This gun is actually very late. Backaction locks will date it to about after 1835. The style of the finales on the trigger guard and ramrod entry pipe, is after the pineapple and acorn style periods. The trigger guard style of bow, puts it the after 1850 date. As a guess, I would put this gun in the 1855-1880 period. Which is really about the last of the muzzleloader period.