If you don't mind me hijacking your thread Dana, i would like to post a Portuguese shoulder gun, said to be from the first half 17th. century, with a rotating cylinder system. It is part of a private collection in exhibition at the Oporto Military Museum; or it was, as the last time i have been there, i didn't see it; Museums can be mysterious some times
.
The pictures are horrible and i don't have full info about its functioning, but it appears that some of the details are ingenious.
.