United Defense UD-42 (Model 42 / M42)

History

During and after World War II, countless different types of weapons were scattered on the market. Many are caused by the sheer necessity of war, driven by material rationing, basic supply and demand constraints, and economic/logistical measures.

After the Japanese attack on Pearl Harbor, the United States plunged into World War II in late 1941, and its war planners (and the local military-industrial complex) are now caught up in another global conflict for which they were ill-prepared.

This has led to a number of promising entrepreneurs and companies launching many new products in an attempt to secure this lucrative serial production deal. The United Defense Model 42 ("M42") is a compact submachine gun designed by Carl Swebilius as a possible replacement for the famous M1 Thompson submachine gun - an expensive, complex and high maintenance design of the last world war.

The same applies to the new weapon - in its prototype form. The 45 ACP cartridge is similar to the Thompson, with a wooden shoulder rest, machined metal frame and front vertical grip. The trigger unit is lowered in the usual way and the pistol grip is designed as part of the shoulder rest. The operation consists of a simple recoil operation and provides the operator with the ability to quickly reload, welding together 20-round magazine cases along its length as a collective unit - providing up to 40 rounds "ready".

Aiming is via a fixed front post and rear adjustable assembly.

The overall weight is 10 lbs, the overall length is 32 inches, and the barrel is 11 inches. The Select Fire feature allows control over the use of ammunition, while the rate of fire reaches 700 rounds per minute and the muzzle velocity is 1,100 feet per second.

As a short to medium range blocker, the M42 could prove to be an effective weapon of war.

The end result seems to fit the bill - the M42 looks good, and with a simpler approach, would be a good replacement for the more expensive M1 Thompson range. In its final form, it was redesigned as the ubiquitous German 9x19mm Parabellum pistol cartridge, readily available around the world, and allowed the operator to use any captured enemy ammunition stockpile.

In practice, this weapon was far from successful for the U.S. Armed Forces and was not used for future standardization. It turns out that the design is no easier to manufacture on a large scale than Thompson, as it still requires a lot of machining to come to fruition.

On the battlefield, the weapon is known for its tendency to accumulate dust, dirt and various other common battlefield debris - which in turn requires a rigorous maintenance schedule to keep the weapon in working condition. There were also issues with the different magazine assemblies, they tended to warp over a long period of time and stuck the gun on the feed mechanism at the worst possible moment.

As a result, the M1 Thompson remained in U.S. service for several days longer, while the M42 was handed over to Special Forces for the remainder of the war. Between 1942 and 1943, United Defense Supply eventually built around 15,000 prototypes.

This weapon ended up in the hands of resistance elements in China, Crete, Czechoslovakia, France, Italy, the Netherlands and the Philippines, where it was used as a viable weapon in combat conditions. The Office of Strategic Services (OSS)the precursor to the modern U.S.

Central Intelligence Agency (CIA)was also a high-level recipient of this line of weapons and was accustomed to conducting various covert operations throughout the war. After the conflict, many foreign operators' inventories remained in use - and extended their useful lives in the Cold War years that followed.

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