ATLAS
COLLECTIBLE FIREARMS

Atlas Collectible Firearms is profoundly honored to present an absolute holy grail of martial arms development: a legendary, documented WWII 1943 Union Switch & Signal 1911A1 Experimental Prototype. Chambered in the powerful .45 ACP with a 5-inch barrel, this ultra-rare toolroom developmental pistol bears the hand-stamped serial number EXP No 64. According to Charles Clawson’s definitive text on military 1911A1 pistols, it is estimated that only roughly 100 of these pre-production experimental examples were ever crafted in Swissvale, Pennsylvania, prior to standard wartime manufacturing. This elevates it to an elite tier of historical rarity, rivaling the mythical Singer contracts as a pinnacle investment-grade military heirloom.
As a genuine pre-production developmental piece, this toolroom frame correctly lacks the standard wartime final factory "P" proof marks and RCD military inspection stamps. The frame and slide feature distinct hand-stamped US&S factory logotypes alongside its unique experimental serial prefix. This historic survivor comes configured with an original short-stamped trigger, a sharp narrow checkered hammer, a checkered slide stop, a checkered safety latch, and a classic arched mainspring housing. The metal surfaces have been elegantly treated to a factory-refurbished high-polished blue finish, and the pistol carries its period-correct Keyes fiber checkered plastic stocks, featuring the authentic mismatched reinforcement ring variations between the left and right panels.
Residing inside an impressive custom deluxe wooden presentation display case lined in deep red velvet, this museum-grade prototype is primed for center-stage exhibition. Mechanically excellent with a smooth action, it retains a crisp, historical "HS" marked High Standard contract barrel. The polished blued finish remains remarkably clean, displaying only minor pinpoint areas of light superficial storage corrosion on the left side of the slide and near the magwell base, along with a replacement magazine. This is a monumentally significant, once-in-a-lifetime opportunity to secure an exceptional piece of American industrial wartime engineering that very few collectors will ever see in person.