Starting on June 21, 1913, U.S. Military along with "Springfield Armory" and "Colt Patented Firearms Manufacturing Co." attempted to develop a .22-cal. rimfire pistol that could be used for training purposes. By 1927, the military became convinced that a pistol identical to standard "Service Pistol", but in .22-cal. rimfire was impractical and dropped the idea. In 1930 Colt purchased advertising that, in effect, requested the shooting public to let the company know if they would be interested in a .22 rimfire pistol built similar to "Government Model". The response must have been positive, because in 1931 Colt Ace appeared on the market. Ace uses a frame similar to the frame of "Government Model", with a highly modified slide and heavy barrel. Chambered for .22 LR cartridge only. Size is the same as larger-caliber version and weight is 36 oz. Operation is straight blowback. Ace has a 10-round detachable magazine and features "Improved Ace Adjustable Target Sight". Markings on left side of slide are the same as on "Government Model"; right side reads "Colt Ace 22 Long Rifle". The Army purchased a few pistols (totaling 206) through 1936. The Army concluded that the function of Ace was less than perfect, as they concluded the .22 rimfire lacked the power to consistently and reliably operate the slide. Approximately 11,000 Ace pistols were manufactured and in 1941 they were discontinued. Many owners today find that although ACE is somewhat selective to ammunition, with full power loads it is a highly reliable pistol that does not require the constant cleaning needed by the "Service Model Ace". NOTE: Add 33 percent for finish 99-100 percent.