approach ramp to the cylinder notch. Before closing the loading gate on new models, make sure to turn the cylinder by hand so the notch is aligned above the bolt to minimize the bolt rubbing on the cylinder surface.

#3. COLTS, RUGER 3 screws and Similar: First priority: proper handling of these old design SAs is the secret. Then rely on #1 above for insurance especially for Rugers; again by design the bolt comes up too soon! Most do not realize that once you cock the hammer of a properly timed SA, you MUST COMPLETE THE CYCLE!! Never drop the hammer from safety notch or half cock; always cycle all the way thru the full cock position and then let the hammer down. If you don't, you get the same effect of the new model Rugers above: the cylinder has not been moved thru its full cycle which allows the bolt to pop up on the cylinder surface. Also, bolt springs on these older design SAs are always too strong! Use an after market lighter spring. Just don't go too light or under hard and fast cocking, you can slam the cylinder notch right past the bolt with potentially ugly results when the trigger is pulled. I have Colt's that I've shot for years with no ring on the cylinder at all; only a shiny spot in the approach ramp to the cylinder notch.
UPDATE: Last month I tuned up a newly purchased, brand new out of the box Colt SAA. I was amazed to discover that the cylinder bolt had a mirror polish on it from the factory. I also noticed the hammer spring was tapered and of lighter weight. The factory confirmed the new spring is now standard issue. I don't know about the polished bolt yet but at least one smithy at Colt got the idea!

#4. DA REVOLVERS: Rely on #1 above! Like Ruger SAs, even with perfectly timed actions, by design, the bolt on DAs is raised early in the cylinder cycle. Eventually you may get a line on DAs and Ruger SAs, but it should never be completely around the cylinder; only 1/2 way to the next cylinder notch. A simple habit when you close the cylinder, with your left hand grasp it around the bottom of the frame with thumb and forefinger in opposing flutes positioning them at 3 and 9 o'clock when closing the cylinder will prevent scribing and becomes so natural after a while, one doesn't even have to think about. Works on five shot cylinders as well by positioning two flutes at 4 and 8 o'clock. Once closing the cylinder in alignment becomes a habit which is like after the 2nd time you do it for most of us, it's no "effort" what so ever; or about as much effort as remembering to breath. This WILL mitigate a full cylinder ring and at least limit it to an interrupted ring.




ONE MORE LITTLE TIDBIT TO PREVENT CYLINDER SCRATCHES:

Misc. circumference scratches that appear on single action cylinders can be caused while removing and replacing the cylinder for cleaning. A simple technique can easily avoid them. Cut a strip of paper about 8" long and the width of the cylinder. Insert it around the cylinder before removing the cylinder pin. Once you pull the pin, you can lift the cylinder out of the frame window by the paper and not have to worry about making contact with the edges of the frame. This is especially helpful when reinstalling the cylinder into the frame as you rotate it past the hand and align it with the cylinder pin as you push the pin back in.

As you can tell from other posts, not all care about this issue and are quick to tell you. The cylinder line scribed by the cylinder stop is about the most obvious sign of wear. Not just a sign of shooting but also of cycling, opening for checking or loading and unloading.
These actions will not completely prevent the cylinder ring but has mitigated the ring on my guns. Now you can handle and shoot 'like new' or old revolvers with a clear conscience that you won't cause any more perceivable wear!

__________________
Jim
S&WCA #819