The M1 Abrams is a third-generation American main battle tank designed by Chrysler Defense. Conceived for modern armored ground warfare and now one of the heaviest tanks in service at nearly 62 metric tons, it introduced several innovative features, including a multifuel turbine engine, sophisticated Chobham composite armor, a computer fire control system, separate ammunition storage in a blow-out compartment, and NBC protection for crew safety. Initial models of the M1 were armed with a licensed-produced 105 mm Royal Ordnance L7 gun, while later variants feature a licensed Rheinmetall 120 mm L/44.
The M1 Abrams was developed from the failure of the MBT-70 project to replace the obsolescent M60 Patton. There are three main operational Abrams versions, the M1, M1A1, and M1A2, with each new iteration seeing improvements in armament, protection, and electronics. The M1 Abrams entered service in 1980 and currently serves as the main battle tank of the United States Army and Marine Corps.
M1A1:Production started in 1985 and continued to 1992, pressurized NBC system, rear bustle rack for improved stowage of supplies and crew belongings, redesigned blow-off panels and M256 120 mm smoothbore cannon (4,976 built for the U.S. Army, 221 for USMC, 59 M1A1 AIM SA sold to Australia).