.54-caliber percussion side hammer carbine, with 24.5 round barrel and full-length stock secured by two barrel bands. Lock case-hardened, barrel browned and furniture of brass. Lock marked "N.P.Ames/Springfield/Mass.". Barrel stamped "Wm.Jenks/USN" followed by inspector's initials. Buttstock carries an inspector's cartouche. Approximately 4,250 made between 1841 and 1846. Some marked "USR" for "U.S. Revenue Cutter Service". These would bring approximately 80 percent premium over values listed. However, prospective purchasers should secure a qualified appraisal prior to acquisition. Premium for first variation with no sling ring behind triggerguard and round (instead of oval) slot for round ball.