This is an original brass bullet mold marked "Colt's Patent" on the top. Caliber is .31 with 2 cavities for the ball and conical bullets. This is an earlier type (circa 1850-53) without the iron sprue cutter...which debuted around 1854. According to Robin Rapley's excellent book titled "Colt Accoutrements 1834-1911", P. 124 M#17, he identifies this one as the Mold for the 1849 Colt Pocket Revolver with two small improvements over the 1848 Baby Dragoon mold....mainly a slightly larger funnel on the top of the block and the addition of a "heal (grease groove)" for the conical bullet cavity. This grease groove helped "facilitate loading into the cylinder chamber".
Overall condition is Very Good with good markings and nice straight brass. One of the great things about brass is it won't rust like an iron mold, but being made of softer metal, were highly prone to damage. This one has nice straight handles and no play or looseness at the hinge. Cavities are a little dirty but excellent (no dings or damage) and even though its approaching its 160th Birthday, remains perfectly capable of producing nice sharp castings. The block is also very straight showing just a few minor tap marks. Overall, has a nice mellow patina. Would make a great accessory for an early Colt Model 1849 Pocket revolver.