This is a scarce example of a "U.S." marked and inspected 1860 First Model Richards Cartridge Conversion Revolver. These revolvers were converted by shaving the recoil shield 3/16 of an inch and installing a Richards breech plate with integral notch sight and loading gate. The recoil shield was machined to provide a straight channel for the loading and ejecting of cartridges. Secondly, it called for a rebounding firing pin which in turn forced the hammer to be ground flat in order to strike it properly. The barrel then had to be machined to accept the Richards ejector assembly/loading lever channel filler that is secured with a screw on the left side of the barrel lug. The top of the barrel is marked with the one-line address, and the rebated cylinder has the standard roll-engraved Texas Navy battle scene. The left side of the frame is marked "COLTS/PATENT". The left side of the barrel is marked "US" and inspector Ainsworth marked "A". The trigger guard and cylinder also have the Ainsworth "A" marking. U.S. Richards conversion revolvers are commonly found with mismatched numbers, and this revolver is no exception. Several of the major components have been renumbered to "156," including the frame. The cylinder is marked with the number "256," possibly a factory error. "156" is also marked on the ejector rod housing, loading gate and breech plate. The revolver is fitted with an unmarked, smooth, one-piece walnut grip. The leather holster appears to have be manufactured by J. Davy & Co. (faint marking on flap). The holster matches other "Military Belt Holsters" from the 1860s and 1870s pictured in "Packing Iron: Gun Leather of the Frontier West", including the example on page 21.