Ames manufactured 4,250 of these distinctive "mule ear" carbines between 1843 and 1846. They are among the earliest percussion arms used by the U.S. Navy. This carbine has the rifled barrel and oval loading aperture found on later production carbines. The front sight is an integral part of the upper barrel band. A sling ring is mounted on the lower tang behind the trigger guard. "W.JENKS" is stamped in small letters on the top of the barrel parallel to the bore followed by "USN/RP/P/1844" perpendicular to the bore. Small "P" inspection marks are also on several components. "N.P. AMES/SPRINGFIELD/MASS" is stamped in three lines on the center of the lock plate, and "Wm JENKS" is stamped on the rear of the lock plate. The left stock flat has "RP" and "JL" cartouches.