This is a U.S. Model 1816 Type lll Flintlock converted to percussion. It has a 69 caliber bore with a 42” barrel. The mechanical function is very good and tight. The bore is about very good, shiny .69 caliber smooth bore. Only the first 8” at the muzzle has light frosting, the rest is nice. The left side has two very good inspector cartouches. The barrel has the V with eagle and P proof marks and all are crisp. The lock is marked Spring/field/ 1839. Most all of the type lll were converted to percussion during the Mexican American War and prior to the Civil War. A .64-.65 patched round ball for accuracy works very well.