This is an original, WWII US Army contract Model 1911A1 "Service Model" Ace pistol chambered in 22LR. These were originally produced as a low-cost method to train troops that duplicated the weight, feel and function of the original Model 1911A1 pistol. This model used the new "Floating Chamber" designed by "Carbine Williams" that readily made the pistol fire exactly like the Model 1911A1. The serial number of this pistol places the shipment in mid-1945. It has the two line Colt address and patent dates on the left side of the slide with the Rampant Colt logo at the end of the markings, with the right side marked, "COLT/SERVICE MODEL/<ACE>/ .22LR". The right of the frame has the "G.H.D." inspected stamp for Col Guy Drewey with the Colt "R" and "VP" inside a triangle proof on the trigger guard bow. The right side of the frame has the "73" on the trigger guard, and "UNTIED STATES PROPERTY" over the serial number "SM5336". It has the desirable adjustable rear sight with target height front sight. It is fitted with a narrow checkered hammer, stamped trigger, arched serrated mainspring housing and reinforced Colt wood grips.