Royal Ordnance L7
Encyclopedia
The Royal Ordnance L7 is the basic model of Britain's
most successful tank gun
. The L7 was a 105 mm L/52 rifled design intended for use in armoured fighting vehicle
s. It was so successful that it armed not only British post-war designs, but was used almost universally in "the West" as the main armament of almost every main battle tank
of the period.
The L7 was developed by Britain's Royal Ordnance Factories to equip British tanks of the postwar (Cold War
) period as the successor to the 20 pounder
(84 mm) used on Britain's postwar tank—the Centurion
.
The L7 was a popular weapon and it was maintained in use even after it was superseded by the L11 series 120 mm
rifled tank gun, for some Centurion tanks operating as Artillery Forward Observation and Armoured Vehicle, Royal Engineers
(AVRE
) vehicles. The L7, and adaptations of it, can be found today as standard or retrofitted equipment on a wide variety of tanks developed during the Cold War. It is also being used as the main armament of the U.S. Army
's Stryker
-based Mobile Gun System.
During the Hungarian Revolution of 1956, a Soviet T-54A medium tank was driven onto the grounds of the British embassy in Budapest by the Hungarians. After an examination of this tank's armour and 100 mm gun
, British officials decided that the 20 pounder
was apparently incapable of defeating it. Hence there was a need to adopt a 105 mm gun.
The L7 was specifically designed to fit into the turret mountings of the 20 pounder. This would enable the Centurions to be upgunned with minimum modifications, hence the fleet could be upgraded in a shorter time and at a lower cost.
The first tank to be equipped with the L7 was the Centurion Mark 5 in 1959. The gun was subsequently adopted by several other nations for their own MBT
s, most notably the German
Leopard 1 (for which the L7A3 variant was developed), the Japan
ese Type 74
(produced under license by Japan Steel Works
), the Swedish
Stridsvagn 103
(as the L74, with a longer barrel and automatic loader
), India
for its upgraded T-55
A, the US
M60 series
and earliest versions of the M1 Abrams
(with the M68), and the Israel
i Merkava
. In addition, several countries have used the gun to improve the firepower of existing main battle tanks. Derivatives have even been mounted in Warsaw Pact-built T-54 and T-55 tanks in Israel, Egypt and Iraq, and Type 79
tanks in China.
for loading the fixed cartridge
cases. The gun recoil
s approximately 29 cm (in most applications), automatically ejecting the empty cartridge case upon reaching full recoil. The barrel of the L7 is fitted with a bore evacuator
approximately halfway down its length. It is eccentric
ally mounted, which is a key recognition feature.
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
most successful tank gun
Tank gun
A tank gun is the main armament of a tank. Modern tank guns are large-caliber high-velocity guns, capable of firing kinetic energy penetrators, high explosive anti-tank rounds, and in some cases guided missiles. Anti-aircraft guns can also be mounted to tanks.-Overview:Tank guns are a specific...
. The L7 was a 105 mm L/52 rifled design intended for use in armoured fighting vehicle
Armoured fighting vehicle
An armoured fighting vehicle is a combat vehicle, protected by strong armour and armed with weapons. AFVs can be wheeled or tracked....
s. It was so successful that it armed not only British post-war designs, but was used almost universally in "the West" as the main armament of almost every main battle tank
Main battle tank
A main battle tank , also known as a battle tank or universal tank, is a tank that fills the heavy direct fire role of many modern armies. They were originally conceived to replace the light, medium, heavy and super-heavy tanks. Development was spurred onwards in the Cold War with the development...
of the period.
The L7 was developed by Britain's Royal Ordnance Factories to equip British tanks of the postwar (Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
) period as the successor to the 20 pounder
Ordnance QF 20 pounder
The Ordnance QF 20 pounder was a British 84 mm tank gun introduced in 1948 and used in the Centurion tank and the Charioteer tank destroyer...
(84 mm) used on Britain's postwar tank—the Centurion
Centurion tank
The Centurion, introduced in 1945, was the primary British main battle tank of the post-World War II period. It was a successful tank design, with upgrades, for many decades...
.
The L7 was a popular weapon and it was maintained in use even after it was superseded by the L11 series 120 mm
Royal Ordnance L11A5
The Royal Ordnance L11A5 is a 120 mm L/55 rifled tank gun design. It was the first of NATO's 120mm tank guns which became the standard calibre for Western tanks in the later period of the Cold War...
rifled tank gun, for some Centurion tanks operating as Artillery Forward Observation and Armoured Vehicle, Royal Engineers
Royal Engineers
The Corps of Royal Engineers, usually just called the Royal Engineers , and commonly known as the Sappers, is one of the corps of the British Army....
(AVRE
Avre
Avre may refer to:*Avre , a river in northwestern France, tributary of the Eure*Avre , a river in northern France, tributary of the Somme*Armoured Vehicle Royal Engineers, a military vehicle of the British Army...
) vehicles. The L7, and adaptations of it, can be found today as standard or retrofitted equipment on a wide variety of tanks developed during the Cold War. It is also being used as the main armament of the U.S. Army
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 Stryker
Stryker
The IAV Stryker is a family of eight-wheeled, 4-wheel-drive , armored fighting vehicles derived from the Canadian LAV III and produced by General Dynamics Land Systems, in use by the United States Army. The vehicle is named for two American servicemen who posthumously received the Medal of Honor:...
-based Mobile Gun System.
History
D-10 tank gun
The D-10 is a Soviet antitank gun developed in late World War II, and installed in tank destroyers and tanks. Versions of the 100 mm gun were installed on new T-55 tanks as late as 1979, and continue to be in active service in many countries.- History :...
, British officials decided that the 20 pounder
Ordnance QF 20 pounder
The Ordnance QF 20 pounder was a British 84 mm tank gun introduced in 1948 and used in the Centurion tank and the Charioteer tank destroyer...
was apparently incapable of defeating it. Hence there was a need to adopt a 105 mm gun.
The L7 was specifically designed to fit into the turret mountings of the 20 pounder. This would enable the Centurions to be upgunned with minimum modifications, hence the fleet could be upgraded in a shorter time and at a lower cost.
The first tank to be equipped with the L7 was the Centurion Mark 5 in 1959. The gun was subsequently adopted by several other nations for their own MBT
Main battle tank
A main battle tank , also known as a battle tank or universal tank, is a tank that fills the heavy direct fire role of many modern armies. They were originally conceived to replace the light, medium, heavy and super-heavy tanks. Development was spurred onwards in the Cold War with the development...
s, most notably the German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
Leopard 1 (for which the L7A3 variant was developed), the Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
ese Type 74
Type 74
The is a main battle tank of the Japan Ground Self-Defense Force . It was built by Mitsubishi Heavy Industries as a replacement for the earlier Type 61. It was based on the best features of a number of contemporary designs, placing it in the same class as the US M60 or German Leopard 1. Like...
(produced under license by Japan Steel Works
Japan Steel Works
is a steel manufacturer founded in Muroran, Hokkaidō, Japan in 1907.-History:Japan Steel Works was set up with investment from British firms Vickers and Armstrong Whitworth. During World War II, they manufactured what was then the world's largest gun barrel to be fitted on the battleship Yamato...
), the Swedish
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
Stridsvagn 103
Stridsvagn 103
The Stridsvagn 103 , or S-Tank , was a Swedish post-war main battle tank. It was known for its unconventional turret-less design, with a fixed gun traversed by engaging the tracks and elevated by adjusting the hull suspension...
(as the L74, with a longer barrel and automatic loader
Autoloader
An autoloader or auto-loader is a mechanical aid or replacement for the personnel that load ordnance into crew-served weapons, such as tanks and artillery...
), India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
for its upgraded T-55
T-55
The T-54 and T-55 tanks were a series of main battle tanks designed in the Soviet Union. The first T-54 prototype appeared in March 1945, just before the end of the Second World War. The T-54 entered full production in 1947 and became the main tank for armored units of the Soviet Army, armies of...
A, the US
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
M60 series
M60 Patton
The 105 mm Gun Full Tracked Combat Tank, M60, also known unofficially as the M60 Patton, is a first-generation main battle tank introduced in December 1960. It was widely used by the U.S. and its Cold War allies, especially those in NATO, and remains in service throughout the world today...
and earliest versions of the M1 Abrams
M1 Abrams
The M1 Abrams is a third-generation main battle tank produced in the United States. It is named after General Creighton Abrams, former Army Chief of Staff and Commander of US military forces in Vietnam from 1968 to 1972. The M1 is a well armed, heavily armored, and highly mobile tank designed for...
(with the M68), and the Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
i Merkava
Merkava
The Merkava is a main battle tank used by the Israel Defense Forces. The tank began development in 1974 and was first introduced in 1978. Four main versions of the tank have been deployed. It was first used extensively in the 1982 Lebanon War...
. In addition, several countries have used the gun to improve the firepower of existing main battle tanks. Derivatives have even been mounted in Warsaw Pact-built T-54 and T-55 tanks in Israel, Egypt and Iraq, and Type 79
Type 69/79
The Type 69 and Type 79 are two models of Chinese main battle tanks. Both developments of the Type 59 , they were the first independently-developed main battle tanks by China. Their lineage can be seen through the distinct gap between the first and second roadwheels...
tanks in China.
Design
The breech uses a horizontally-sliding breechblockBreechblock
A breechblock is the part of the firearm action that closes the breech of a weapon at the moment of firing....
for loading the fixed cartridge
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
cases. The gun recoil
Recoil
Recoil is the backward momentum of a gun when it is discharged. In technical terms, the recoil caused by the gun exactly balances the forward momentum of the projectile and exhaust gasses, according to Newton's third law...
s approximately 29 cm (in most applications), automatically ejecting the empty cartridge case upon reaching full recoil. The barrel of the L7 is fitted with a bore evacuator
Bore evacuator
A bore evacuator is a device on the gun barrel of an armoured fighting vehicle which helps prevent poisonous propellant gases from venting back into the vehicle's fighting compartment when the gun breech is opened to load another round. Bore evacuators are most often used on large-calibre tank...
approximately halfway down its length. It is eccentric
Eccentric (mechanism)
In mechanical engineering, an eccentric is a circular disk solidly fixed to a rotating axle with its centre offset from that of the axle ....
ally mounted, which is a key recognition feature.
Specification
- Calibre: 105 mm (4.13 in)
- Shell: 105×607 mm R , 105×617 mm R
- Barrel length: 52 calibres
- Weight: 1,282 kgKilogramThe kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
(2,826 lbs) - Length: 5.89 m (19.3 ft)
- Rate of fire: 10 rounds per minuteMinuteA minute is a unit of measurement of time or of angle. The minute is a unit of time equal to 1/60th of an hour or 60 seconds. In the UTC time scale, a minute on rare occasions has 59 or 61 seconds; see leap second. The minute is not an SI unit; however, it is accepted for use with SI units...
(maximum)
Ammunition Available
- APDS
- APERS-T ("Anti-personnel-tracer")
- APFSDS: 1,475 m/s
- Dummy
- HE: 1,174 m/s
- HEAT
- HESHHigh explosive squash headHigh explosive squash head is a type of explosive ammunition that is effective against buildings and is also used against tank armour. It was fielded chiefly by the British Army as the main explosive round of its main battle tanks during the Cold War...
: 737 m/s - Smoke-White phosphorus incendiary
- Target Practice
- Target Practice Discarding SabotSabotA sabot is a device used in a firearm or cannon to fire a projectile, such as a bullet, that is smaller than the bore diameter, or which must be held in a precise position. The term is also applied to a battery stub case, a device used similarly to make a small electrical battery usable in a...
Variants
- L7A1
- Standard British production variant.
- L7A3
- Variant for the (West) German Leopard 1 MBT. The upper rear corner of the breech block reduced in size so gun can be depressed without hitting the turret roof.
- L74
- SwedishSwedenSweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
variant with a 62 calibre (6.51 m) barrel used only for the Stridsvagn 103Stridsvagn 103The Stridsvagn 103 , or S-Tank , was a Swedish post-war main battle tank. It was known for its unconventional turret-less design, with a fixed gun traversed by engaging the tracks and elevated by adjusting the hull suspension...
MBT.- M68
- USUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
built variant for M60 PattonM60 PattonThe 105 mm Gun Full Tracked Combat Tank, M60, also known unofficially as the M60 Patton, is a first-generation main battle tank introduced in December 1960. It was widely used by the U.S. and its Cold War allies, especially those in NATO, and remains in service throughout the world today...
. Uses a round breech with a vertically-sliding breechblockBreechblockA breechblock is the part of the firearm action that closes the breech of a weapon at the moment of firing....
, and a different design of bore evacuator. Also used on the M1 AbramsM1 AbramsThe M1 Abrams is a third-generation main battle tank produced in the United States. It is named after General Creighton Abrams, former Army Chief of Staff and Commander of US military forces in Vietnam from 1968 to 1972. The M1 is a well armed, heavily armored, and highly mobile tank designed for...
up until its replacement by the M256 on the M1A1. Used on Israeli tanks up until the Merkava III- M68A1E4
- Variant of the U.S. M68 designed for use on the Stryker MGS, fitted with an automatic loader.
- KM68A1
- Republic of Korea ArmyRepublic of Korea ArmyThe Republic of Korea Army is the largest of the military branches of the South Korean armed forces with 520,000 members as of 2010...
's license-produced variant of the U.S. M68 gun. Used on M48A3KM48 PattonThe M48 Patton is a medium tank that was designed in the United States. It was the third and final tank to be officially named after General George S. Patton, commander of the U.S. Third Army during World War II and one of the earliest American advocates for the use of tanks in battle It was a...
, M48A5KM48 PattonThe M48 Patton is a medium tank that was designed in the United States. It was the third and final tank to be officially named after General George S. Patton, commander of the U.S. Third Army during World War II and one of the earliest American advocates for the use of tanks in battle It was a...
and K1K1 Type 88The K1 is a South Korean third-generation main battle tank in use with the Republic of Korea Armed Forces, developed by Hyundai Precision...
tanks.- Type 79/81/83
- Chinese copies of an L7 supplied by Austria.
- FM K.4 Modelo 1L
- Argentine ArmyArgentine ArmyThe Argentine Army is the land armed force branch of the Armed Forces of the Argentine Republic and the senior military service of the country.- History :...
's license produced by Fabricaciones Militares in ArgentinaArgentinaArgentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. Used on the TAMTAM (tank)The Tanque Argentino Mediano , or TAM, is the main battle tank in service with the Argentine Army. Lacking the experience and resources to design a tank, the Argentine Ministry of Defense contracted German company Thyssen-Henschel...
medium tank.
Usage
- CenturionCenturion tankThe Centurion, introduced in 1945, was the primary British main battle tank of the post-World War II period. It was a successful tank design, with upgrades, for many decades...
- and derivatives such as Olifant
- EE-T1 OsórioEE-T1 OsórioThe Engesa EE-T1 Osório was a Brazilian main battle tank prototype. It was developed as a privately funded venture by Engesa, with little government support. It was intended to be sold first to Arab and other Third World countries, jump-starting production — and enabling the Brazilian Army to later...
- Leopard 1
- M1 AbramsM1 AbramsThe M1 Abrams is a third-generation main battle tank produced in the United States. It is named after General Creighton Abrams, former Army Chief of Staff and Commander of US military forces in Vietnam from 1968 to 1972. The M1 is a well armed, heavily armored, and highly mobile tank designed for...
in early models (the M1 and M1IP models) - M47 PattonM47 PattonThe M47 Patton is an American medium tank, the second tank to be named after General George S. Patton, commander of the U.S. Third Army during World War II and one of the earliest American advocates of tanks in battle. It was a further development of the M46 Patton tank.-History:The M47 was the U.S...
in some upgraded variants (examples: Spanish M47E1 and M47E2) - M48 PattonM48 PattonThe M48 Patton is a medium tank that was designed in the United States. It was the third and final tank to be officially named after General George S. Patton, commander of the U.S. Third Army during World War II and one of the earliest American advocates for the use of tanks in battle It was a...
in some upgraded variants (M48A5, IsraelIsraelThe State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
i-rebuilt M48s, etc.) - K1 Type 88K1 Type 88The K1 is a South Korean third-generation main battle tank in use with the Republic of Korea Armed Forces, developed by Hyundai Precision...
- M60 Patton TankM60 PattonThe 105 mm Gun Full Tracked Combat Tank, M60, also known unofficially as the M60 Patton, is a first-generation main battle tank introduced in December 1960. It was widely used by the U.S. and its Cold War allies, especially those in NATO, and remains in service throughout the world today...
- MerkavaMerkavaThe Merkava is a main battle tank used by the Israel Defense Forces. The tank began development in 1974 and was first introduced in 1978. Four main versions of the tank have been deployed. It was first used extensively in the 1982 Lebanon War...
I and II - OF-40OF-40The OF-40 tank is a main battle tank developed as a joint venture between OTO Melara and FIAT, and intended primarily for export sales. OTO Melara would develop and produce the hulls, and automotive components would be provided by FIAT...
- CM11 Brave Tiger
- Pz-61 & Pz-68
- Stingray light tankStingray Light TankThe Stingray Light Tank is a light tank produced by Textron Marine and Land Systems Division . It was originally developed for the U.S. Army's Armored Gun System competition. Thailand is the only user.- Stingray :...
- Stridsvagn 103Stridsvagn 103The Stridsvagn 103 , or S-Tank , was a Swedish post-war main battle tank. It was known for its unconventional turret-less design, with a fixed gun traversed by engaging the tracks and elevated by adjusting the hull suspension...
- StrykerStrykerThe IAV Stryker is a family of eight-wheeled, 4-wheel-drive , armored fighting vehicles derived from the Canadian LAV III and produced by General Dynamics Land Systems, in use by the United States Army. The vehicle is named for two American servicemen who posthumously received the Medal of Honor:...
MGS - T-54 in several upgraded variants (for example Israeli Tiran-4Sh)
- T-55T-55The T-54 and T-55 tanks were a series of main battle tanks designed in the Soviet Union. The first T-54 prototype appeared in March 1945, just before the end of the Second World War. The T-54 entered full production in 1947 and became the main tank for armored units of the Soviet Army, armies of...
in several upgraded variants (for example Egyptian modified T-55s) - TAM medium tankTAM (tank)The Tanque Argentino Mediano , or TAM, is the main battle tank in service with the Argentine Army. Lacking the experience and resources to design a tank, the Argentine Ministry of Defense contracted German company Thyssen-Henschel...
- Type 74Type 74The is a main battle tank of the Japan Ground Self-Defense Force . It was built by Mitsubishi Heavy Industries as a replacement for the earlier Type 61. It was based on the best features of a number of contemporary designs, placing it in the same class as the US M60 or German Leopard 1. Like...
- VijayantaVijayantaThe Vijayanta main battle tank was built in India based on a licensed design of the Vickers Mk.1. The Vijayanta was the first indigenous tank of the Indian army. The prototype was completed in 1963 and the tank entered service in 1965. The first 90 vehicles were built by Vickers in the UK...
- Ramses II
- Centauro 8x8
- EE-T1 Osório