This is a fine example of a U.S. Colt Second Model Dragoon revolver that was manufactured in 1851 as part of an Ordnance Department contract for Dragoon Model revolvers. This revolver has the distinctive combination of square back trigger guard and cylinder with rectangular stop slots found only on Second Model Dragoon revolvers. The cylinder has the six locking pins which were first utilized on Second Dragoon revolvers. The part-round/part-octagon barrel and the cylinder have a dull military blue finish while the loading lever, frame and hammer are color casehardened. The trigger guard and back strap are brass and the one-piece walnut grip is oil finished. The left side of the frame is roll-stamped: "COLT'S/PATENT/U.S." in three-lines. The top barrel flat is roll-stamped: "-ADDRESS SAML COLT NEW-YORK CITY-" in one line reading toward the breech. The cylinder is roll-stamped with the Ranger and Indian fight scene and "MODEL U.S.M.R./COLT'S PATENT" above and below the serial number. The full serial number, "10065", is stamped on the loading lever, barrel lug, frame, trigger guard, cylinder and back strap. All of the visible serial numbers match. Small "H" Ordnance sub-inspection marks are stamped on the barrel lug, frame, cylinder, trigger guard, back strap and left grip heel. The lower left side of the grip is stamped with a script "JH" sub-inspection mark in a rectangle with rounded ends. The lower right side of the grip is stamped with a script "WAT" final inspection mark with an oval border. Colt manufactured approximately 2,700 Second Model Dragoon revolvers in 1850-51 of which about 1,000 were U.S. contract revolvers. The Second Model Dragoon revolvers were manufactured in the smallest quantities of the Colt Dragoon series.