Dear Paul,

Thanks for the swift reply.
I think I know/see what S&W did with the gasring, what you nicely cal the interface.
With a bit of luck I can fix a solution/principle like that on my old 66.
You're totally right that a new cylinder and yoke will not be a simple drop in.
Maybe I get to my drawingboard tomorrow and post some sketches.

Best regards,

Hans Peter