I have a friend says he has a 9MM trapdoor shotgun.I haven't seen it.He said it was made in the 1850's.When I told him that it doesn't make sense he promptly said "you calling me a liar?"I didn't think they made shells until about 1870.Can't see how a trapdoor muzzle loader would work.He says it is a smoothbore.Any body have any guess as to what he might have?