William Jenks received four U.S. Navy contracts for his distinctive "mule ear" carbines and contracted Nathan P. Ames of Springfield, Massachusetts, to manufacture the 4,250 of carbines between 1843 and 1846. They were among the earliest percussion arms used by the U.S. Navy and are the only "mule ear" firearms adopted by the U.S. military. Trial reports relate that they were efficient, accurate, durable, and reliable. They were lighter and simpler than the Hall carbines, the only widely used breech loaders in use by the U.S. military at the time, and they could deliver twelve shots more rapidly than the Colt Model 1839 revolving rifles. They were in use during the Mexican-American War. The U.S. Navy commanded by Commodore David Conor and Commodore Mathew Perry blockaded and captured important Mexican ports during the war and was crucial to the American victory. The capture of Veracruz in 1847 included the first large-scale amphibious assault ever conducted by U.S. forces and opened the way for the march inland to capture Mexico City. The Jenks carbines were very likely used in the assault. The Jenks carbines were also used during Commodore Perry's post-war expedition to Japan. Most of the Jenks carbines were in storage at the beginning of the Civil War, but they may have seen limited use when other arms were not available. It is particularly likely that any in Southern arsenals were rushed into service given the South's significant disadvantage in suitable firearms during the war. "WM JENKS" is stamped in small letters on the top of the barrel parallel to the bore followed by "USN/RP/P/1845" perpendicular to the bore. Small "P" inspection marks are also on several components. "N.P. AMES/SPRINGFIELD/MASS" is marked in the center of the lock plate, and "WM JENKS" is stamped on the rear of the lock plate. This carbine has the later production rifled barrel and oval loading aperture. The front sight is an integral part of the front barrel band. A sling ring is mounted on the lower tang behind the trigger guard. It is mounted with a nearly full length straight wrist stock with crisp "RP" and "JL" cartouches on the left above the trigger guard.

Excellent plus, as issued. The barrel retains 98% plus of the bright original brown finish. 98% plus of the original case colors remain on the lock and breech. The brass components have attractive aged patina. The stock is also excellent plus and has crisp cartouches, some minor edge wear, and scattered minor dings and scuffs. The "Mule Ear" carbines have long been popular with collectors. They represent American ingenuity and are certainly oddities compared to the predominant arms of the era.