There are no proof marks on the barrel flats. In an out the only marks are 6 & C. It has alway been percussion. If you look closely at the pictures you can see traces of rifling oi the bored barrel. Thought it might be a Cape Gun but 99% sure it started out a double gun. I keep hoping someone will see the letters visable and a bell will ring on the maker. Thanks for you comments Tom

Suppose you were an idiot and suppose
you were a member of congress. But I repeat myself - Twain.