The United Defense M42 was a blow-back operated submachine gun produced by the United States during World War II for agents of the Office of Strategic Services.


With obvious resemblances to the M1928 Thompson, which was the gun the M42 was supposed to replace, the M42 weighed around 4.1 kilograms and was fitted with an 27.9 cm barrel.

The total length of the M42 was 82 cm and the effective range was around 150 meters.[1] The M42 could be chambered in either 9 x 19 mm Parabellum, .30 Carbine, or .45 ACP. Although, the 9 mm version was the most produced while the .45 ACP version was the least produced.[2] It had the ability to fire up to 700 rounds per minute and the muzzle velocity could reach in excess of 335.2 meters per second.

It was fed by a 20-round magazine and the magazine was often welded to another magazine to increase reload speed. The rear iron sights were adjustable for wind while the front iron sights were solid, post-type sights. The M42 was prone to jamming if it was not properly cleaned. Like the Thompson SMG, it was not made used stamped parts and was even more complicated to make.


United Defence M42

An M42.

The United Defense M42 was produced from 1942 to 1943 and having only been produced for a year, only 15,000 were ever manufactured. It was manufactured by the United Defense Supply Corporation. The UD M42 was also air-dropped to resistance groups throughout Europe.[2] After the introduction of the M3 "Grease Gun", however, the M42 was listed as substitute standard by the US military. The M42 actually served partisan forces more and better than it did US forces.


  2. 2.0 2.1

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