The Royal Ordnance L7, officially designated Gun, 105 mm, Tank, L7, is the basic model of the United Kingdom's most successful

tank gun A tank gun is the main armament of a tank. Modern tank guns are high-velocity, large-caliber artilleries capable of firing kinetic energy penetrators, high-explosive anti-tank, and cannon-launched guided projectiles. Anti-aircraft guns can also ...

. It is a

105 mm 105 mm (4.1 in) is a common NATO-standard artillery and tank gun calibre. The rifled tank round is defined by STANAG 4458. The artillery round is defined by AOP-29 part 3 with reference to STANAG 4425. Artillery Since the early 21st century, mos ...

L/52 rifled design by the

Royal Ordnance Factories Royal may refer to: People * Royal (name), a list of people with either the surname or given name * A member of a royal family or royalty Places United States * Royal, Arkansas, an unincorporated community * Royal, Illinois, a village * Royal, ...

, intended for use in

armoured fighting vehicle An armoured fighting vehicle (British English) or armored fighting vehicle (American English) (AFV) is an armed combat vehicle protected by vehicle armour, armour, generally combining operational mobility with Offensive (military), offensive a ...

s, replacing the older QF 20-pounder (84 mm) gun mounted on the British

Centurion In the Roman army during classical antiquity, a centurion (; , . ; , or ), was a commander, nominally of a century (), a military unit originally consisting of 100 legionaries. The size of the century changed over time; from the 1st century BC ...

tank. The successful L7 gun has been fitted on many armoured vehicles, including the Centurion (starting from the Mk. 5/2 variant), the German

Leopard 1 The Kampfpanzer Leopard, subsequently Leopard 1 following the introduction of the successive Leopard 2, is a main battle tank designed by Porsche and manufactured by Krauss-Maffei Wegmann, Krauss-Maffei in West Germany, first entering service ...

and, in an altered design, as the M68 gun in several variants of the US

M48 Patton The M48 Patton is an American first-generation main battle tank (MBT) introduced in February 1952, being designated as the 90mm Gun M48, armored, full-tracked, combat vehicle of the medium-gun tank class. It was designed as a replacement for ...

and M60. The L7 is a popular weapon and continued in use even after it was superseded by the L11 series 120 mm rifled tank gun, for some Centurion tanks operating as Artillery Forward Observation and Armoured Vehicle, Royal Engineers (AVRE)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 as standard or retrofitted equipment on a wide variety of tanks developed during the Cold War.

History

Both the United Kingdom and the United States had been developing projects for high calibre guns during WWII in order to compete with increasingly heavily armoured German tanks, and later for

Cold War The Cold War was a period of global Geopolitics, geopolitical rivalry between the United States (US) and the Soviet Union (USSR) and their respective allies, the capitalist Western Bloc and communist Eastern Bloc, which lasted from 1947 unt ...

Soviet tanks. The US developed several heavy tank designs during this period, notable were the US 105 mm gun motor carriage T95 (also known as "super-heavy tank T28") as well as the QF 32-pounder mounted on the British A39

Tortoise heavy assault tank The Tortoise heavy assault tank (A39) was a British heavy tank, heavy assault gun tank design developed during the World War II, Second World War, but never put into mass production. It was developed for the task of clearing heavily fortified ...

. The US foresaw difficulties in engagements against the Soviet IS-3 and 4 with its M47 Patton. This led to the introduction of the M103, a

heavy tank A heavy tank is a tank classification produced from World War I to the end of the Cold War. These tanks generally sacrificed mobility and maneuverability for better armour protection and equal or greater firepower than tanks of lighter classes. ...

designed to counter

Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

heavy tanks. It mounted an extremely powerful 120 mm cannon but the ammunition was so large that it required two loaders, one for the shell and another for the separate propellant charge. Of the 300 M103s built, most went to the Marines. The UK came to the same conclusions and developed their own heavy tank, the Conqueror, which mounted the L1 120 mm gun.

United Kingdom

During the

Hungarian Revolution of 1956 The Hungarian Revolution of 1956 (23 October – 4 November 1956; ), also known as the Hungarian Uprising, was an attempted countrywide revolution against the government of the Hungarian People's Republic (1949–1989) and the policies caused by ...

, a Soviet T-54A medium tank was driven onto the grounds of the

British embassy This is a list of diplomatic missions of the United Kingdom of Great Britain and Northern Ireland, excluding honorary consulates. The UK has one of the largest global networks of diplomatic missions. UK diplomatic missions to capitals of other Co ...

Budapest Budapest is the Capital city, capital and List of cities and towns of Hungary, most populous city of Hungary. It is the List of cities in the European Union by population within city limits, tenth-largest city in the European Union by popul ...

by the Hungarians in November. After a brief examination of this tank's armour and 100 mm gun, British officials decided that the 20-pounder was apparently incapable of defeating its frontal armour. This meant the most common British tanks were no longer able to effectively deal with Soviet medium tank designs, let alone their heavy tanks. These events spurred the United Kingdom to employ a new high-velocity tank gun in 1958, the Royal Ordnance L7 to keep existing Centurion tanks viable against this new Soviet tank design. While the United States began design development of the XM60 tank in 1957 and began user trials of the weapon in 1958. The L7 was specifically designed to fit into the turret mountings of the 20 pounder. This would enable the

tanks to be up-gunned with minimum modifications; hence, the fleet could be upgraded in a shorter time and at a lower cost. The first production tank to integrate the L7 was a single up-armoured Centurion Mark 7 in 1958 which was to prove the future viability of up-armouring and up-gunning the Centurion. From 1959 onwards newly built Centurions incorporated the L7 at production.

Other users

The gun was subsequently adopted for use on the German

(for which the L7A3 variant was developed). In addition, several countries have used the gun to improve the

firepower Firepower is the military capability to direct force at an enemy. It involves the whole range of potential weapons. The concept is generally taught as one of the three key principles of modern warfare wherein the enemy forces are destroyed or ...

of existing main battle tanks. Derivatives have even been mounted in Warsaw Pact-built T-54 and T-55 tanks in Israel, India, Egypt and Iraq, and Type 79 tanks in China.

Specification (L7A1)

*Calibre: 105 mm (4.13 in) *Length: *Barrel length: 52 calibres, *Recoil length: *Weight: *Rate of fire: 10 rounds per

minute A minute is a unit of time defined as equal to 60 seconds. It is not a unit in the International System of Units (SI), but is accepted for use with SI. The SI symbol for minutes is min (without a dot). The prime symbol is also sometimes used i ...

(maximum), 6 rounds per

(normal) *Barrel life: 200 EFC (800 with additives) *Maximum effective range: (APDS), (HESH) *Cartridge:

105×617mmR The 105×617mm (4.1 inch), also known as 105×617mmR, is a common, NATO-standard, tank gun cartridge used in 105 mm guns such as those derived from the Royal Ordnance L7. The 105×617mmR cartridge was originally developed from the calibre ...

Variants

UK models

* L7A1 :Standard UK production variant. * L7A2 :L7A1 fitted with a thermal sleeve. * L7A3 :Variant for the (West) German

MBT. The upper rear corner of the breech block reduced in size so gun can be depressed without hitting the turret roof. * L7A4 :L7A3 fitted with an Ernest Leitz Canada muzzle reference sensor. Used by the Belgian Leopard 1A5 (BE) and Canadian Leopard C1. * L7 LRF Royal Thai Army Stingray tanks Cobra Gold 2019 live fire 2

Royal Thai Army Stingray tanks Cobra Gold 2019 live fire 2

:Low Recoil Force (LRF) version of the L7 used by the

Stingray light tank The Stingray, sometimes known as the Commando Stingray, is a light tank produced by Textron Marine & Land Systems division (formerly Cadillac Gage). The Stingray was a private venture project aimed at foreign countries. As of 2020, Textron has ...

. * JSW 105mm L7A1 L/51 :Japanese version of the first model produced on license for the Type 74 MBT. This version has an indigenous breech. * Royal Ordnance 105mm IWS :A development by Royal Ordnance designated Improved Weapon System with an increased chamber pressure and a longer barrel length of L/63.4. * FM K.4 Modelo 1L :

Argentine Army The Argentine Army () is the Army, land force branch of the Armed Forces of the Argentine Republic and the senior military service of Argentina. Under the Argentine Constitution, the president of Argentina is the commander-in-chief of the Armed For ...

's licence produced by

Fabricaciones Militares Fabricaciones Militares Sociedad del Estado (Spanish for Military Industries State Corporation) is a state-owned Argentine arms manufacturer based in Buenos Aires. The company was a government agency under the name Dirección General de Fabricacio ...

in Argentina. Used on the TAM medium tank. Also designated as "105 mm FRT L51 Tank Gun".

Chinese models

*Type 79/81/81A/83 :Chinese produced L7. Licence procured from Austria. * ZPL-79 :Chinese licence-built designation for the L7A3 with replaceable indigenous thermal sleeve. Also known as Type 79. It was mounted on the Type 80 tank prototypes. * ZPL-81/A :Modified Type 79. ZPL-81A has improved thermal sleeve. First seen on the Type 59-II tank. * ZPL-83/A :Modified Type 81 with longer barrel and improved construct material. Also known as Type 83. It was fitted on the Type 59D1, Type 63HG, Type 79 tank and Type 88B tank. * ZPL-94 :Modified Type 83 with longer barrel at 62 caliber. Mounted on Type 59D tank and Type 88A tank. Type 88A main battle tank

* ZPL-98 :Modified Type 83A rifled gun with an indigenous low recoil

muzzle brake A muzzle brake or recoil compensator is a device connected to, or a feature integral (ported barrel) to the construction of, the muzzle or barrel of a firearm or cannon that is intended to redirect a portion of propellant gases to counter re ...

and lighter weight. It was mounted on the

Type 63A The Type 63A (; also known as the ZTS63A) is an amphibious light tank upgraded from the Type 63, designed for river-crossing operations at inland rivers and lakes. Its industrial designation is WZ213. The Type 63A is being replaced by the ZT ...

amphibious tank. Also known as Type 98 rifled gun. *ZPL-98A :Modified Type 98 rifled gun, mounted on ZTD-05 and ZTL-11.

Other developments

*GT-3 :South African variant built by

Denel Denel SOC Ltd is a South African state-owned aerospace and military technology conglomerate established in 1992. It was created when the manufacturing subsidiaries of Armscor were split off in order for Armscor to become the procurement agency ...

for converting Centurion with 20-pounder gun into Olifant tanks. GT-3 retained the breach assemblies of 20-pounder paired with the modified copy of L7 barrel. *GT-7 :South African variant built by Denel for the Olifant Mk1A and Rooikat 105. Incorporates a heavily modified recoil assembly. *Rheinmetall Rh-105 family :Multiple variants of 105 mm tank gun developed from L7 by

Rheinmetall Rheinmetall AG () is a German automotive and arms manufacturer, headquartered in Düsseldorf, Germany. The group was promoted to the DAX, Germany's leading stock market index, in March 2023. It is the largest German and fifth largest Europe ...

of Germany for commercial market. The family consisted of Rh 105–60, Rh 105–40, Rh 105–30, Rh 105–20, and Rh 105-11. The last two numbers on the designation denotes the gun recoil force in metric ton. The Rh 105-20 and -11 models were fitted with muzzle brake and intended to be mounted on light tanks and wheeled armored vehicles. The variants has been fitted as modification on various armored vehicles, such as Rh 105-30 on Spanish M47E2, Rh 105-20 on Ikv 91 and

AMX-10 RC The AMX-10 RC is a French armoured fighting vehicle manufactured by Nexter Systems for armoured reconnaissance purposes. Equipping French cavalry units since 1979,https://imagesdefense.gouv.fr/fr/remise-du-premier-vehicule-amx-10-rc-au-2e-rh-r ...

, and Rh 105-11 on MOWAG Shark. *L74 :Swedish model built by

Bofors AB Bofors ( , , ) is a former Swedish arms manufacturer which today is part of the British arms manufacturer BAE Systems. The name has been associated with the iron industry and artillery manufacturing for more than 350 years. History Locate ...

for the

Strv 103 The Stridsvagn 103 (Strv 103), also known as the Alternative S and S-tank, is a Swedish Cold War-era main battle tank, designed and manufactured in Sweden. "Strv" is the Swedish military abbreviation of ''stridsvagn'', Swedish for tank (literal ...

using more sophisticated recoil assembly and a longer L/62 gun tube for increased muzzle-velocity and accuracy.

Usage

L7 variant

: L7A1 cannon on late Centurion models and derivatives such as Olifant *

Vickers MBT The Vickers MBT is a series of main battle tanks (MBTs) developed as a private venture by British company Vickers-Armstrongs for export. The design makes use of proven components, such as the L7 gun of the Centurion tank, Centurion, the Leyland ...

: Mark 1,

Mark 3 Mark 3 is the third chapter of the Gospel of Mark in the New Testament of the Christian Bible. It relates a conflict over healing on the Sabbath, the commissioning of the Twelve Apostles, a conflict with the Jerusalem scribes and a meeting of ...

, and

Mark 4 Mark 4 is the fourth chapter of the Gospel of Mark in the New Testament of the Christian Bible. It tells the parable of the Sower, with its explanation, and the parable of the Mustard Seed. Both of these parables are paralleled in Matthew and ...

models **

Vijayanta The ''Vijayanta'' () was a main battle tank 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 on Decem ...

: L7A3 cannon * Leopard 2AV: Some of the prototype fitted with L7A3 *

: in some upgraded variants **M48A2GA2: West German modification **Super M48: German modernization of M48A2 or M48A3 **M48A5E: Spanish modification **M48A5T2: Turkish modification *

: LRF cannon *

M41 Walker Bulldog The M41 Walker Bulldog, officially 76-mm gun tank M41, was an American light tank developed for armed reconnaissance purposes. It was produced by Cadillac between 1951 and 1954 and marketed successfully to the United States Army as a replaceme ...

: LRF cannon on M41 105 variant *

LAV-600 The Cadillac Gage LAV-600, also known as the V-600,Army Weaponry and Equipment, Page 469. Army: The Magazine of Landpower. Volume 36, Issue No 10. October 1986. is an American light armored 6×6 wheeled vehicle, derived from the LAV-300. Develope ...

: LRF cannon *

T-54/55 The T-54 and T-55 tanks are a series of Soviet medium tanks introduced in the years following the Second World War. The first T-54 prototype was completed at Nizhny Tagil by the end of 1945.Steven Zaloga, T-54 and T-55 Main Battle Tanks 1944–2 ...

: in some upgraded variants ** Type 59-II: Chinese modification of T-54 ** Type 59 Royal Ordnance: British modernization of Type 59 ** Tiran-4Sh: Israeli modification of T-54, both L7 and M68 variants fitted ** Tiran-5Sh: Israeli modification of T-55, both L7 and M68 variants fitted ** T-55M3: Israeli modernization of T-54/55 ** T-55 "Gulmohar": Indian modernization of T-55 ** M-55S: Slovenian modernization of T-55 ** Type 72Z/Safir-74: Iranian modernization of T-55 * Charioteer: A single prototype up-gunned with L7 cannon * FV4401 Contentious: The only prototype was later up-gunned with L7 cannon * Panzer 58: Production model *

Panzer 61 The Panzer 61 was a Switzerland, Swiss Cold War era medium tank later reclassified as a List of main battle tanks by generation, second-generation main battle tank. The tank had a weight of 36.5 tons and was powered by a 630 hp diesel engine, ...

Panzer 68 The Panzer 68 was a Swiss main battle tank developed by the Eidgenoessische Konstruktionswerkstaette in Thun in the late 1960s, and was the main tank of the Swiss Army until the late 1990s. History The Panzer 68 was based on the Panzer 61, ...

* TAM medium tank * Rooikat 105 * TH-400 and TH-800 * Tiam MBT

ZPL variant

: ZPL-83 in some upgraded kits sold by China * Type 59: in some upgraded variants **Type 59-II: ZPL-79, ZPL-81 **Type 59-IIA: ZPL-81A **Type 59D1: ZPL-83A **Type 59D: ZPL-94 * Type 69: in some upgraded variants ** Type 69-IIG: An upgraded Bangladeshi variant of

Type 69 tank The Type 69 () and Type 79 () are Chinese first generation main battle tanks. Both were developments of the Type 59 medium tank (a locally produced Soviet T-54A) with technologies derived from the T-62. They were the first indigenously devel ...

** Type 79: ZPL-83 ** Type 79-II: ZPL-83A * Type 80: ZPL-79 **Type 85-I: ZPL-79 **Type 85-II: ZPL-94 **Type 88: ZPL-83A **Type 88A: ZPL-94 * Type 62G: ZPL-98 modification * Type 63: in some upgraded variants **Type 63HG: ZPL-83A modification **

: ZPL-98 *MMT-40:

Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...

-built light tank with WMA301 turret and gun * WMA301: Modified ZPL-94 *

ST-1 ST-1 is a communications satellite owned by Singapore Telecom and Taiwan's Chunghwa Telecom Company, Ltd. It was placed launched on 25 August 1998, by an Ariane 4 rocket. The two companies jointly operate the spacecraft from control centres loc ...

: Modified ZPL-94 * ST-2: Modified ZPL-94 * ZTD-05: ZPL-98A * ZTL-11: ZPL-98A * ZTQ-15: Modified ZPL-94

Related designs with compatible ammunition

* MB-3 Tamoyo III *

EE-T1 Osório The Engesa EE-T1 ''Osório'' was a Brazilian main battle tank prototype developed by Engesa. The tank was intended to be sold first to Arab and other Third World countries, jump-starting production — and enabling the Brazilian Army to later pla ...

* OF-40 *

* VT 1-1 *

M47 Patton The M47 Patton was an American medium tank, a development of the M46 Patton mounting an updated turret, and was in turn further developed as the M48 Patton. It was the second American tank to be named after General George S. Patton, commande ...

: in some upgraded variants **M47E2: Spanish modification armed with a Rheinmetall RH-105/30 gun **M47 OTO: Italian modification armed with an

OTO Melara OTO Melara was a subsidiary of the Italian company Finmeccanica, today Leonardo, active in the defence sector, with factories in Brescia and La Spezia. From 1 January 2016, the activities of OTO Melara merged into Leonardo's Defence Systems ...

105 mm/52 gun * Marder Medium Tank: Marder IFV armed with OTO Melara 105 mm/52 gun *

B1 Centauro The Centauro is a family of Italian military vehicles originating from a wheeled tank destroyer for light to medium territorial defense and tactical reconnaissance. It was developed by a consortium of manufacturers, the Società Consortile Iveco ...

: Italian wheeled armored vehicle with OTO Melara 105mm/52 gun * Type 16 maneuver combat vehicle: Japanese wheeled armored vehicle with

Japan Steel Works The is a steel manufacturer founded in Muroran, Hokkaidō, Japan in 1907. History Japan Steel Works was set up with investment from British firms Vickers, Armstrong Whitworth and Mitsui. During World War II, they manufactured what was then t ...

105 mm/52 gun

References

Bibliography

* * * Starry, Donn A., General. "Mounted Combat In Vietnam." Vietnam Studies.

Department of the Army The United States Department of the Army (DA) is one of the three military departments within the United States Department of Defense. The DA is the federal government agency within which the United States Army (U.S.) is organized. It is led ...

. First printing 1978. * Zaloga, Steven J. and Hugh Johnson (2004). ''T-54 and T-55 Main Battle Tanks 1944–2004''. Oxford: Osprey. {{Post WWII British tank guns Cold War artillery of the United Kingdom Tank guns of the United Kingdom 105 mm artillery Military equipment introduced in the 1950s