This is a very rare example of a Colt Model 1851 Navy revolver with factory Thuer conversion. The revolver has the Colt high polish commercial blue finish on the barrel, cylinder and grip straps; casehardened loading lever, frame and hammer; and one-piece varnished walnut grip. The revolver has the distinctive features of factory Thuer conversion revolvers which include: groove cut for loading cartridges on the right side of the frame, circular metal insert on the hammer face and threaded rammer end. The Thuer conversion ring is stamped "PAT SEP/15. 1868" on the side and has a hand-engraved, script "E" on the ejector flat. The conversion ring and the cylinder are numbered "166". The top barrel flat is marked "-ADDRESS COL. SAML COLT NEW-YORK U.S. AMERICA-." British "Crown G/P" and "CROWN V" proof and inspection marks are stamped on the left side of the barrel lug and on the cylinder (alternating between the chambers). The cylinder is roll engraved with the naval battle scene and "COLTS PAT. NO." but is not stamped with the revolver serial number. The left side of the frame is stamped "COLTS/PATENT." "36 CAL" is stamped on the left side of the trigger guard at the junction of the grip and frame. The full serial number "185322" along with the letter "L" is stamped on the bottom of the barrel lug, the frame, the trigger guard and the back strap. The loading lever (338) and barrel wedge (85074) are mismatched. Thuer Conversion revolvers were the first Colt metallic cartridge revolving firearms. Original examples in high condition are scarce. Comes with a brown leather open top flap holster.