They're unique guns that were originally made from 1871-3 and were the predeccesor to the 1873 SAA. They were the only cartridge revolver Colt made with a roll mark cylinder. They were offered with both army and navy grips only in 7.5 inch barrels chambered in 44CF (the very first were rimfire). They had a unique rear sight on the back of the barrel which prevented them from shooting a foot high like the conversions of the time. They shoot very well with black powder due to their large gas ring which keeps fouwling out of the arbor and locking up the gun. The army tested and rejected them which some say resulted in the 1873 SAA. I have 3 from Cimarron and adore them, I can highly recomend you try one.