Manufactured circa 1873. This early production revolver was manufactured by Colt using unfinished and/or unassembled parts. This early pattern revolver lacks the external loading gate spring and two-line Richard's patent dates on the frame which were features of later production Richards-Mason Model 1851 conversion revolvers. The barrel is a partially completed percussion barrel. The revolver has the modified percussion cylinder with Richards-Mason breech plate, loading gate with internal spring, modified hammer with rimfire firing pin, ejector assembly secured by a screw on the left side of the barrel lug and ejector rod head with concentric rings on the face. The left side of the frame has the early "COLT'S/PATENT" marking. "36 CAL" is stamped on the left side of the trigger guard. The cylinder has the standard Colt Navy naval battle scene and "COLTS PATENT No." The top barrel flat has "-ADDRESS COL. SAML. COLT NEW-YORK U.S. AMERICA-." The inside of the loading gate is stamped with the assembly number "1317". The barrel lug, frame, trigger guard, back strap and cylinder are stamped with the serial number "597". The revolver is accompanied by a detailed description by previous owner John H. Thillmann. The description concludes: "This exceptional finished gun is in my opinion one of the top two Colt Model 1851 Navy conversions in condition". This revolver is illustrated on page 224 of "A STUDY OF COLT CONVERSION REVOLVERS" by Bruce McDowell.

Excellent. 95% plus of the bright original high polish blue finish is on the barrel and ejector housing. Finish wear is limited to some flaking on the rear quarter of the ejector housing and a few shallow dents on the right side of the barrel lug below the wedge. The cylinder retains nearly all of the naval scene and 90% of the high polish blue finish with some wear on the front. The frame, breech ring, hammer and loading gate have nearly 98% of the casehardened finish with strong case colors. The firing pin, frame screws and trigger retain close to 95% of the fire blue finish. Traces of the silver plating is present on protected areas of the trigger guard and back strap; the balance of the exposed brass on these components has aged to a mellow, untouched patina. The grip is excellent with 98% of the original piano finish remaining. The action functions perfectly. This is almost certainly one of the very best Colt Richards-Mason Model 1851 Navy Conversion revolvers extant.