The M45 Quadmount (nicknamed the "meat chopper" and "Krautmower"Rottman, Gordon L.,
Browning .50-Caliber Machine Guns
', Osprey Publishing (2010), , p. 19-20 for its high rate of fire) was a weapon mounting consisting of four of the "HB", or "heavy barrel"

.50 caliber This is a list of firearm cartridges which have bullets in the to caliber range. *''Length'' refers to the cartridge case Case or CASE may refer to: Containers * Case (goods), a package of related merchandise * Cartridge case or casing, a ...

M2 Browning machine guns (of the M2 Turret Type (TT) variant) mounted in pairs on each side of an open, electrically powered turret. It was developed by the W. L. Maxson Corporation to replace the earlier M33 twin mount (also from Maxson). Although designed as an

anti-aircraft weapon Anti-aircraft warfare, counter-air or air defence forces is the battlespace response to aerial warfare, defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action".AAP-6 It includes surface based, ...

, it was also used against ground targets. Introduced in 1943 during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

, it remained in US service as late as the

Vietnam War The Vietnam War (also known by other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vietnam a ...

History

In order to develop a mobile anti-aircraft weapon, several 0.5 inch (12.7 mm) twin machine gun mounts were tested on the chassis of the M2 half-track including Bendix, Martin Aircraft Company, and Maxson. The Maxson M33 turret mount was preferred and—on the larger M3 half-track (T1E2)—was accepted for service in 1942 as the M13 Multiple Gun Motor Carriage. The mount was also used on the similar M5 half track as the M14 Multiple Gun Motor Carriage.Green (2000), p. 150. Experimentally, the Quadmount was also tested in 1942 on a M3 Light Tank in place of the tank's turret but the project was terminated. Even as production of the two MGMC vehicles was underway, there was work to increase the firepower. Re-working the M33 to take four machine guns produced the M45 mounting. The M45 Quadmount was the principal weapon (along with the 37mm gun) of highly mobile anti-aircraft artillery battalions deployed in the

European Theater The European theatre of World War II was one of the two main theatres of combat during World War II. It saw heavy fighting across Europe for almost six years, starting with Germany's invasion of Poland on 1 September 1939 and ending with the ...

during World War II. These battalions provided invaluable air defense to much larger units, particularly field artillery. The M45 Quadmount units served as a very strong deterrent to

strafing Strafing is the military practice of attacking ground targets from low-flying aircraft using aircraft-mounted automatic weapons. Less commonly, the term is used by extension to describe high-speed firing runs by any land or naval craft such ...

runs by enemy warplanes as, in addition to their gross firepower, its quartet of Browning M2HB "heavy barrel" .50 caliber guns were capable of being "tuned" to converge upon a single point at distances which could be reset while in use. Multiple-gun mounts were developed for the M2 Browning because the M2's rate of fire (450–550 rounds per minute) for a single gun was too low for anti-aircraft use. The M45 found use throughout the war as a land-based weapon, particularly during the

Battle of the Bulge The Battle of the Bulge, also known as the Ardennes Offensive, was the last major German offensive campaign on the Western Front during World War II. The battle lasted from 16 December 1944 to 28 January 1945, towards the end of the war in ...

. Although the Allies achieved

air supremacy Aerial supremacy (also air superiority) is the degree to which a side in a conflict holds control of air power over opposing forces. There are levels of control of the air in aerial warfare. Control of the air is the aerial equivalent of comm ...

by the invasion of Normandy in June 1944, German attack runs were still a threat. German ''Jabo'' fighter-bombers could approach and attack at low altitude and then quickly retreat to avoid Allied fighters. The

Luftwaffe The ''Luftwaffe'' () was the aerial-warfare branch of the German ''Wehrmacht'' before and during World War II. Germany's military air arms during World War I, the ''Luftstreitkräfte'' of the Imperial Army and the '' Marine-Fliegerabtei ...

also mustered a large number of planes for

Operation Bodenplatte Operation Bodenplatte (; "Baseplate"), launched on 1 January 1945, was an attempt by the Luftwaffe to cripple Allied air forces in the Low Countries during the Second World War. The goal of ''Bodenplatte'' was to gain air superiority during th ...

that took place on New Year's Day 1945. On March 7, 1945 when the U.S. Army discovered the

Ludendorff Bridge The Ludendorff Bridge (sometimes referred to as the Bridge at Remagen) was in early March 1945 a critical remaining bridge across the river Rhine in Germany when it was captured during the Battle of Remagen by United States Army forces durin ...

intact across the Rhine, M45-armed U.S. half-tracks defended the American troops crossing the bridge on March 9, 1945 to great effect. At Oppenheim, when the Allies were gathering to make a massive push after crossing the river Rhine (March 1945), 248 German warplanes were used in an effort to destroy the bridge first. U.S. Army anti-aircraft artillery battalions massed, shot down 30% of the attacking force mainly with M45 Quadmounts and prevented the bridge from being touched before the

U.S. Third Army The United States Army Central, formerly the Third United States Army, commonly referred to as the Third Army and as ARCENT, is a military formation of the United States Army which saw service in World War I and World War II, in the 1991 Gulf Wa ...

went into Germany. It was also tested by the US Navy as a solution for the

Kamikaze , officially , were a part of the Japanese Special Attack Units of military aviators who flew suicide attacks for the Empire of Japan against Allied naval vessels in the closing stages of the Pacific campaign of World War II, intending t ...

attacks that started in late 1944. Two Essex class aircraft carriers received six mounts each for operational testing starting with CV-16 Lexington in May 1945. Her gunnery department in general was positive towards the powered mounts but felt that the guns were too light and ineffective against the high speeds that the diving Kamikaze aircraft possessed. The M45 Quadmount was ineffective against the new, fast-flying planes of the

Jet Age The Jet Age is a period in the history of aviation defined by the advent of aircraft powered by jet turbine engines, and by the social change this brought about. Jet airliners were able to fly much higher, faster, and farther than older pisto ...

. However, it was used against infantry targets in US post-war service. In Vietnam they were pressed into service to defend bases and to ride escort convoys along Viet Cong roads. The

French Army The French Army, officially known as the Land Army (french: Armée de Terre, ), is the land-based and largest component of the French Armed Forces. It is responsible to the Government of France, along with the other components of the Armed Force ...

also used M45s in combat. M45 Quad Mounts were placed in trucks to deal with ambushes and four M45s were used during the Battle of Dien Bien Phu.

TCM-20

The TCM-20 was a postwar Israeli development of the M45 mount, equipped with two 20mm

Hispano-Suiza HS.404 The HS.404 is an autocannon originally designed and produced by Spanish/French company Hispano-Suiza in the mid-1930s. It was widely used as an aircraft, naval and land-based weapon by French, British, American and other military services, par ...

cannons in lieu of machine guns. In frontline Israeli service, it was replaced by the M163 Vulcan Air Defense System in the 1970s, but some reserve units still used TCM-20s into the 1980s. The weapon was also exported to several third-world countries.

Mountings

During World War II, the M45 turret was mounted on two specific systems; the M16 Multiple Gun Motor Carriage and the M51 Multiple Machine Gun Carriage. When mounted on the M20 trailer, it was known as the M55 Machine Gun Trailer Mount, but this system had not finished testing before the cessation of hostilities. M51s were withdrawn from service by the end of World War II in favor of the M55. During the Korean War, the M55 and M16 saw extensive combat, and lessons learned in Korea led to the conversion of an additional 1200 M3 halftracks into the M16A1 variant by adding an M45 turret. These can be identified by the lack of fold-down armor and rear troop door on the crew compartment and were often fitted with the roller front bumper instead of the winch bumper fitted to all M16s. In 1954 an additional modification was made to roughly 700 M16 MGMCs, adding the rear troop door and bolting the fold-down armor in the up position. This modification became known as the M16A2 MGMC. The M55 received a new, more powerful generator in the 1960s and served through the Vietnam War, usually mounted in the back of an M35 2.5 ton or M54 5-ton

gun truck A gun truck is an armored vehicle with one or more crew-served weapons, typically based on a commercial vehicle. Gun trucks often have improvised vehicle armor, such as scrap metal, concrete, gravel, or sandbags, which is added to a heavy truck ...

Operation

The M45 is operated by two loaders and one gunner. The mount is capable of traversing a full 360 degrees around, with an angle elevation between -10 and +90 degrees. Traverse and elevation are electrically driven, powered by two rechargeable 6-volt batteries. All four guns could be fired at once, but standard practice was to alternate between firing the upper and lower pair of guns, allowing one pair to cool while the other was in use. This allowed for longer periods of action as overheating of the gun barrels was lessened. The "tombstone" model M2 ammunition chests held 200 rounds each—with one ammunition chest on an M45 system holding ten times as many rounds as each of the four twenty-round 20mm magazines of the German ''Flakvierling'' system held (and which, on the German ordnance system, had to be changed every six seconds on each gun of the quartet to ensure its own top 800 rpm "combined" firing rate), with each M2 ammo chest weighing 89 pounds each when full.

Gallery

File:G-508 GMC CCKW-353-B2 with m55 Machine-gun mount pic3.JPG, CCKW-353-B2

with M45 on M20 trailer in bed. This configuration did not see combat in World War II as it was still in testing by the cessation of hostilities File:TCM-20-hatzerim-2.jpg, Israeli TCM-20,

Israeli Air Force Museum The Israeli Air Force Museum is located at Hatzerim Airbase in the Negev desert. The museum was established in 1977 and has been open to the public since 1991. The museum displays a variety of Israeli Air Force and foreign aircraft, as well as a ...

, equipped with a pair of 20mm

cannon Image:M20 trailer mount.jpg, M20 trailer mount, 1947 Image:M17 trailer mount.jpg, M17 trailer mount, 1947 Image:G-102 White M16A1 Half-Track MGMC pic2.JPG, M16 MGMC File:Quad 0.50 used for convoy security along Route 9.jpg, Quadmount used for convoy security along Route 9, Vietnam 1968 File:Pakistani Army Soldiers on an M45 Quadmount in 1965.jpg, Pakistani soldiers operating a M45 Quadmount during the 1965 conflict with India File:Lookout Mountain Laboratory photographer on camera mount.jpg, Photographer on an M45 repurposed as camera mount at

Lookout Mountain Air Force Station Lookout Mountain Air Force Station (LMAFS) is a Formerly Used Defense Site which today is a private residence of actor Jared Leto in the Laurel Canyon neighborhood of Los Angeles, California. The USAF military installation produced motion pictures ...

Operators

* *

Notes

References

Training Manuals * TM 9-2800 Military vehicles * TM 9-2010 * TM 9-1223 * FM 44-57 M20 trailer * SNL G220 * TM 9-789 M17 trailer * SNL G221
TM 9-881

External links

Scribd's Archived M45 Quadmount Manual

{{Webarchive, url=https://web.archive.org/web/20081222001357/http://www.skylighters.org/quad50/index.html , date=2008-12-22

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