Hi Delmar. Looks like yer "gettin to it". Replacing the ring as you have shown in the pic is viable. You have to have a solid back up for it. The battered ring that would be behind yer replacement would need leveled off first.
Another thing is that washers are kinda soft and that might not last long. If you use a narrow rim bushing like the one you found but.....much smaller....you could make a hard cap to your battered ring that would last longer.
Like was mentioned about the arbor and the cylinder gap and a wiggly arbor and a large cylinder gap isn't good for the ring even if it were steel. You have to end up with a min. cylinderr gap and fix the wiggly arbor. Arbor first...then the steel back plate or your patented
"ring cap".
Your ring cap can work if the original is leveled and the cap is hard. I'd imagine it would be better to get rid of the originl battered ring all together and have a more solid base to solder the cap to.
The backplate I mentioned is easier to do,maybe, except for the shortening of the nips and gettin rid of the safety pins.
Your machinist friend would find it easy to mill the shoulders where the nipples bottom on deeper,providing theres some extra hole in front of the ends of the nips, so you screw the nips in further instead of shorten them.
I put that steel backplate on my old brass framer before it was ever shot and was new. It's a CVA..ASM made brass framer and ASM used some soft brass for those he made. It would have banged up the ring behind the cylinder even if the cylinder gap was minimum and the wedge was kept fit well and all that.
I guess some brass framers are made of harder alloy brass so they can last.They say the Piettas made today last well. Others in the past have ,as the one above post has explained. I'd wonder how much shooting that brass framer has done in the last 20 years and wonder what make it is. I'd probably keep an eye out for one.
Bottoming an arbor in the barrels arbor hole isn't too hard. Takes some patience and some "color" on the arbors end to check when it hits bottom well and hits the bottom flat.
Thing is......those guns without the bottomed arbor to begin with have the barrels cant "back and down" at the breech when the wedge tightend things. That lets the barrel go back further and sometimes pinch the cylinder from turning.
Anywhoooo.....if an arbor is bottomed then the barrel doesn't cant back and down anywhere as much and the cylinder gap then is left larger ......you know how the cylinder gap is much smaller at the top than the bottom before the arbor is bottomed? The barrel needs set back some in a case like that after the arbor is bottomed or as the arbor is bottomed. Sorta like your getting it bottomed and then realize the cylinder gap seems larger so you have to let the barrel come back a little and the frame or barrels bottom lug needs material taken off some. That complicates "bottoming" an arbor some. It's like they say,"easier said than done", type things. Not really real difficult but a little more complicated than one imagines before they "do it".
Anywhooo......there's ways to fix the old ones and get them back on the road again. I've found that, like in Smoking Guns case and the Centaure 1860 serial 767, those old junkers you find and fix become your favorite ones.
Good luck Delmar. Yer progressing from "Kitchen Table Gunsmithing 101" to "Advanced Kitchen Table Gunsmithing 101". ha ha ha