The M1 Abrams main battle tank is the principal combat tank of the United States Army and the United States Marine Corps, with three main versions being deployed starting in 1980: the '''M1''', '''M1A1''', and '''M1A2'''. The latest versions of the M1A2 have a new armor and electronics package. It is named after General Creighton Abrams, former Army Chief of Staff and commander of the Army's 37th Armored Regiment.
The M1 Abrams MBT was developed by the Chrysler Corporation (now General Dynamics Land Systems Division) with the first prototype being completed in 1976, The first production model, the M1, was armed with the same M68 105mm rifled gun as was fitted to the M60. Later production machines would have increased armor protection.
The M1A1 which appeared in 1985 incorporated many improvements including additional armor, better NBC measures and an uprated suspension. This model also saw the main armament switched to a 120mm Rheinmetall smoothbore gun.
The final version, the M1A2. would incorporate all of the improvements made to the M1A1 plus the addition of a commander's independent thermal viewer.
All versions of the M1 Abrams have a computerized fire control system and stabilized sights for the main armament which allows the gun to be accurately fired whilst the tank is on the move. The M1 Abrams is powered by a 1,500 hp Textron Lycoming AGT gas turbine coupled to an Allison Transmission X-1100-3B automatic transmission.
Anniston Army Depot is the only depot capable of performing maintenance on heavy-tracked combat vehicles such as the M1, and is designated as the Center of Technical Excellence for the M1 Abrams Tank.