Cap,
That explains it very well, sir. The inner ring was pretty much a no-brainer (to me) but the outer ring eluded me until you explained that it was basically the recoil shield in its entirety. Since the "inner" ring is a machined part of the frame, I take it your thin steel "washer" fits between the frame inner ring and the cylinder? Your photo #2 illustrates the flat on the inner ring, same as my G&G. Why that is I have not a clue compared to the steel frame pistols. Mine are all Piettas, you may have another model.
Just curious, but even with a thin steel washer, how is that going to obviate cylinder battering against the inner ring, unless you feel the steel washer won't impact the inner brass ring very much? I would think that it would not change anything unless the geometry of the cylinder rear face impacting the steel washer is different than impacting the brass inner ring.
I am not downing you and your endevors. I am rather curious as to how it turns out.
Good luck, sir!
Jim