Early Chieftains and some later modified tanks mount the .50 Cal M2HB machine gun over the main gun as a ranging gun.
Iran and Kuwait retained the .50 Cal MG.
A HESH round is available for the main gun. The round is used for anti-tank chemical-energy (CE) antiarmor missions, and for HE
effects against personnel and materiel.
The Iranians claim to employ a snorkel system on Chieftain, for fording to 5 meters depth.
A variety of fire control systems and thermal sights are available for Chieftain. 324 Chieftains have been upgraded with the
Barr and Stroud TOGS thermal sight system. The 1R26 thermal camera can be used with the 1R18 thermal night sight. It has wide
(13.6") and narrow (4.75") fields of view, and is compatible with TOGS format. GEC Sensors offers a long list of sights
including: Multisensors Platform, Tank Thermal Sensor, and SS100/110 thermal night sight. Marconi, Nanoquest, and Pilkington offer
day and night sights for the Chieftain.
Charm Armament upgrade program, with the 120-mm L30 gun incorporated in Challenger 1, is available for Chieftain modification programs.
- Chieftain Mk 5
- Final production variant, with a new engine and NBC system, modified auxiliary weapons and
sights. Mk 6-11 are upgrades to earlier models, with addition of IFCS. Mk 12 added ROMOR (aka: Stillbrew) spaced armor boxes. Mk 11
and Mk 12 have Thermal Observation and Gunnery Sight (TOGS).
- Khalid/Shir 1
- Jordanian variant which has chassis, turret and weaponry of the Chieftain, but which incorporates engine and running gear upgrades of Challenger I. The fire control has seen a number of improvements, including a new ballistic computer.
- FV4204 ARV
- Armored Recovery Vehicle derivative.
- FV4205 AVLB
- Armored Vehicle-Launched Bridge derivative.
Other support vehicles developed from the tank include dozer, mineclearer, air defense and 155-mm SP artillery systems.
