I can find no reference to your musket for US as in military use or issue. This is strange as the US designates it as being a contract gun. Due to it's longer pinned barrel, 44" as opposed to most contract and Harpers Ferry as well as Springfield guns having bands, I wonder if the lock might be a replacement for a gun surviving the recolutionary war. By this time, 1810, all military US guns I can find pictures of, have bands and 42 to 42 1/2" barrels of .69 cal. : On the other hand, there were a number of Mexican Bess's, but were normally marked with the Mexican Coat of Arms. These were pinned but had round holes in the cock's throat. I have one picture of 5 US model contract arms, from 1808 to 1840 marked 1842 - all being Flintlock and having bands as well as double throated cocks with round holes. This includes one Harpers Ferry musket of 1795 pattern, but dated 1809 as well as an Eli Whitney marked "EXETER" on the lock of M1812 & a M1816 made at Harper's Ferry yet even the 1795 had bands instead of pins. All of these were .69's, yet the issue ball in ctg. wa .64 in calibre(at Lewis and Clarks time) this windage was reduced slightly later on to improve accuracy. The standard ctg. charge for the .69's was 167gr., (10approx)of which was sprinked into the pan for priming. Later on as powder quality improved, this charge was reduced to[url] 130gr.in[/url] the ctg. : Very strange musket you have there and a treasure for certain.