The M1 Abrams () is a third-generation American main battle tank designed by Chrysler Defense (now General Dynamics Land Systems) and named for General Creighton Abrams. It was officially standardized as TANK, COMBAT, FULL TRACKED, 105MM, M1 ABRAMS (NSN 2350-01-061-2445) on June 15, 1978. Conceived for modern armored ground warfare and now one of the heaviest tanks in service at nearly , it introduced several modern technologies to US armored forces, 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 tank. There are three main operational Abrams versions, the M1, M1A1, and M1A2, with each new iteration seeing improvements in armament, protection, and electronics. Extensive improvements have been implemented to the latest formerly designated M1A2 System Enhancement Package version 3 or SEPv3 and M1A2 SEPv4, respectively versions such as improved composite armor, better optics, digital systems and ammunition. The Abrams was to be replaced in U.S. Army service by the XM1202 Mounted Combat System, but since that project was cancelled, the Army has opted to continue maintaining and operating the M1 series for the foreseeable future by upgrading with improved optics, armor, and firepower. The M1 Abrams entered service in 1980 and serves as the main battle tank of the United States Army and formerly of the United States Marine Corps (USMC). The export version is used by the armies of Egypt, Kuwait, Saudi Arabia, Australia, Poland and Iraq. The Abrams was first used in combat in the Persian Gulf War and has seen combat in both the War in Afghanistan and Iraq War under U.S. service, while Iraqi Abrams tanks have seen action in the war against Islamic State and have seen use by Saudi Arabia during the Yemeni Civil War. History Previous developments Through the 1960s the US Army and West German Army had collaborated on a single design that would replace both the M60 tank and the Leopard 1. The overall goal was to have a single new design with improved firepower to handle new Soviet tanks like the T-62, while providing improved protection against the