Interesting. This changes the timeline a bit, since the longer .22 rounds (.22 Long, .22 Extra Long and .22 Long Rifle) didn't appear until the 1870's and 1880's. This gun appears to have been made from a 2nd Issue, which was only made until 1868 ... so I'm leaning towards my theory that someone put a more powerful round into the gun and ruptured the cylinder and/or hinge. This would have immediately rendered the gun a "project," with rather interesting results.

Mike