The Colt Model 1851 Navy Revolver was introduced in 1850 and manufactured through to 1873. As many as 215,348 of this model were produced at the Hartford factory in Connecticut with serial numbers beginning at serial number I through to 215348 which is the highest number known. The Navy was a scaled up version of the Pocket in the larger .36 caliber, with six-shot cylinder and a 7½ inch octagonal barrel with attached loading lever. The barrel and cylinder were blued with a casehardened frame, hammer and loading lever. The brass back-strap and trigger-guard were silver-plated and the grips were one-piece varnished walnut. The left side of the frame throughout the production marked ‘COLTS/PATENT’. The roll engraved cylinder scene depicts the battle between the Texas Navy and that of Mexico.

The three main barrel addresses found on Colt Model 1851 revolvers are ‘ADDRESS SAML COLT NEW-YORK CITY’, ‘ ADDRESS SAM'L COLT. HARTFORD CT’ and ‘ADDRESS COL. SAML COLT NEW-YORK U,S. AMERICA’. There are also barrels marked ‘- ADDRESS COL. COLT LONDON –‘ . These revolvers were made up in Hartford from parts that were shipped back to America after the London factory closed. Some were exported back to England and will be found with British proof-marks in a higher serial range that the London production and others were sold in the U.S. with no proofs. There are many variations in materials, markings, back-strap & trigger-guards, frames, grips etc. Some are cut for all three models of attachable shoulder-stock. On engraved and special order Navies the frame was normally hand-engraved ‘COLT’S PATENT’ on the left side. There were a variety of finishes available including silver-plating and gold-plated or a combination of both. Grips came in several types of wood including select burl walnut or ivory.

There were military contracts to the Army and the Navy. These revolvers are usually found with a U.S. stamped on the left side of the frame below ‘COLTS/PATENT’ and government inspector marks on the grips and on various metal parts on the revolver.

The 51 Navy comes in four variant models with some over-lapping of the different models.

First Model: Serial range 1 to 800 with square-back brass trigger-guard and wedge screw entering the barrel lug under the wedge.

Second Model: Serial range 800 to 4200 with square-back brass trigger-guard and wedge screw entering the barrel lug above the wedge. A few are found in serial ranges up to 4500.

Third Model: Serial range 4200 to 85000 with small rounded brass trigger-guard. Some are found in a lower serial range than 4200.

Fourth Model: Serial range 85000 – 215348 with large rounded brass trigger guard.