
The Challenger 2, firing its 120 mm L30 gun, produced by the Royal Ordnance division of British Aerospace Defence Ltd at Nottingham, UK. Challenger 2 is equipped with an L30, 120 mm rifled tank gun from the Royal Ordnance division of British Aerospace Defence Ltd at Nottingham, UK. The L30 construction incorporates a chromium lining which provides a harder and smoother internal surface. The chromium lining gives increased velocity and therefore penetration power to the round, greater precision and reduced wear on the barrel. The gun is made from electro-slag refined steel (ESR) and is insulated with a thermal sleeve. The gun is fitted with a muzzle reference system and fume extraction to remove the gasses from the barrel. The turret is capable of 360 degree rotation and the weapon elevation range is from -10 to +20 degrees.
The target engagement sequence has been designed for simplicity of operation in battlefield conditions. The same engagement sequence is followed for static and moving targets in daylight or by night. The gunner or the commander aligns an aiming mark on the target, presses the laser rangefinder button and then presses the fire button.
The 120 mm L30 gun fires all current 120 mm ammunition. There is capacity for 50 projectiles, which can be a mix of armour piercing fin stabilized discarding sabot (APFSDS), high explosive squash head (HESH) or smoke rounds. The L30 gun can also fire the Depleted Uranium (DU) round with a stick charge propellant. Depleted Uranium has a density approximately two and a half times higher than that of steel and the mass of the DU projectile provides high penetration characteristics. The first depleted uranium round, the L30, is part of the Charm 1 gun, charge and projectile system. A Charm 3 system is under development in which the depleted uranium projectile has a higher length to diameter aspect ratio for increased penetration performance. The ammunition, being of the separate projectile and charge loading type, allows the explosive ammunition to be stowed below the turret ring. Armoured bins provide the stowage for the charges.
The gun control is provided by an all-electric gun control and stabilization system from GEC Marconi Radar and Defence Systems of Leicester, UK. The Challenger 2 is also equipped with a McDonnell Douglas 7.62 mm chain gun, which is located to the left of the main tank gun. The loader seated on the left hand side has a 7.62 mm GPMG anti-air machine gun, type L37A2, mounted on the cupola.
On each side of the front of the turret are five L8 smoke grenade dischargers, from the Helio Mirror Company of Kent, UK. The Challenger 2 can also set a smoke screen by the injection of diesel fuel into the engine exhausts.
The Challenger 2 is equipped with a Military Standard 1553 data bus. The fire control computer is a digital computer from Computing Devices Company of Ontario, Canada. The digital CDC computer has capacity for additional systems, for example a Battlefield Information Control System, and navigation and training systems.