Only a small number of these pistols were converted to this system around the late 1850s to early 1860s. The conversion consists of fitting a drum bolster and nipple to the barrel, removing the frizzen and flash pan, and replacing the cock with a hammer with a built in automatic priming system. The design was patented by George W.B. Gedney of New York. Only a small number of these components were purchased by the U.S. government. The hammer is marked "PAT. MARCH 15. 1859" towards the top and then "AMc PRIMING & ARMS Co./NEW-YORK" on the neck. The lock has the original "WATERS/MILBURY. MS./1838" marking along with an "E" stamp. The barrel has "U.S./JH/P" and "H" on the left at the breech. The stock has traces of two cartouches on the left.

Good with gray patina, partially polished mild pitting, and general mild overall wear. The lightly sanded and re-oiled stock is also good and has traces of the cartouches, a thing crack on the left flat, and a few dings. Mechanically fine.