Originally designed by Carl Swebilius of High Standard, the M42 was intended as a competitor for the Thompson SMG in police and military contract sales. One of the last generation of "heavy metal" SMGs, the M42 used machined steel and polished wood much like the Thompson, though with a more streamlined design with easier takedown. Unable to commit to the design due to a massive U.S. order for M2 machine guns, High Standard sold the design to the United Defense Supply Corporation, a private outfit established and run by then-members of the British Purchasing Commission, who went to Marlin for the actual act of manufacturing. Originally sought out by the Dutch, a large quantity of M42s were left in the warehouse when the Netherlands fell to the Nazis. The Office of Strategic Services and the U.S. Navy took interest in the surplus weapons, dropping them in occupied territories (which unfortunately included a large quantity captured in France by the Nazis and handed over to the Milice), funneling them to the Nationalist and Socialist Chinese, as well as arming their own agents. In clandestine work, the M42 was noted as being vulnerable to sand and mud and in need of diligent maintenance, but it was easier to clean and had a higher potential accuracy out to 100 yards. Fitted with a fixed blade front and windage/elevation adjustable rear sights, with a circled "P" stamped on the right side of the chamber, the three-line address and model markings on the left side of the lower receiver, and the three-position selector ("SEMI-AUTO", "->SAFE<-" and "AUTO") on the right side. Contoured front pistol grip and smooth buttstock, with a tan canvas sling and a checkered steel trapdoor buttplate. Included with the lot is one "double magazine" (a pair of magazines welded together, essentially a permanent "jungle" magazine) and five United Defense marked blued steel single magazines, as well as a modern case.

Very fine, with 70% of the original matte phosphate finish, showing areas of bright wear, scattered handling marks and a small amount of spotting. The wood is also very fine, with some dings and dents. 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.