LAR45 on rereading your post all you said was a heavy slug gun??? I just thought that to say a rifled shotgun ??? Be kind of like the 12 bore rifles of old. Cool Huh. But others on the board talk of rifle rounds???? What ever way you go I think you should keep studying on . I still think you could make a nice one off gun here. If it is soft steel like said above case harden it. Would be pertty ..As a dumb butt I don't know if recever ring strenth is as big of a deal. I would worry about the breech block and fireing pin design???