A number of pistols like this were recovered from the 1715 Spanish Plate Fleet off of Ft. Pierce, FL during my tenure as a conservator in the Bureau of Archaeological Research's Lab. They were all iron mounted as is this one. One of them had been shortened and a belt hook added. The bore size was .615 and the barrels were all 16" in length (oct/rnd), except for the one that had been shortened.
James Levy