
A main battle tank (MBT), also known as a battle tank, is a tank that fills the role of armour-protected direct fire and maneuver in many modern armies. Cold War-era development of more powerful engines, better suspension systems and lighter composite armour allowed for the design of a tank that had the firepower of a super-heavy tank, the armour protection of a heavy tank, and the mobility of a light tank, in a package with the weight of a medium tank. The first designated MBT was the British Chieftain tank, which during its development in the 1950s was re-designed as an MBT. Throughout the 1960s and 1970s, the MBT replaced almost all other types of tanks, leaving only some specialist roles to be filled by lighter designs or other types of armoured fighting vehicles.
Main battle tanks are a key component of modern armies. Modern MBTs seldom operate alone, as they are organized into armoured units that include the support of infantry, who may accompany the tanks in infantry fighting vehicles. They are also often supported by surveillance or ground-attack aircraft. The average weight of MBTs varies from country to country. The average weight of Western MBTs is usually greater than that of Russian or Chinese MBTs.

During World War I, combining tracks, armour, and guns into a functional vehicle pushed the limits of mechanical technology. This limited the specific battlefield capabilities any one tank design could be expected to fulfill. A design could have good speed, armour, or firepower, but not all three together.
Facing the deadlock of trench warfare, the first tank designs focused on crossing wide trenches, requiring very long and large vehicles, such as the British Mark I tank and successors; these became known as heavy tanks. Tanks that focused on other combat roles were smaller, like the French Renault FT; these were light tanks or tankettes. Many late-war and inter-war tank designs diverged from these according to new, and mostly untried, concepts for future tank roles and tactics. Each nation tended to create its own list of tank classes with different intended roles, such as "cavalry tanks", "breakthrough tanks", "fast tanks", and "assault tanks". The British maintained cruiser tanks that in order to achieve high speed and hence manoeuvrability in the attack carried less armour, and infantry tanks which operating at infantryman pace could carry more armour.

After years of isolated and divergent development, the various interwar tank concepts were finally tested with the start of World War II. In the chaos of blitzkrieg, tanks designed for a single role often found themselves forced into battlefield situations they were ill-suited for. During the war, limited-role tank designs tended to be replaced by more general-purpose designs, enabled by improving tank technology. Tank classes became mostly based on weight (and the corresponding transport and logistical needs). This led to new definitions of heavy and light tank classes, with medium tanks covering the balance of those between. The German Panzer IV tank, designed before the war as a "heavy" tank for assaulting fixed positions, was redesigned during the war with armour and gun upgrades to allow it to take on anti-tank roles as well, and was reclassified as a medium tank.
The second half of World War II saw an increased reliance on general-purpose medium tanks, which became the bulk of the tank combat forces. Generally, these designs massed about 25–30 t (25–30 long tons; 28–33 short tons), were armed with cannons around 75 mm (3.0 in), and powered by engines in the 400–500 hp (300–370 kW) range. Notable examples include the Soviet T-34 (the most-produced tank at that time) and the US M4 Sherman.
Late war tank development placed increased emphasis on armour, armament, and anti-tank capabilities for medium tanks:

Britain had continued on the path of parallel development of cruiser tanks and infantry tanks. Development of the Rolls-Royce Meteor engine for the Cromwell tank, combined with efficiency savings elsewhere in the design, almost doubled the horsepower for cruiser tanks. This led to speculation of a "Universal Tank", able to take on the roles of both a cruiser and an infantry tank by combining heavy armour and manoeuvrability.[page needed]
Field Marshal Bernard Montgomery is acknowledged as the main advocate of the British universal tank concept as early as 1943, according to the writings of Giffard Le Quesne Martel, but little progress was made beyond development of the basic Cromwell cruiser tank that eventually led to the Centurion. The Centurion, at the time designated "heavy cruiser" and later "medium gun tank" was designed for mobility and firepower at the expense of armour,[citation needed] but more engine power permitted more armour protection, so the Centurion could also operate as an infantry tank, doing so well that development of a new tank was rendered unnecessary.
The Centurion, entering service just as World War II finished, was a multi-role tank that subsequently formed the main armoured element of the British Army of the Rhine, the armed forces of the British Empire and Commonwealth forces, and subsequently many other nations through exports, whose cost was met largely by the US. The introduction of the 84 mm (3.3 in) 20-pounder gun in 1948 gave the tank a significant advantage over other tanks of the era, paving the way for a new tank classification, the main battle tank, which gradually superseded previous weight and armament classes.

A surplus of effective WWII-era designs in other forces, notably the US and the Soviet Union, led to slower introductions of similar designs on their part. By the early 1950s, these designs were clearly no longer competitive, especially in a world of shaped charge weapons, and new designs rapidly emerged from most armed forces.
The Quebec conference in 1957 between the US, UK and Canada identified the MBT as the route for development rather than separate medium and heavy tanks.
The concept of the medium tank gradually evolved into the MBT in the 1960s, as it was realized that medium tanks could carry guns (such as the American 90 mm (3.5 in), Soviet 100 mm (3.9 in), and especially the British L7 105 mm (4.1 in)) that could penetrate any practical level of armour then existing at long range. Also, the heaviest tanks were unable to use most existing bridges. The World War II concept of heavy tanks, armed with the most powerful guns and heaviest armour, became obsolete because the large tanks were too expensive and just as vulnerable to damage by mines, bombs, rockets, and artillery. Likewise, World War II had shown that lightly armed and armoured tanks were of limited value in most roles. Even reconnaissance vehicles had shown a trend towards heavier weight and greater firepower during World War II; speed was not a substitute for armour and firepower.
An increasing variety of anti-tank weapons and the perceived threat of a nuclear war prioritized the need for additional armour. The additional armour prompted the design of even more powerful guns. The main battle tank thus took on the role the British had once called the "universal tank", exemplified by the Centurion, filling almost all battlefield roles. Typical main battle tanks were as well armed as any other vehicle on the battlefield, highly mobile, and well armoured. Yet they were cheap enough to be built in large numbers. The first Soviet main battle tank was the T-64A (the T-54/55 and T-62 were considered "medium" tanks) and the first American nomenclature-designated MBT was the M60 tank.

Anti-tank weapons rapidly outpaced armour developments. By the 1960s, anti-tank rounds could penetrate a meter of steel so as to make the application of traditional rolled homogeneous armour unpragmatic. The first solution to this problem was the composite armor of Soviet T-64 tank, which included steel-glass-reinforced textolite-steel sandwich in heavily sloped glacis plates, and steel turret with aluminum inserts, which helped to resist both high-explosive anti-tank (HEAT) and APDS shells of the era. Later came British Chobham armour. This composite armour used layers of ceramics and other materials to help attenuate the effects of HEAT munitions. Another threat came by way of the widespread use of helicopters in battle. Before the advent of helicopters, armour was heavily concentrated to the front of the tank. This new threat caused designs to distribute armour on all sides of the tank (also having the effect of protecting the vehicle's occupants from nuclear explosion radiation).
By the late 1970s, MBTs were manufactured by China, France, West Germany, Britain, India, Italy, Japan, the Soviet Union, Sweden, Switzerland, and the United States.
The Soviet Union made novel advancements to the weapon systems including mechanical autoloaders and anti-tank guided missiles. Autoloaders were introduced to replace the human loader, permitting the turret to be reduced in size, making the tank smaller and less visible as a target, while missile systems were added to extend the range at which a vehicle could engage a target and thereby enhance the first-round hit probability.
The United States's experience in the Vietnam War contributed to the idea among army leadership that the role of the main battle tank could be fulfilled by attack helicopters. During the Vietnam War, helicopters and missiles competed with MBTs for research money.
Though the Persian Gulf War reaffirmed the role of main battle tanks,[clarification needed] MBTs were outperformed by the attack helicopter. Other strategists considered that the MBT was entirely obsolete in light of the efficiency and speed with which coalition forces neutralized Iraqi armour.

In asymmetric warfare, threats such as improvised explosive devices and mines have proven effective against MBTs. In response, nations that face asymmetric warfare, such as Israel, are reducing the size of their tank fleet and procuring more advanced models. Conversely, some insurgent groups like Hezbollah themselves operate main battle tanks, such as the T-72.[citation needed]
The United States Army used 1,100 M1 Abrams in the course of the Iraq War. They proved to have an unexpectedly high vulnerability to improvised explosive devices. A relatively new type of remotely detonated mine, the explosively formed penetrator, was used with some success against American armoured vehicles. However, with upgrades to their rear armour, M1s proved to be valuable in urban combat; at the Second Battle of Fallujah the United States Marines brought in two extra companies of M1s. Britain deployed its Challenger 2 tanks to support its operations in southern Iraq.
Advanced armour has reduced crew fatalities but has not improved vehicle survivability. Small unmanned turrets on top of the cupolas called remote controlled weapon stations armed with machine guns or mortars provide improved defence and enhance crew survivability. Experimental tanks with unmanned turrets locate crew members in the heavily armoured hull, improving survivability and reducing the vehicle's profile.
Technology is reducing the weight and size of the modern MBT. A British military document from 2001 indicated that the British Army would not procure a replacement for the Challenger 2 because of a lack of conventional warfare threats in the foreseeable future. The obsolescence of the tank has been asserted, but the history of the late 20th and early 21st century suggested that MBTs were still necessary. During the Russian invasion of Ukraine, Western and Russian MBTs saw large-scale combat in large numbers.
The Organization for Security and Co-operation in Europe defines a main battle tank as "a self-propelled armoured fighting vehicle, capable of heavy firepower, primarily of a high muzzle velocity direct fire main gun necessary to engage armoured and other targets, with high cross-country mobility, with a high level of self-protection, and which is not designed and equipped primarily to transport combat troops."
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Originally, most MBTs relied on steel armour to defend against various threats. As newer threats emerged, however, the defensive systems used by MBTs had to evolve to counter them. One of the first new developments was the use of explosive reactive armour (ERA), developed by Israel in the early 1980s to defend against the shaped-charge warheads of modern anti-tank guided missiles and other such high-explosive anti-tank (HEAT) projectiles. This technology was subsequently adopted and expanded upon by the United States and the Soviet Union.

MBT armour is concentrated at the front of the tank, where it is layered up to 33 centimetres (13 in) thick.
Missiles are cheap and cost-effective anti-tank weapons. ERA can be quickly added to vehicles to increase their survivability. However, the detonation of ERA blocks creates a hazard to any supporting infantry near the tank. Despite this drawback, it is still employed on many Russian MBTs, the latest generation Kontakt-5 being capable of defeating both high-explosive anti-tank (HEAT) and kinetic energy penetrator threats. The Soviets also developed Active Protection Systems (APS) designed to more actively neutralize hostile projectiles before they could even strike the tank, namely the Shtora and Arena systems. The United States has also adopted similar technologies in the form of the Missile Countermeasure Device and as part of the Tank Urban Survival Kit used on M1 Abrams tanks serving in Iraq. The latest Russian MBT, the T-14 Armata, incorporates an AESA radar as part of its Afghanit APS and in conjunction with the rest of its armament, can also intercept aircraft and missiles.
MBTs can also be protected from radar detection by incorporating stealth technology. The T-14 Armata has a turret designed to be harder to detect with radars and thermal sights. Advanced camouflage, like the Russian Nakidka, will also reduce the radar and thermal signatures of a MBT.
Other defensive developments focused on improving the strength of the armour itself; one of the notable advancements coming from the British with the development of Chobham armour in the 1970s. It was first employed on the American M1 Abrams and later the British Challenger 1. Chobham armour uses a lattice of composite and ceramic materials along with metal alloys to defeat incoming threats, and proved highly effective in the conflicts in Iraq in the early 1990s and 2000s; surviving numerous impacts from 1950s, 1960s, and 1970s era rocket-propelled grenades with negligible damage. It is much less efficient against later models of RPGs. For example, the RPG-29 from the 1980s is able to penetrate the frontal hull armour of the Challenger 2.

Almost all modern main battle tanks are equipped with a main gun, also known as the cannon, which serves as the MBTs main weapon, and a coaxial machine gun, also known as the 'coax' which serves as a secondary weapon both controlled and aimed using the tank's fire-control system.
The main cannon serves as the primary armament of a main battle tank and is what makes the tank an effective weapons platform against enemy vehicles, buildings, bunkers, hard cover and allows for long range firing on such targets from several kilometers away. The cannon also gives main battle tanks a great deal of variety in the ammunition they can fire depending on the task at hand, providing fire support capabilities that other armoured fighting vehicles are unable to replicate and enhances the versatility of the MBT. These ammunition types include Armor Piercing, HEAT, HESH, High Explosive, Multi-Purpose, canister, smoke and training rounds, as well as Anti-Tank Guided Missiles.
Since WWII and throughout the Cold War, main battle tanks have seen a marked increase in the calibre of their cannons. Soviet main guns were armed with 85-mm cannons during WWII, with the first Soviet Main battle tank, the T-62, featuring a 115-mm gun, and the T-64 being the first Soviet tank to feature a 125-mm cannon which remained the calibre used in all subsequent Soviet, and now modern Russian MBTs, including the first Russian tank designed since the fall of the USSR, the T-14 Armata. Western tanks also have seen similar large increases in their calibre, with the first British MBT, the Centurion, featuring the 105mm L7 cannon, with its successor, the Chieftain moving to a 120mm L11A5 cannon, with this caliber being used on all subsequent British tanks including the Challenger 1, Challenger 2, and the latest Challenger 3, although the cannon itself changed on the Challenger 2 to the L30A1 and again for the Challenger 3 to the German designed Rh-120, designated L55A1 in British service. The first American MBT, the M48 Patton, was initially equipped with a 90mm cannon, but later models were retrofitted with to a 105mm L7 derivative in 1975. This same caliber was used on the M60 in the form of the M68 tank gun which was also fitted to the original M1 Abrams before being upgraded to the 120mm M256 in 1984 and remains used on the latest variants.

Another trend in MBT main cannons throughout the Cold War was the shift from rifled, to smoothbore cannons. The Soviet Union's first MBT was fitted with the first smoothbore weapon for tanks, the U-5TS, and all subsequent Soviet and Russian tanks have retained the smoothbore design in various iterations of the 2A46 series. Western main battle tank designers first experimented with a smoothbore cannons in the American-West German MBT-70. While the US Army initially wanted to equip the MBT-70 with a 152mm rifled cannon which would function as a gun and missile launcher, German designers advocated using a 120mm smoothbore cannon developed in parallel with the MBT, which eventually was used on the Leopard 2, replacing the 105mm rifled cannon on the outgoing Leopard 1, and the Americans adopted a derivative of the same smoothbore cannon on their M1 Abrams. British MBTs have been outliers in retaining the rifled cannon on their tanks, up to the Challenger 2, however even this has now changed and the latest Challenger 3 is to be equipped with a smoothbore cannon.
The primary reason for moving from rifled to smoothbore is due to the advent of Armor-Piercing Fin-Stabilised Discarding Sabot rounds, APFSDS.
Prior to the use of these rounds, main battle tanks used rifled cannons to spin the projectiles they fired in an effort to prevent tumbling and improve accuracy. These rounds, such as Armour-piercing Discarding Sabot, APDS, which were used to combat enemy armour, spun the sabot which in turn transferred the rotational force to the subcaliber armour piercing dart/rod penetrator contained within it, stabilising it in flight after the sabot discarded. This kinetic energy penetrator, made of a high density material such as depleted uranium, concentrates a high level of kinetic energy over a small surface area, enabling the dart to penetrate heavily armoured targets such as other MBTs, going straight through the armor and into the tank, causing high temperature metal fragments of the target's own armour to sheer off and spall inside the MBT creating deadly shrapnel that can maim or kill some or all of the crew, setting rounds and ammunition in the tank on fire or rupturing fuel tanks and lines. This phenomenon is known as beyond-armour effect, sometimes called behind-armour effects, creating destructive effects inside an armoured target as a result of it being penetrated by the projectile.

With APFSDS rounds, the dart penetrator has stabilising fins integrated into the dart penetrator, keeping it stable in flight and negating the need to spin for stabilisation. By removing the rifling, the pressure in the barrel can be increased, friction from the removal of the rifling grooves removed, which works to increase both the velocity of the rounds fired and the life of the barrel, leading to main battle tanks increasing their range and penetration capabilities and reducing barrel wear. While APDS rounds typically had an effective range of between 1.5 to 2 kilometers APFSDS rounds can be effective up to 4 kilometers. It was also discovered that HEAT rounds fired from MBTs benefited from removing the rifling, providing higher penetration if they do not rotate and spin in flight. APFSDS rounds have since superseded APDS rounds since the removed spin allows for a longer penetrator dart to be encased in the sabot, meaning it can fly further and at higher velocity, improving kinetic energy efficacy in penetrating heavily armoured targets and are now the primary way MBTs destroy these targets, however the basic principle of creating beyond-armour effects through penetrating the target remains the same as with APDS rounds. While tanks with rifled barrels can also fire APFSDS rounds, the act of transferring some of the energy from forward kinetic energy into unnecessary rotational energy decreases the efficacy of the round in penetrating armoured targets.

High Explosive Anti Tank, HEAT, is another anti-armour round used to destroy enemy vehicles, however these are usually ones that do not have as much armour as a MBT, being more lightly armored such as Armoured Personnel Carriers, Infantry Fighting Vehicles and Infantry Mobility Vehicles. HEAT rounds were initially favoured as the primary means of destroying enemy armoured targets by the United States and France up until the introduction of APFSDS ammunition in the 1970s. These rounds remain used however as they are also effective against fortified positions and infantry targets. HEAT rounds use a shaped charge warhead, which converts the chemical energy released by the round exploding the into kinetic energy of a high-velocity metallic jet. When the round detonates, the explosive collapsed a metal liner inward, forming the jet. The leading portion of the jet penetrates the armour of the target, producing fragments and spall inside the target, creating behind-armour effects. Because HEAT rounds do not discard any of their outer jacket, instead carrying the full round and explosive charge to the target, they are far heavier than APDS/APFSDS rounds, weighing approximately 20lbs, more and therefore fly in more of an arc compared to the straight line of the APDS/APFSDS dart penetrator, meaning they cannot be fired as far before accuracy dramatically diminishes, typically up to 1.5 kilometers. While useful against armoured targets, modern MBTs have developed several protective measures against HEAT rounds, most notably explosive reactive armour, ERA, and composite armour construction.
High Explosive, HE, rounds contain several kilograms of explosives, and can sometimes be produced and classified into specific types of HE depending on the round, such as fragmentation, designated as HE-FRAG, or for obstacle reduction, designated as HE-OR. These are fin stabilised rounds providing a slow rate of spin when in flight and are primarily used as general-purpose rounds for use against a variety of targets such as infantry, light skinned vehicles, fortifications, emplaced weapons stations and buildings or as a breach against them. While being relatively ineffective at destroying heavily armoured targets, HE and HE-FRAG rounds can see some success in damaging such targets and producing mobility kills or disabling the armaments or optics of such targets. Some more modern HE-FRAG rounds feature a remote detonator, allowing the round to explode in midair, making it especially effective against infantry targets behind cover, in trenches or spread out in open terrain.

High Explosive Squash Head, HESH, rounds are unique type of anti-armour rounds which seek not to penetrate the armour directly, as is the case with APDS/APFSDS rounds using kinetic energy, but rather detonating on the armour "squashing" the head of the round against it forming a large flat disc-shaped plastic explosive charge pressed onto the outer layer of armour which subsequently explodes when the rear of the round containing the fuse makes contact with it. This explosion generates shockwaves throughout the armour of the target, passing through the armor until reaching the opposite side on the interior of the vehicle. Because the shockwave cannot transmit any further through the armor, it reverses and travels back through to the outer layer of the armor. This causes the inner surface of the armor to flake off, creating spall that is projected into the crew compartment, creating beyond-armour effects without directly penetrating the armour. HESH rounds are spun in order to ensure a predictable and optimal distribution of the explosive plastic filler makes contact with the outer armor of the target. Up until the development of the Challenger 3, the British Army wished to maintain the rifled barrels in their Challenger 2 tanks for this purpose of maintaining compatibility with HESH, however has since moved to adopt a smoothbore cannon and shifted doctrine to be more aligned with NATO partners who do not use HESH rounds and rifled tank barrels.
Canister rounds are a type of anti-personnel rounds designed for the defense of MBTs against large numbers of infantry, breaking up infantry formations at close range, typically up to a few hundred meters, as well as engaging light skinned vehicles and possessing anti-obstacle capabilities. Unlike HEAT and HESH rounds, the canister round has no fuse, rather acts more like a shotgun shell dispersing a conical barrage of hundreds of tungsten balls with the intention of maiming or killing infantry targets, enhancing the survivability of the MBT against infantry targets making the round as much of a defensive round as it is offensive.
Smoke rounds may also be fired by MBTs, however in reality this is something of a misnomer as they are officially white phosphorus rounds. These can be fired from the main gun to create a smokescreen that lasts for several seconds, which can be used to support infantry by providing a blanket of concealing smoke, far larger than what could be generated by hand held smoke grenades issued to infantry. These should not be confused with the smoke grenade launchers that are fitted to most MBTs as a means of defense, as smoke rounds are a round fired from the main cannon of the MBT at a specific target, rather than arrays of smaller smoke grenades launched from the vehicle at fixed points.
In 2025, Rheinmetall's 130 mm smoothbore cannon became the reference gun for multiple European MBT projects, including Leopard 3 and MGCS, reflecting a continental shift beyond NATO-standard 120 mm calibers.
Coaxial machine guns are mounted to the sides of the main cannon and provide additional lethality and versatility to the weaponry of the tank.
The coaxial machine gun serves to allow tank crews to engage soft targets for which the main cannon rounds would be wasteful or ineffective, as the main gun only carries a limited amount of ammunition and can only fire one round before needing to reload, whereas the coaxial machine gun can carry thousands of rounds and provide fully automatic fire. This allows the coaxial machine gun to be an effective weapon against infantry targets, suppressive fire, targets behind light cover, unarmored vehicles and equipment. This can be especially useful in a combined arms application, where the main battle tank, accompanied by friendly infantry forces, provides suppressive fire after making a breakthrough, with Soviet doctrine stating the main battle tanks provide a "curtain [of] fire" over the enemy, pinning them down and allowing infantry forces to advance, as well as useful in point defense of the tank against suspected target locations where continuous fire is needed or where firing the main cannon is not practical.
Historically, a coaxial machine gun mounted to main battle tanks could be used to assist gunners in ranging their targets. The British Centurion MBT was equipped with the dedicated L6A1 ranging gun, coaxially mounted and configured to fire tracer rounds in three round bursts to assist the gunner in ranging the main gun, making the coaxial machine gun a target acquisition tool rather than a secondary weapon, however the advent of modern laser range finding has meant that this use for the coaxial machine gun has been replaced.

Coaxial machineguns are usually variants of the same general purpose machine gun that are issued to infantry, but modified for use inside an armoured fighting vehicle. Barrels are thicker to allow for better cooling inside the vehicle and reduced need for barrel changes inside the tank where doing so may be more difficult. Buttstocks, bipods and iron sights are removed also to save space and because such features are redundant when configured for use as a coaxial machine gun. Barrel shrouds are removed as the gun is not held by the gunner during use. The coaxial makes use of a solenoid connected to the same firing controls as main cannon, meaning the gunner can use the same controller as the main gun and allowing them to toggle between the coax and cannon all on the same controller. The M240C for example is the coaxial machinegun of the US Army and installed in the Abrams tank and is derived from the M240 with the C denoting it is for deployment in vehicles has a charging cable rather than handle, a removed buttstock and thicker barrel. The Soviet/Russian PKT is derived from the PK machine gun adapted for use as a coaxial machine gun in a similar fashion.
Many main battle tanks will also feature a roof mounted machine gun which can move independently of the main turret, either in a fixed arc or a fill 360 degree range, allowing the tank to engage targets on the different directions from where the main cannon and coaxial machine gun are facing. This serves a dual purpose of engaging enemy aircraft due to the higher elevation these roof mounted systems allowed, as well as ground targets as well as suppressive fire and point defense. It is usually intended to be fired by the tank commander, but in some MBTs this weapons station is manned by the loader, who would emerge from their hatch to man the weapon and engage targets. The American M1 Abrams is noted as being a rare example of the gunner, commander and loader each having a weapons system with there being a coaxial machine gun and both commander and loader weapons station.
The idea of having an externally mounted machine gun to main battle tanks can be found as early as WWII, with American main battle tanks being noted in their design and appearance for their addition. However it was not until the early years of the Cold War did Soviet main battle tank designs begin to incorporate it as standard on their new T-54, with the only WWII Soviet tank to employ such a system being the IS-2 heavy tank, mounting a manually operated 12.7mm DShKM heavy machine gun to the commanders hatch.
Modern developments of this roof mounted machine gun have seen it become a Remote Weapons Stations, or RWS, whereby the commander can remain inside the tank to fire the weapon without exposing themselves to hostile fire. This overcomes a significant drawback of these externally mounted systems in that being exposed to hostile fire can render the weapon mount useless, as Russian tank crews serving in Chechnya mentioned it was suicidal to attempt using their T-72s exposed machine gun in urban environments where it would be useful for engaging targets on high buildings. American designers also acknowledged this drawback of externally mounted weapons systems on the Abrams MBT, providing a Transparent Armor Gun Shield to the loader machine gun mount as part of its urban survivability package.

RWS systems, such as the American CROWS are usually heavier caliber rounds than the coaxial machine gun, usually .50 caliber M2 browning compared to the 7.62mm coaxial, although some tanks may use the same caliber as the coaxial system or even be equipped instead with a 40mm grenade launcher, and have their own independent optics and fire control systems with thermal and night vision capabilities, allowing the tank commander independent viewing, which is useful for enhancing the situational awareness of the tank crew, even if the weapon is not fired.
The first Soviet MBT to be equipped with such a system was the T-64, equipped with the ZU-64A remote-controlled anti-aircraft weapons station, however T-72s, designed at the time to be more mass-produced, were not equipped with the remote system, retaining the manually operated systems, however more modern Soviet tanks such as the T-90 reinstated the remote station.
Even more recently, this RWS station has been proposed to be expanded to counter modern threats to tanks, such as counter-UAS capabilities, as well as potential for the RWS system to incorporate anti-tank weaponry.

Performing situational awareness and communicating is one of four primary MBT functions. For situational awareness, the crew can use a circular review system combining augmented reality and artificial Intelligence technologies. These systems use several externally mounted video sensors to transfer a 360º view of the tank's surroundings onto crew helmet-mounted displays or other display systems.
MBTs, like previous models of tanks, move on continuous tracks, which provide adequate mobility over most terrain, including sand and mud. They also enable tanks to climb over most obstacles. MBTs can be made water-tight, so they can even dive into shallow water (5 m (16 ft) with snorkel). However, tracks are not as fast as wheels; the maximum speed of a tank is about 65 km/h (40 mph). The extreme weight of vehicles of this type 40–70 t (39–69 long tons; 44–77 short tons) also limits their speed. They are usually equipped with a 1,200–1,500 hp (890–1,120 kW) engine (more than 25,000 cc (1,526 cu in)), with an operational range near 500 km (310 mi).
The German Army has prioritized mobility in its Leopard 2 which is considered one of the fastest MBTs in existence. The Leopard 2A8 retains the MTU MB 873 Ka-501 engine delivering 1,500 horsepower, paired with enhanced suspension for higher endurance over rough terrain. Ergonomic redesigns, improved climate control, and NBC protection further enhance crew performance in extended combat scenarios.
The MBT is often cumbersome in traffic and frequently obstructs the normal flow of traffic. The tracks can damage some roads after repeated use. Many structures like bridges do not have the load capacity to support an MBT. In the fast pace of combat, it is often impossible to test the sturdiness of these structures. Though appreciated for its excellent off-road characteristics, the MBT can become immobilized in muddy conditions.
The high cost of MBTs can be attributed in part to the high-performance engine-transmission system and to the fire control system. Also, propulsion systems are not produced in high enough quantities to take advantage of economies of scale.
Crew fatigue limits the operational range of MBTs in combat. Reducing the crew to three and relocating all crewmembers from the turret to the hull could provide time to sleep for one off-shift crewmember located in the rear of the hull. In this scenario, crewmembers would rotate shifts regularly and all would require cross-training on all vehicle job functions. Cargo aircraft are instrumental to the timely deployment of MBTs. The absence of sufficient numbers of strategic airlift assets can limit the rate of MBT deployments to the number of aircraft available.
Military planners anticipate that the airlift capability for MBTs will not improve in the future. To date, no helicopter has the capability to lift MBTs. Rail and road are heavily used to move MBTs nearer to the battle, ready to fight in prime condition. Where well maintained roads allow it, wheeled tank transporters can be used.
The task of resupply is usually accomplished with large trucks.

Main battle tanks have internal and external storage space. Internal space is reserved for ammunition. External space enhances independence of logistics and can accommodate extra fuel and some personal equipment of the crew.
Many main battle tanks have a bustle, an extension on the rear of the tank turret usually used for storage of ammunition, often with blow-out panels and separated from the rest of the crew compartment, that serve to protect the tank from being totally destroyed in the event the ammunition is hit, which has become known as the Jack-in-the-box-effect.
Attached to this bustle extension may be an externally mounted bustle rack, where tank crews can store gear and supplies that would be useful when out in the field on operation or exercise, but not essential for operation of the tank and subsequently not needed inside it.
The Israeli Merkava can accommodate crew members displaced from a destroyed vehicle in its ammunition compartment.
Emphasis is placed on selecting and training main battle tank crew members. The crew must perform their tasks faultlessly and harmoniously so commanders select teams taking into consideration personalities and talents.
Modern tank crewmen undergo specialist training in operating their MBT, dependent on the role they are expected to perform in the tank.
Main battle tank crewmen, or as they are often called, tankers, first pass through basic training before moving on to training for their specialty role as a tank crewman, which is a practice that mirrors how WWII era tankers were trained, albeit in a shorter timeframe.
In NATO countries, specialist training is usually at dedicated institutions and establishments such as the American Army Armor School, British Royal Tank Training Regiment and the French Ecole de cavalerie de Saumur, usually along with crewmen of other Armoured Fighting Vehicles, where tankers become trained on their MBT and armoured warfare doctrine and unit tactics, dismounted skills, maintenance and repair of their tank through theoretical classes and exercises. Such schools will be equipped with the MBTs used by that nation for training the crewmen, however these may be older variants of the tank than they will eventually serve on, retained in service for this very purpose, with the German Schule gepanzerte Kampftruppen using older Leopard 2A5 variants of the German Leopard 2 MBT when compared to the frontline Leopard 2A6 and A7 models.
Soviet, and now Russian, main battle tank crewmen are trained in a different manner, instead opting to train tankers in more regional levels throughout different armoured formations rather than a single location school-based model as is more common in NATO countries, often training directly with the unit they will eventually serve in, however tank commanders serving as commissioned officers do attend the dedicated Kazan Higher Tank Command School.
While their role as tank crewmen is a generic term, depending on their role in the tank, crewmen may be trained on their distinct duties they are expected to perform as part of their role. Some militaries train their tank crewmen to only be familiar and proficient in their specific role in the tank, while Western crewmen are trained specifically in with what duties, responsibilities and roles their fellow crewman carry out.

Crewmen assuming the role of gunner for example will be trained and tested on the use of the tanks fire control systems and sighting either in a simulator or real world training tanks, making use of special inert training rounds when conducing live fire training and learning target tracking, acquisition and firing drills.
Specialist driver training variants of tanks exist developed for the purpose of familiarising the crewman assigned as the driver with the control of their tank, as is the case with British Challenger 1 and Challenger 2 and German Leopard 1 and Leopard 2 tanks. Such tanks may see their turret removed and replaced with a larger drivers cab to accommodate for drivers to be observed and receive instruction from trainers as well as to improve visibility with increased driver viewports and mirrors, while maintain the same hull weight and controls to allow trainee drivers to become familiar with the tank and its handling characteristics. Ballasts and mock barrels may also be installed to ensure the tank mimics the same weight and line of sight as its operational counterpart with turret installed.
World War II era main battle tanks had between four and five crew members. During World War II, American, British and German main battle tanks were designed to be crewed by a commander, gunner, driver, loader and a fifth crew member who, depending on the tank model, would usually serve a dual role such as assistant driver and bow gunner or co-loader and radio operator, while Soviet and Italian tanks were designed for a four person crew of commander, gunner, driver and loader.
Modern main battle tanks have been reduced to between three and four crew members where the fifth dual role member has been eliminated entirely, and three person tank crews make use of an autoloader to eliminate the need for the loader role, such as in post World War II Soviet and modern day Russian tank designs, as well as the current French main battle tank, the Leclerc.
Most NATO member countries, and nations that use tanks designed by them, retain the loader crewmember and opt for a four person crew.
Tank crewmen during World War II began to be issued uniforms that differed from other soldiers, focusing on maneuverability and protection from injuries sustained within their tanks, as opposed to on the battlefield, something the uniforms of main battle tank crewmen also have historically been issued with.

Crews tend to carry a more stripped down loadout when compared to infantry, focusing more on maneuverability and protection from noise and hazards from operating within the tank, rather than dangers faced by infantry on the battlefield and adapted for the restricted operating space even the largest main battle tanks afford. Tank crews may be issued body armor, however this was deemed to be ineffective at protecting crews from spall or shock injuries they may sustain while inside the tank and may instead be issued Spall vests, also known as "chicken vests" instead which are better suited for protection against these threats.
Soviet tankers could be identified by their distinctive TSh-4 tanker cap, known as the Shlemofon, iterations of which continue to be worn by modern Russian tank crewmen underneath modern hardshell helmets, as the padding it provided when operating in cramped environments of tanks protected crew from head injuries. German Panzer crews were issued black wool jackets designed to hide grease and oil stains that came from working with their tanks and American crews were issued a cropped jacket for better movement and the Model 1938 tanker helmet.
More modern tanker uniforms focus on fire retardant properties and helmets with integrated communications equipment and noise cancelling technology. Crews operating in especially hot climates such as Iraq and Afghanistan may be issued with cooling vests as part of their tanker uniform in order to better regulate the temperature of the crewmen operating in tanks as, even with air conditioning systems, they can get incredibly hot.

Tank crews may also be issued with different footwear compared to infantry units. Tanker boots are worn by main battle tank crews which prioritise the needs specific to these crews when compared to standard military boots such as superior fire retardant properties, improved air circulation and strap rather than lace up design, preventing laces becoming loose in a cramped environment.
While main battle tank crews are not classed as infantry units and their primary weapon is the tank itself, they are still equipped with personal weapons for any out-of-vehicle operations that may arise such as conducting repairs, field maintenance, area security or abandoning a disabled tank. These weapons are usually different from the service weapons issued to infantry units in that they are usually pistols, personal defense weapons or carbines.
For example, the British L22A2 carbine is issued to Challenger 2 crewmen in place of the L85A2 and L85A3. During World War Two, American Sherman crews were initially issued the M1982 Thompson, later issued instead with the M3 Submachine gun which continued to be issued to M60 crews up to the Gulf War, early Abrams crews were issued the M1911 while modern Abrams crewmen are issued M9, or more recently M17, pistols as well as M4 carbines. German tankers during World War II would be issued pistols such as the Walther Model 8 and Model 9, while modern German Leopard 2 crews are issued with MP7 PDWs or P8 pistols, depending on their role in the tank. Red Army tankers were issued with PPS-43 submachine guns, while Soviet and modern Russian tankers tend to be issued with the AKSU. France issues their latest HK416F in a short barreled version for their tank crews.
The main battle tank fulfills the role the British had once called the "universal tank", filling almost all battlefield roles. They were originally designed in the Cold War to combat other MBTs. The modern light tank supplements the MBT in expeditionary roles and situations where all major threats have been neutralized and excess weight in armour and armament would only hinder mobility and cost more money to operate.
Reconnaissance by MBTs is performed in high-intensity conflicts where reconnaissance by light vehicles would be insufficient due to the necessity to "fight" for information.
In asymmetric warfare, main battle tanks are deployed in small, highly concentrated units. MBTs fire only at targets at close range and instead rely on external support such as unmanned aircraft for long range combat.
Main battle tanks have significantly varied characteristics. Procuring too many varieties can place a burden on tactics, training, support and maintenance.
The MBT has a positive morale effect on the infantry it accompanies. It also instills fear in the opposing force who can often hear and even feel their arrival.

MBT production is increasingly being outsourced to wealthy nations. Countries that are just beginning to produce tanks are having difficulties remaining profitable in an industry that is increasingly becoming more expensive through the sophistication of technology. Even some large-scale producers are seeing declines in production. Even China is divesting many of its MBTs.
The production of main battle tanks is limited to manufacturers that specialize in combat vehicles. Commercial manufacturers of civilian vehicles cannot easily be repurposed as MBT production facilities.
Prices for MBTs have more than tripled from 1943 to 2011, although this pales in comparison with the price increase in fighter aircraft from 1943 to 1975.
MBT models, such as the French AMX-40, Italian OF-40, British Vickers MBT and more recently the Chinese VT-4, and upcoming German Panther KF51 can be developed and marketed almost solely as export vehicles and not used by the producing nations armed forces in large numbers, or at all. Other tanks, such as the Soviet T-54/5 and German Leopard 2, see widespread adoption by both their home nation as well as overseas. Some tank producers, such as Japan and Israel, choose not to market their creations for export. Others have export control laws in place.
Export variants of tanks exist, where a tank that was initially intended to be the fielded by a nation is modified for export. Export variants are usually downgraded versions of domestic tanks, having inferior armor and technology, or modified to prevent them from firing certain types of ammunition. Export variants may also not be newly produced tanks, but rather from surplus stock of existing tanks taken from storage.
This is usually done to control the ownership of the latest technologies used on tanks, both preventing the customer nation from owning it, as well as reducing the risk that an export tank gets captured by an adversary who are unable to assess the full capabilities of the tank due to the fact it does not truly represent the capabilities of the standard non-export model from which it is derived.
Export variants of Soviet military equipment, also known as "Monkey Models", were instances where a Soviet main battle tank used by the Soviet Armed Forces was modified and downgraded for export customers outside the USSR. Modern Russian tanks follow similar trends of using domestic models and downgrading them in several ways for export use, applying the moniker "S" to denote that the tank is an export model and inferior to domestic non-S models. For example the T-90M used by the Russian Armed Forces is sold abroad as the T-90MS, notably carrying three fewer main gun rounds with the Russian T-90M carrying 43 compared to the export T-90MS carrying 40. The MS features a 7.62mm caliber PKT light machine gun remote weapon station compared with the M model which is fitted with the 12.7mm caliber Kord heavy machine gun for its remote weapon station. The MS lacks the latest Arena-M active protection system installed on domestic M models, which also have more Kontakt-5 explosive reactive armor blocks and feature protective netting for the turret ring when compared to the MS.
The American M1 Abrams is also sold to export countries in a more stripped down variant, most notably is the absence of depleted uranium armor on the M1A2S variant of the M1A2 sold to Saudi Arabia.Other Abrams tanks have been equipped with diesel engines for export customers, differing from the standard turbine engine found in US versions of the tank.
In other cases, specialised, but not downgraded, versions of tanks will be produced for export to a specific country. The German Leopard 2 has been modified to meet various national requirements, such as the Canadian Leopard 2A4M CAN and A6 CAN, the Norwegian 2A8 NOR and the Spanish Leopard 2E.
Similarly, some nations may choose to upgrade tanks they import from other nations, featuring domestic elements, or using parts from other tanks. For example the British Sherman Firefly was an American M4 Sherman with a more powerful British-built QF 17-pounder gun fitted in place of the 75mm or 76mm gun. South Africa's current Main Battle Tank, the Olifant, is a heavily upgraded British Centurion tank, swapping the original British Rolls Royce Meteor 4B for the American Continental AV1790.
Tanks can also be licensed build, a practice dating back to even the earliest models of tanks produced during World War I. The first tanks mass-produced by America, the M1917, and Italy, the Fiat 3000, were licensed built copies of the French Renault FT light tank while the first Main Battle Tank to be licensed built was the Indian Vijayanta, a copy of the British Vickers MBT. More recently, the Panzer 87, built by Switzerland for its armed forces, is a licensed built copy of the German Leopard 2, and the T-72 has been licensed built in various nations, even after domestic production ended.
In other instances, countries may use another nations tanks to form the basis of their own tank production, developing the tank into a different one. This differs from licensed built examples in that the tank differs from the original model in significant ways, such as different powerpacks, fire control systems, armament and protection, while licensed built examples are usually one to one copies of the original model. Examples include and the Turkish Altay, based on the South Korean K2 Black Panther, having replaced the South Korean auto loader with a manual loading system, and the Chinese Type 99 based on the T-72 chassis.
As of the mid-2020s, several countries have launched parallel main battle tank (MBT) development programs in response to aging fleets, evolving battlefield threats such as unmanned aerial systems (UAS), and the ongoing war in Ukraine. These programs reflect a broader European Defence Fund (EDF) strategy of maintaining sovereign industrial capabilities and preparing for eventual convergence into a next-generation MBT family.
Key initiatives include:
Pitting a traditional combined armed force trained and equipped to defeat similar military organisations against insurgents reminds one of a pile driver attempting to crush a fly, indefatigably persisting in repeating its efforts.[full citation needed]
Main battle tank.
Beyond Asia's large militaries, the broader proliferation of tanks makes sense given the security needs of states with relatively weaker militaries. Naval and amphibious warfare focused states such as Japan and Indonesia are acquiring new tanks to build capacity in land warfare (urban warfare in Japan's case). Bangladesh, as a developing nation, is acquiring cheaper Chinese MBTs for similar reasons. None of these states expect to use these tanks for an expeditionary purpose, or even against a foreign invader. MBTs can play an important role in maintaining internal security.
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