NitroX,

My small bore DR's are all on frames the size of a 28ga. shotgun. I measured them against a 28ga. pre-war J.P. Sauer I had, and they matched, including firing pin spacing. Of course, they are rifle frames, not shotguns, but that is the correct size for the purpose.

What shotgun action makes a good "donor" and what size, I don't have a clue. It seems that good small bore shotguns come pretty dear these days. Instead of wrecking one for a home-made rifle I think one should just consider buying the rifle.

Interesting concepts, though.

Best,
Curl