Short answers, pulled from the story.
The British Chieftain tank was the first tank to be designated a main battle tank, redesigned during its development in the 1950s to combine heavy firepower, strong armor, and medium-tank mobility in a single vehicle.
Modern MBT armor layers multiple materials including ceramics, composites, and metal alloys. Chobham armor, developed by Britain in the 1970s, uses a lattice of composite and ceramic materials and proved effective against rocket-propelled grenades from the 1950s through 1970s. Explosive reactive armor, developed by Israel in the early 1980s, adds blocks that detonate to defeat shaped-charge warheads. MBT armor is concentrated at the front and can be up to 33 cm thick.
MBT main guns generally run between 100 mm and 125 mm caliber. In 2025, Rheinmetall's 130 mm smoothbore cannon became the reference gun for multiple European MBT projects including Leopard 3 and the Main Ground Combat System, marking a shift beyond the NATO-standard 120 mm caliber.
Modern main battle tanks carry three or four crew members, reduced from the four or five of World War II-era designs. Tanks equipped with an autoloader, such as the French Leclerc and Russian T-64, T-72, T-80, T-84, T-90, and T-14, operate with three crew members. Most NATO member countries retain a human loader and use a four-person crew.
The Main Ground Combat System is a Franco-German project formally launched in 2017, intended to replace the Leopard 2 and Leclerc tanks by 2040. The MGCS Project Company was formed in 2025 by KNDS, Rheinmetall, and Thales as the industrial prime contractor. The system is planned to include a manned MBT, robotic wingmen, and integrated counter-drone and AI command layers.
The maximum speed of a main battle tank is approximately 65 km/h. MBTs typically weigh 40-70 tonnes and are equipped with engines of 1,200-1,500 horsepower producing more than 25,000 cc displacement, with an operational range near 500 km. The Leopard 2A8 retains the MTU MB 873 Ka-501 engine delivering 1,500 horsepower.