This is a late WWI/post war frame that was manufactured by the Colt factory without any serial number, strictly as a replacement frame for pistols that were deemed unserviceable during depot/armory overhaul. In the post WWI years, and up to approximately 1950, these no-number frame were periodically pulled from storage and stamped with a "X" prefix serial number as replacements. This block of X-prefix serial numbers was applied by Springfield Armory to Model 1911 pistols as replacement frames. This specific frame still retains the black army style finish and has been assembled with an all blued, block style marked Model 1911 slide. The left side of the slide has the standard two line patent and address markings with the Rampant Colt logo in the middle with "MODEL OF 1911.U.S.ARMY" on the right side. The right side of the frame is marked "UNITED STATES PROPERTY" with the "X2863" serial number directly below that, with no other inspection or acceptance proofs. It has the standard WWI style blue parts and components and a Springfield Armory barrel that is marked with a "S and P" proof on the left side of the lug. It is fitted with standard WWI checkered diamond walnut grips and is complete with a half-tone WWI type magazine.