The 120 mm Gun M1 was the
United States Army
The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...
's standard super-heavy
anti-aircraft gun
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, ...
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 opposin ...
and the
Korean War
, date = {{Ubl, 25 June 1950 – 27 July 1953 (''de facto'')({{Age in years, months, weeks and days, month1=6, day1=25, year1=1950, month2=7, day2=27, year2=1953), 25 June 1950 – present (''de jure'')({{Age in years, months, weeks a ...
, complementing the smaller and more mobile
M2 90 mm gun in service. Its maximum altitude was about , which earned it the nickname ''stratosphere gun''.
The M1 gun was used by the Army for air defense from 1944 to 1960. The 120 served primarily in static defensive roles, although it had been designed to be mobile. It became obsolete with the development of anti-aircraft missiles and was phased out after 1954.
History
The Army first worked on a 120 mm gun after the end of
World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, with a prototype being presented in 1924. The system was considered far too heavy and expensive to be useful, and the project slowed, although it was never canceled outright.
In 1938, the Army reviewed its needs for newer AA systems and decided to order new systems for both the heavy and super-heavy role. The former was filled by the new
M1 90 mm gun, which replaced the earlier
M3 3-inch gun then in use. For the super-heavy role, the 120 mm gun design was dusted off and mated to a new eight-wheel carriage, designated 4.7-inch M1 when it was accepted in 1940.
Like the 90 mm, the M1 gun was typically operated in a battery of four guns, initially with an associated
searchlight
A searchlight (or spotlight) is an apparatus that combines an extremely bright source (traditionally a carbon arc lamp) with a mirrored parabolic reflector to project a powerful beam of light of approximately parallel rays in a particular direc ...
,
SCR-268 radar (replaced later by the much-improved
SCR-584
The SCR-584 (short for '' Set, Complete, Radio # 584'') was an automatic-tracking microwave radar developed by the MIT Radiation Laboratory during World War II. It was one of the most advanced ground-based radars of its era, and became one of the ...
),
M10 gun director, and M4
Gun Data Computer
The gun data computer was a series of artillery computers used by the U.S. Army for coastal artillery, field artillery and anti-aircraft artillery applications. In antiaircraft applications they were used in conjunction with a director.
Variati ...
that automatically laid the guns. The
M6 Tractor
The M6 High-Speed Tractor was an artillery tractor used by the US Army during World War II.
Manufactured by Allis-Chalmers, it was used to tow heavy artillery pieces, such as the 8-inch Gun M1 and 240 mm howitzer M1.
Its G-number was (G-184) ...
was used as the prime mover.
The M1 gun entered service late in
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 opposin ...
. One battalion of M1 guns, the 513th AAA Gun Battalion, was deployed in the Philippines in February 1945, but never fired on any hostile aircraft.
After World War II ended and the
Cold War
The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because the ...
with the
Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
began, M1 guns were deployed in many locations in the U.S. and Canada. To defend against long range Soviet
Tu-4
The Tupolev Tu-4 (russian: Туполев Ту-4; NATO reporting name: Bull) is a piston-engined Soviet strategic bomber that served the Soviet Air Force from the late 1940s to mid-1960s. It was reverse-engineered from the American Boeing B-29 ...
bomber attack, the
Army Anti-Aircraft Command
An army (from Old French ''armee'', itself derived from the Latin verb ''armāre'', meaning "to arm", and related to the Latin noun ''arma'', meaning "arms" or "weapons"), ground force or land force is a fighting force that fights primarily on ...
(ARAACOM) formed 44 active duty and 22
National Guard
National Guard is the name used by a wide variety of current and historical uniformed organizations in different countries. The original National Guard was formed during the French Revolution around a cadre of defectors from the French Guards.
Nat ...
battalions equipped with M1 guns, divided into seven brigades and 20 anti-aircraft artillery groups. Two Canadian anti-aircraft battalions were also equipped with M1 guns for the joint defense of the
Soo Locks
The Soo Locks (sometimes spelled Sault Locks but pronounced "soo") are a set of parallel locks, operated and maintained by the United States Army Corps of Engineers, Detroit District, that enable ships to travel between Lake Superior and the low ...
. These guns were guided by the long range
Lashup Radar Network
The Lashup Radar Network was a United States Cold War radar netting system for air defense surveillance which followed the post-World War II "five-station radar net" and preceded the "high Priority Permanent System". ROTOR was a similar expedient ...
equipped with
AN/CPS-5
The AN/FPS-20 was a widely used L band early warning and ground-controlled interception radar system employed by the United States Air Force Air Defense Command, the NORAD Pinetree Line in Canada, the USAF CONAD in the continental United States, a ...
. M1 guns were deployed for the protection of nuclear production facilities, major industrial centers, strategic air force bases, and select major population centers.
In 1954, the
MIM-3 Nike Ajax surface-to-air missile became operational with ARAACOM. It substantially outranged the M1 gun, rendering it obsolete. ARAACOM began retiring the M1 gun from active-duty units and then from National Guard units. Then in 1957, the Soviet Union introduced the
R7, its first
ICBM
An intercontinental ballistic missile (ICBM) is a ballistic missile with a range greater than , primarily designed for nuclear weapons delivery (delivering one or more thermonuclear warheads). Conventional, chemical, and biological weapons c ...
, and the M1 gun became practically useless. By January 1960, all remaining National Guard units with M1 guns were converted to Nike missiles or deactivated.
Comparable weapons
*
12.8 cm FlaK 40 - Nazi Germany
*
130 mm air defense gun KS-30 - Soviet Union 1950
*
QF 4.5-inch Mk I – V naval gun
The QF 4.5 inch gun has been the standard medium-calibre naval gun used by the Royal Navy as a medium-range weapon capable of use against surface, aircraft and shore bombardment targets since 1938. This article covers the early 45-calibre fam ...
- Britain 1938, see land use
*
Type 3 12 cm AA gun - Japan
See also
*
List of U.S. Army weapons by supply catalog designation
This is a historic (index) list of United States Army weapons and materiel, by their Standard Nomenclature List (SNL) group and individual designations — an alpha-numeric nomenclature system used in the United States Army Ordnance Corps Supply ...
(SNL D-32)
*
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.
Nav ...
*
Rangekeeper
Rangekeepers 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 ...
*
Gun Data Computer
The gun data computer was a series of artillery computers used by the U.S. Army for coastal artillery, field artillery and anti-aircraft artillery applications. In antiaircraft applications they were used in conjunction with a director.
Variati ...
*
Fire-control system
A fire-control system (FCS) is a number of components working together, usually a gun data computer, a director, and radar, which is designed to assist a ranged weapon system to target, track, and hit a target. It performs the same task as a ...
*
Kerrison Predictor
The Kerrison Predictor was one of the first fully automated anti-aircraft fire-control systems. It was used to automate the aiming of the British Army's Bofors 40 mm guns and provide accurate lead calculations through simple inputs on three main ...
References
* TM 9-2300 Standard Artillery and Fire Control Materiel dated 1944
* TM 9-380
* SNL D-32
External links
* https://www.youtube.com/watch?v=bCpI7MyB2U8 use of the gun in Alaskan national guard at 25:01 minutes
[1954 US Army; The Big Picture TV-252]
{{DEFAULTSORT:120 Mm M1 Gun
World War II anti-aircraft guns
Anti-aircraft guns of the United States
120 mm artillery
Military equipment introduced in the 1940s