This unique variation of the Colt New Service revolver is number 37 of only 50 known to have been manufactured using leftover frames from the Colt U.S.M.C. Model of 1909 contract. These frames feature a narrower rounded butt, with the "U.S.M.C./No." markings. These leftover frames were marked with a square and a number between 1 and 50 inside the crane well. The extra frames were manufactured to account for anticipated losses, sales to individuals, and because at the time Colt felt it would be easier to have a few on hand as opposed to having to retool should the need for more arise. The butt was numbered to match the crane when the frame was assembled into a complete gun. With a fixed blade front and frame notch rear sights, "UNITED STATES PROPERTY" marking on the underside of the barrel and the early "Rampant Colt/C" marking on the side plate. The grips are checkered walnut, and the butt is fitted with a lanyard loop. The included factory letter confirms the serial number, barrel length, finish, and date of shipment as November 6, 1918, to the commanding officer at Camp Bowie in Fort Worth, Texas. Author Timothy J. Mullin devotes two sections of his book "Colt's New Service Revolver: A Particular Strong, Heavy Weapon" to this scarce variation.

Very good as rebarreled with 70% of the factory blue finish remaining, showing areas of high point and edge wear, small scratches throughout, small dings, slight marring of the screw heads, and compression marks at the frame/barrel junction. The heavily worn grips are fair with areas of smoothed checkering, small indentations and general handling marks. Mechanically excellent.