Jim,
Yes we know exactly what you mean and it's possible but most agree not worth the trouble. There's been a ton of discussion over this issue.
I don't mind the cyl ring at all but I do mind an excessively rough cyl stop bolt (many are rough on new guns right from the box) from gouging a groove into the cyl.
So I simply polish the bolt on all revolvers when I first get them. Takes one minute with a Dremel tool and goes a long way towards mitigating the ring. After that, I never think about the ring again.
If the ring really bothers you, there’s a cyl bolt plunger (in the hammer) modification that will eliminate the ring on new models from normal cocking. However, recognize w/o conscientious handling of new models, modified guns can still cause a ring.
Even if the hammer plunger is modified you can cause a ring if you drop the hammer w/o cocking all the way back 1st (a SA no-no!) or when you close the loading gate w/o a cyl notch being directly above the cyl bolt; as soon as you cock the hammer or turn the cyl into place to lock it, you scribe a ring just like on an old model.
That's the reason on unmodified guns that the line goes all the way around the cylinder. Because the cyl bolt only scribes a line starting 1/2 way between the notches in normal cocking and firing. The rest of the line is caused as stated above.
As you can see it can be futile trying to avoid the line.