Tank

: This article is about armoured fighting vehicles. For other meanings, see Tank (disambiguation).

Weapons

The main weapon of any modern tank is a single gun. Tank guns are among the largest calibre weapons in use on land, with only a few artillery weapons being larger. Although the calibre has not changed substantially since the end of the Second World War, modern guns are technologically superior. The current common sizes are 120-mm calibre for Western tanks and 125-mm for Eastern (Soviet and Chinese legacy) tanks. Tank guns have fired many types of rounds, but their current use is commonly limited to kinetic energy (KE) penetrators and high explosive (HE) rounds. Some tanks can fire missiles through the gun. Smoothbore (rather than rifled) guns are the dominant type of gun today. The British Army and the Indian Army are now the only ones to field main battle tanks with rifled guns.

Related Topics:
Gun - Calibre - Tank gun - Kinetic energy - Penetrator - High explosive

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Modern tank guns are generally fitted with thermal jackets which reduce the effect of uneven temperature or cooling of the barrel. Eg if it were to rain on a tank barrel the top would cool faster than the bottom, or a breeze on the left might cause the left side to cool faster then the right. This uneven cooling will cause the barrel to bend slightly and will effect long range accuracy. The thermal jacket reduces this uneven cooling.

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Usually, tanks carry other armament for short range defence against infantry or targets where the use of the main weapon would be ineffective or wasteful. Typically, this is a small calibre (7.62 to 12.7 mm) machine gun mounted coaxially with the main gun. However, a couple of French tanks such as the AMX-30 and AMX-40 carry a coaxial 20-mm cannon that has a high rate of fire and can destroy lightly armoured vehicles. Additionally, many tanks carry a roof-mounted or commander's cupola machine gun for close-in ground or limited air defence.

Related Topics:
Machine gun - Coaxial - AMX-30 - Cannon

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The 12.7-mm and 14.5-mm machine guns commonly carried on US and Russian tanks are also capable of destroying light armoured vehicles, such as APCs and possible IFVs at close range.

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Some tanks have been adapted to specialised roles and have had unusual main armaments such as flame-throwers. These specialised weapons are now usually mounted on the chassis of an armoured personnel carrier.

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Fire control

Historically, tank weapons were aimed through simple optical sights and laid onto target by hand, with windage estimated or assisted with the reticule. Range-finding was initially estimated, then estimated with the aid of the reticule (which use the measurement of angles, measured in the reticule of known sized objects as a method for range finding), which was later supplemented with stereoscopic optical rangefinders, which remained the standard until the introduction of laser rangefinder. Consequently, accuracy was limited at long range and made concurrent movement and shooting largely impossible.

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Modern MBTs and upgraded MBTs use a laser range-finder but optical and reticule range-finders are still in use in older and less sophisticated vehicles. Modern tanks have a variety of sophisticated systems to make them more accurate. Gyroscopes are used to stabilise the main weapon; laser range-finders are used to measure the range to the target; computers calculate the appropriate elevation and aim-point, taking into account many factors such as wind speed, air temperature, humidity, the temperature of the gun, the speed of the target (calculated by taking at least two sightings of the target with the range-finder), the speed of the tank, the bend of the barrel, and the wear of the barrel. Night and infrared vision equipment is also commonly included. Laser target designators may also be used to illuminate targets for guided munitions. As a result modern tanks can fire reasonably accurately while moving.

Related Topics:
Systems - Gyroscope - Laser - Range-finder - Computer - Elevation - Night - Infrared - Laser target designator - Guided munition

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Ammunition

There are several types of ammunition designed to defeat armour, including HESH (High Explosive Squash Head), HEAT (High Explosive Anti-Tank), APDS/APFSDS (Discarding Sabot designs). Non-KE-penetrator rounds have greater accuracy when fired from rifled guns, but can also be fin-stabilised in order to work with smoothbore guns.

Related Topics:
HESH - HEAT - APFSDS - Rifle

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Some tanks, including the M551 Sheridan, T-72, T-64, T-80, T-90, T-84, and PT-91 can fire ATGMs (AntiTank Guided Missiles) through their gun barrel. This functionality extends the effective combat range of the tank beyond the range afforded by conventional shells. It also provides the tank with a useful weapon against slow, low-flying airborne targets like helicopters. The United States has abandoned this concept, phasing the M551 and M60A2 out of their forces, but CIS countries continue to employ gun-missile systems in their main battle tanks.

Related Topics:
M551 Sheridan - T-72 - T-64 - T-80 - T-90 - T-84 - PT-91 - ATGM - CIS

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