A closed-bolt blowback-operated sub-machine gun, the Reising Model 50 saw action with the U.S. Marines in the Pacific as a substitute for the M1 Thompson, though they found their best success as defensive weapons for war-essential industries and as patrol carbines for American police forces. Blade front and elevation adjustable peep rear sights, with a flash hider/muzzle break, cooling fins on the barrel, three-line New Haven address near the ejector port, and three-position selector/safety on the right side. The right side of the receiver is also marked "USAPOP" in electric pencil. No information on this marking was supplied by the consignor, though research indicates that the "USAPOP" acronym was used by U.S. Army Port Operations, Pusan, which was first established during the Korean War as the 809th Port Command (Provisional) to manage the massive quantity of military shipping through the Port of Pusan, and operated under the USAPOP designation c.1967-1981. While the Reising was seen as too intricate for jungle warfare, it likely would have made a suitable weapon for port security. Smooth pistol grip stock with a cocking lever on the underside and a lightly ribbed buttplate. Magazine absent.

Very fine, with 85% of the original blue finish, showing scattered light spotting, heavier pitting on the buttplate, and scattered edge wear and handling marks. The stock is very good, with some light dents and scuffs. Mechanically excellent. NOTE: This item is restricted as a National Firearms Act (NFA), fully transferable Class 3, which is registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives, (BATFE) that is classified as a "Curios or Relic" as defined in 27 CFR, 478.11. These weapons are still subject to the provisions of 18 U.S.C. Chapter 44 and 27 CFR part 478.