The Colt Third Model Dragoon Revolver was manufactured from circa 1851 through to 1861. A total of about 10,500 were produced in this period in a serial range from about 10200 through to about 19600. Some early models overlapped with the Second Model. Serial numbers are found on all major parts.

The revolver is in .44 caliber, weighs 4 pounds and 2 ounces and has a 7½ inch part round and part octagonal barrel. Towards the end of the production some were produced with an 8 inch barrel. The main difference between a Second and Third Model Dragoon is the change from a square-back trigger-guard to a rounded version. It also has the flat design main-spring and the roller bearing where the hammer engages with the spring. The loading lever also used both the vertical and horizontal catch.

The barrel and cylinder were blued with casehardened frame, hammer and loading lever. The back-strap and square-back trigger-guard are of brass and silver-plated on commercial models and left plain on military contract revolvers. The six shot cylinder has rectangular cylinder stops with guide grooves and was roll engraved with the Texas Ranger and Comanche Indian fight scene. The revolver was furnished with one-piece walnut grips which were varnished for the commercial market and oil-stained for the military contracts. Military issue Third Model Dragoons have government inspector cartouches on the grips and letter stampings on various metal parts.

The barrel address reads from muzzle to breech either ‘-ADDRESS SAML COLT, NEW-YORK CITY-’ or ‘ADDRESS SAML COLT NEW-YORK CITY’ with bracket finials at either end. There is the normal ‘COLT’S/PATENT’ or ‘COLTS/PATENT stamping on the left side of the frame with ‘U.S.’ below on Government contract revolvers.

The cylinder also has a roll-engraved panel marking in large letters ‘COLT'S PATENT’ along with a second panel of ‘MODEL U.S.M.R.’ (U.S. Mounted Rifles) with the serial number stamped within. Some models have the rarer marking of ‘U.S. DRAGOONS’ instead of the U.S.M.R. markings. It is estimated that between 1,200 and 1,500 Third Models were cut to accept all of the three types of detachable shoulder stocks. The third pattern stock has a four screw frames, blued steel back-strap with a groove in the heel and a notched recoil shield. The barrel would have folding leaf sights.

Philip Boulton of Southampton, England has collated and recorded a survival rate of at least 7.82% of the original production of First, Second and Third Dragoon revolvers. For in-depth reference on Colt Dragoon revolvers see ‘The Book of Colt Firearms- 3rd Edition’ by R.L. Wilson.