120 mm M1 gun
Encyclopedia
The 120 mm Gun M1 was the United States Army
's standard super-heavy anti-aircraft gun, complementing the smaller and more mobile 90 mm M3 in service. Its maximum altitude was about 60000 ft (18,288 m), which garnered it the nickname the stratosphere gun. The 120 served primarily in U.S. defensive roles, although it had been designed to be mobile and saw some action during the Korean War
. The 120 was phased out quite quickly in the 1950s with the introduction of the first truly effective missile systems, notably the Nike Ajax.
, with a prototype being presented in 1924. The system was considered far too heavy and expensive to be useful, and the project slowed down, although it was never canceled outright.
In 1938 the Army started studying its needs for newer AAA systems, and decided to order new systems for both the heavy and super-heavy role. The former was filled by the new 90 mm gun, which replaced the earlier 3-inch gun
then in use, while work on the 120 was dusted off and mated to a new eight-wheel carriage to produce the 4.7-inch M1 when it was accepted in 1940.
Only a small number of 120s were built, about 550 in total. They were mostly used on fixed mounts at various points around the continental U.S., although about fifteen were shipped to the Canal Zone
to replace the semi-experimental 105 mm M3 gun that had filled this role. Four were sent, perhaps by mistake, to Northern Ireland
. No 120 was ever fired at an enemy aircraft. In 1944 the gun was renamed as the 120 mm Gun M1, as metric naming became the standard.
Like the 90 mm, the 120 was typically operated in a battery of four guns, initially with an associated searchlight
and SCR-268 radar, and later with the much-improved SCR-584 radar and M10 Director (Military)
, and M4 Gun Data Computer
that
automatically laid the guns as well. the M6 Tractor
was used as the prime mover.
Several batteries of 120mm guns were stationed around London in 1944 and 1945 to combat the V1 "Buzz Bomb".
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
's standard super-heavy anti-aircraft gun, complementing the smaller and more mobile 90 mm M3 in service. Its maximum altitude was about 60000 ft (18,288 m), which garnered it the nickname the stratosphere gun. The 120 served primarily in U.S. defensive roles, although it had been designed to be mobile and saw some action during the Korean War
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
. The 120 was phased out quite quickly in the 1950s with the introduction of the first truly effective missile systems, notably the Nike Ajax.
History
The Army had originally attempted to make a 120 mm design just after the end of World War IWorld War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
, with a prototype being presented in 1924. The system was considered far too heavy and expensive to be useful, and the project slowed down, although it was never canceled outright.
In 1938 the Army started studying its needs for newer AAA systems, and decided to order new systems for both the heavy and super-heavy role. The former was filled by the new 90 mm gun, which replaced the earlier 3-inch gun
3-inch M1918 gun
The 3-inch M1918 gun was a United States 3-inch anti-aircraft gun that entered service in 1918 and served until it was finally superseded by the 90 mm M3 gun just prior to the opening of World War II...
then in use, while work on the 120 was dusted off and mated to a new eight-wheel carriage to produce the 4.7-inch M1 when it was accepted in 1940.
Only a small number of 120s were built, about 550 in total. They were mostly used on fixed mounts at various points around the continental U.S., although about fifteen were shipped to the Canal Zone
Panama Canal Zone
The Panama Canal Zone was a unorganized U.S. territory located within the Republic of Panama, consisting of the Panama Canal and an area generally extending 5 miles on each side of the centerline, but excluding Panama City and Colón, which otherwise would have been partly within the limits of...
to replace the semi-experimental 105 mm M3 gun that had filled this role. Four were sent, perhaps by mistake, to Northern Ireland
Northern Ireland
Northern Ireland is one of the four countries of the United Kingdom. Situated in the north-east of the island of Ireland, it shares a border with the Republic of Ireland to the south and west...
. No 120 was ever fired at an enemy aircraft. In 1944 the gun was renamed as the 120 mm Gun M1, as metric naming became the standard.
Like the 90 mm, the 120 was typically operated in a battery of four guns, initially with an associated searchlight
Searchlight
A searchlight is an apparatus that combines a bright light source with some form of curved reflector or other optics to project a powerful beam of light of approximately parallel rays in a particular direction, usually constructed so that it can be swiveled about.-Military use:The Royal Navy used...
and SCR-268 radar, and later with the much-improved SCR-584 radar and M10 Director (Military)
Director (military)
A director, also called an auxiliary predictor, is a mechanical or electronic computer that continuously calculates trigonometric firing solutions for use against a moving target, and transmits targeting data to direct the weapon firing crew....
, and M4 Gun Data Computer
Gun Data Computer
The gun data computer is a series of artillery computers used by the U.S. Army, for coastal artillery, field artillery, and antiaircraft artillery applications...
that
automatically laid the guns as well. the M6 Tractor
M6 Tractor
The M6 High-Speed Tractor was an artillery tractor used by the US Army in World War II to tow heavy artillery pieces such as 8 inch Gun M1 and 240 mm Howitzer M1.- See also :* List of U.S. military vehicles by supply catalog designation* List of U.S...
was used as the prime mover.
Several batteries of 120mm guns were stationed around London in 1944 and 1945 to combat the V1 "Buzz Bomb".
See also
- List of U.S. Army weapons by supply catalog designation (SNL D-32)
- Director (military)Director (military)A director, also called an auxiliary predictor, is a mechanical or electronic computer that continuously calculates trigonometric firing solutions for use against a moving target, and transmits targeting data to direct the weapon firing crew....
- RangekeeperRangekeeperRangekeepers were electromechanical fire control computers used primarily during the early part of the 20th century. They were sophisticated analog computers whose development reached its zenith following World War II, specifically the Computer Mk 47 in the Mk 68 Gun Fire Control system. During...
- Gun Data ComputerGun Data ComputerThe gun data computer is a series of artillery computers used by the U.S. Army, for coastal artillery, field artillery, and antiaircraft artillery applications...
- Fire-control systemFire-control systemA fire-control system is a number of components working together, usually a gun data computer, a director, and radar, which is designed to assist a weapon system in hitting its target. It performs the same task as a human gunner firing a weapon, but attempts to do so faster and more...
- Kerrison PredictorKerrison PredictorThe Kerrison Predictor was one of the first fully automated anti-aircraft fire-control systems. The predictor could aim a gun at an aircraft based on simple inputs like the observed speed and the angle to the target...