Ames manufactured only 4,250 of these distinctive "mule ear" carbines between 1843 and 1846. "Wm. JENKS" and "USN/RC/P/1846" are marked on the top of the barrel at the breech ahead of the oval loading aperture. Small inspection marks are on several components. The lock plate has the Ames three-line marking in the center and "Wm JENKS" towards the rear. A sling ring is mounted on the lower tang. The stock has an inspector's cartouche on the left flat.