Steve: I don't know much about them. I suspect you've found a few of them!!! I looked through a few books after getting it but no luck. For some reason in the back of my head I had it that they were made for use by the Navy for some of the bigger guns (32-lber, 42-lber) that were left over from the war of 1812. For the cannons such as the Brooke rifles made during the war, they were fitted to used hammer locks. I would imagine the pan at top was filled with powder and lit with a port fire or possible stuck with a hammer. But I don't know. I hope someone can provide some education for me. I have seen a few over the years but no distinct memory of where they were recovered or details on use.
