United Defense M42
Encyclopedia
The United Defense M42 was an American
submachine gun
in World War II
. It was produced from 1942 to 1943 by United Defense Supply Corp. (a government-formed company specifically tasked with weapons development) for possible issue as a replacement for the Thompson submachine gun
and was used by agents of the Office of Strategic Services
(OSS).
, which the U.S. military considered both expensive and complicated to produce. Made in both 9x19mm Parabellum and .45 ACP prototypes, the 9 mm version was the only one to ever see widespread production. Manufactured by High Standard Firearms
and Marlin Firearms
, about 15,000 were produced in the last three years of World War II. Only six .45 ACP prototype test guns were made.
The weapon holds 25 9mm rounds in its magazine, and can fire them at 900 rounds per minute. Frequently two 25 round magazines were welded face-to-face allowing a quick reload when the first became empty (see illustration). The weapon itself weighs 10 lb (4.54 kg)(empty), with a length of 32.3 in (820 mm). The barrel length is 11 in (279 mm), and it has six-groove right-hand rifling
.
An extremely simple design, it was a straight blowback
, selective fire
weapon. It was built under "hurry-up" war conditions and some of its design flaws stem from this approach. Problems with the weapon were varied. Under combat conditions it was found that the sheet metal magazines had a tendency to warp out of shape causing feeding problems. They had little tolerance for exposure to large amounts of mud and sand and tended to jam if not cleaned regularly. The gun was also labor intensive to produce. It used all machined parts, no stampings, and under wartime conditions machine work is at a premium.
The M42 submachine gun was classified as a substitute standard when the M3 submachine gun
was introduced.
in occupied Europe. The weapon was air dropped to supply British-led partisan forces on the island of Crete
, where it was used extensively. It also saw use among the partisan forces of the Italian
and French Resistance
. Some of them were transferred to Dai Li
's regular resistance forces in China
for use against the Japanese invasion
. The use of the 9 mm caliber allowed resistance forces to use captured ammunition in their weapons, eliminating the need for repeated re-supply drops.
Overall the weapon failed in its intended role (to replace the Thompson) but proved effective in limited use in the hands of resistance forces.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
submachine gun
Submachine gun
A submachine gun is an automatic carbine, designed to fire pistol cartridges. It combines the automatic fire of a machine gun with the cartridge of a pistol. The submachine gun was invented during World War I , but the apex of its use was during World War II when millions of the weapon type were...
in World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. It was produced from 1942 to 1943 by United Defense Supply Corp. (a government-formed company specifically tasked with weapons development) for possible issue as a replacement for the Thompson submachine gun
Thompson submachine gun
The Thompson is an American submachine gun, invented by John T. Thompson in 1919, that became infamous during the Prohibition era. It was a common sight in the media of the time, being used by both law enforcement officers and criminals...
and was used by agents of the Office of Strategic Services
Office of Strategic Services
The Office of Strategic Services was a United States intelligence agency formed during World War II. It was the wartime intelligence agency, and it was a predecessor of the Central Intelligence Agency...
(OSS).
History
The M42 was developed by United Defense Supply Corp. specifically as a replacement for the Thompson submachine gunThompson submachine gun
The Thompson is an American submachine gun, invented by John T. Thompson in 1919, that became infamous during the Prohibition era. It was a common sight in the media of the time, being used by both law enforcement officers and criminals...
, which the U.S. military considered both expensive and complicated to produce. Made in both 9x19mm Parabellum and .45 ACP prototypes, the 9 mm version was the only one to ever see widespread production. Manufactured by High Standard Firearms
High Standard Manufacturing Company
High Standard Manufacturing Company Inc. is an American manufacturer of firearms, based in Houston, Texas. The company was originally founded in Hamden, Connecticut in 1926 as a supplier to the numerous firearms companies in the Connecticut Valley.-History:...
and Marlin Firearms
Marlin Firearms
Marlin Firearms Co., formerly of North Haven, Connecticut, is a manufacturer of high power, center fire, lever action, and .22 caliber rimfire rifles. In the past, the company made shotguns, derringers and revolvers...
, about 15,000 were produced in the last three years of World War II. Only six .45 ACP prototype test guns were made.
The weapon holds 25 9mm rounds in its magazine, and can fire them at 900 rounds per minute. Frequently two 25 round magazines were welded face-to-face allowing a quick reload when the first became empty (see illustration). The weapon itself weighs 10 lb (4.54 kg)(empty), with a length of 32.3 in (820 mm). The barrel length is 11 in (279 mm), and it has six-groove right-hand rifling
Rifling
Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis...
.
An extremely simple design, it was a straight blowback
Blowback (arms)
Blowback is a system of operation for self-loading firearms that obtains energy from the motion of the cartridge case as it is pushed to the rear by expanding gases created by the ignition of the propellant charge....
, selective fire
Selective fire
A selective fire firearm has at least one semi–automatic and one automatic mode, which is activated by means of a selector which varies depending on the weapon's design. Some selective fire weapons utilize burst fire mechanisms to limit the maximum or total number of shots fired automatically in...
weapon. It was built under "hurry-up" war conditions and some of its design flaws stem from this approach. Problems with the weapon were varied. Under combat conditions it was found that the sheet metal magazines had a tendency to warp out of shape causing feeding problems. They had little tolerance for exposure to large amounts of mud and sand and tended to jam if not cleaned regularly. The gun was also labor intensive to produce. It used all machined parts, no stampings, and under wartime conditions machine work is at a premium.
The M42 submachine gun was classified as a substitute standard when the M3 submachine gun
M3 submachine gun
The M3 was an American .45-caliber submachine gun adopted for U.S. Army service on 12 December 1942, as the United States Submachine Gun, Cal. .45, M3. The M3 was designed as a more cost-effective alternative to the Thompson, optimized for mass production...
was introduced.
Operational use
Intended for use by U.S. troops at the time of its design, it found more favor being air-dropped to partisan forcesResistance during World War II
Resistance movements during World War II occurred in every occupied country by a variety of means, ranging from non-cooperation, disinformation and propaganda to hiding crashed pilots and even to outright warfare and the recapturing of towns...
in occupied Europe. The weapon was air dropped to supply British-led partisan forces on the island of Crete
Crete
Crete is the largest and most populous of the Greek islands, the fifth largest island in the Mediterranean Sea, and one of the thirteen administrative regions of Greece. It forms a significant part of the economy and cultural heritage of Greece while retaining its own local cultural traits...
, where it was used extensively. It also saw use among the partisan forces of the Italian
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
and French Resistance
French Resistance
The French Resistance is the name used to denote the collection of French resistance movements that fought against the Nazi German occupation of France and against the collaborationist Vichy régime during World War II...
. Some of them were transferred to Dai Li
Dai Li
Major General Dai Li was born Dai Chunfeng with the courtesy name of Yunong in Baoan, Jiangshan, Zhejiang, China. He studied at the Whampoa Military Academy, where Chiang served as Chief Commandant, and later became head of Chiang's Military Intelligence Service.-Early life:At age four, his...
's regular resistance forces in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
for use against the Japanese invasion
Second Sino-Japanese War
The Second Sino-Japanese War was a military conflict fought primarily between the Republic of China and the Empire of Japan. From 1937 to 1941, China fought Japan with some economic help from Germany , the Soviet Union and the United States...
. The use of the 9 mm caliber allowed resistance forces to use captured ammunition in their weapons, eliminating the need for repeated re-supply drops.
Overall the weapon failed in its intended role (to replace the Thompson) but proved effective in limited use in the hands of resistance forces.