Nice example of the 1st Model M1851 Black Navy Navy Colt, Martial, US Revolver which came out of factory in 1853 & was, in 1870s, converted to a cartridge revolver for the US Navy by the Colt factory. This is the Richard Mason style conversion & was converted to .38 cal. This revolver was definetly converted by the Colt factory as it has the 2 Patent stamps over the Colt Patent & US on the left side of the revolver. Also the loading gate has the original serial no. stamping. Serial no. 61776 is all matching on the frame, barrel, cylinder, trigger guard, backstrap, loading gate & cylinder rod. This revolver has a 4 1/4" barrel with matching extractor rod & assembly. Butt of revolver has the first model markings of U*S*N still intact. Barrel has the New York City  Colt address Wood grips are the originals as they of the dark color the black navies were supplied with. Action is good. This revolver came with an old belt rig & holster that fits the revolver perfectly. There are 7 original .38 shells still in the belt loops. They are dirty & I haven't cleaned them. This revolver probably ended up going west after military use. You don't see many of these Black Navy conversions out there.