Yes clapper you are probably right. It is likely an 8 bore gun, there is no way to mount it on anything it is definitely a shouldered gun. As stated earlier breach measurement from the outside is 1.320, cannot measure the inside, so i'm guessing logically it would come in around an 8 bore maybe a 6 but hard to tell.

any value to these guns....? and who is buying them and for what reason.....?