The Model 1842s were the last smoothbore muskets manufactured by the U.S. national armories, were used in the Mexican-American War and Civil War, were manufactured with thicker barrels on the assumption that many would eventually be rifled, and many were rifled during their service life making original smoothbore examples like this desirable. This model was also the first martial arm manufactured by both Springfield and Harpers Ferry with fully interchangeable parts. This "1847" dated example has standard markings and features and includes a "US" marked socket bayonet.