This rifled musket started out life as a flintlock smoothbore 1816 musket. With the development of the Minnie Ball in the 1850 and the adoption of the Maynard tape primer system in 1855 alterations to update older muskets were undertaken. Frankford Arsenal performed alterations for the US government and the State of New Jersey contracted with the arsenal to alter muskets for the State. Remington supplied the locks and breechplugs for Frankford to use in the alteration. The alteration process started in 1856 and by 1859 20,000 muskets were altered for the national government. In addition in 1858 1,300 were altered for the state of New Jersey. Or the altered muskets 13,189 had rear sights installed and the rest did not have a rear sight. The conversion process consisted of sawing off the old breech and fitting a new breech with a percussion bolster. The barrel was rifled and a new lock was added with the Maynard primer lock. This particular example is marked "NJ" on the barrel and on the stock. While this musket could have been one of the ones made specifically for New Jersey, it also could have been one of the 20,000 made for the national government and issued to the sate at the start of the war.
There is no rear sight on the barrel. There is some pitting on the barrel in the bolster area but mainly the metal is a nice clean condition. These rifled muskets were issued early in the war and saw extensive service.