M1 Abrams

• 1. Origins And Development History

  ›

  In 1963, the U.S. Army and West German Bundeswehr began a joint project to create a main battle tank known as the MBT-70. This collaboration aimed to improve interoperability between NATO partners but quickly became mired in cultural differences and design disagreements. The United States team was led by General Motors while Germany relied on a consortium of firms. By 1969, the unit cost had grown to approach $1 million per tank, many times the original estimate. Congress canceled the XM803 austere version in December 1971 after failing to allay concerns about the tank's cost and reliability.

  The Army restarted the program in January 1972 under Major General William Desobry with the Main Battle Tank Task Force. In spring 1972, Desobry learned of British Burlington armor which performed exceptionally against shaped charges like HEAT rounds. He convinced the Army to incorporate this new technology into the next design. To utilize Burlington armor effectively, engineers needed to build protection around two feet thick compared to the four inches found on the M60. General Creighton Abrams set the weight limit at 55 tons, abandoning earlier goals to keep it lighter.

  Chrysler Defense and General Motors submitted proposals in May 1973 armed with the 105 mm M68 gun. Chrysler chose a Lycoming AGT1500 gas turbine engine rated at 1,500 hp while GM used a diesel engine. Prototypes delivered in 1976 showed that the GM design offered better armor and fire control systems. However, the Chrysler gas turbine consumed much more fuel than expected during testing. The decision to choose the GM design was largely complete by spring 1976 due to overall performance and lower costs of $208 million versus $221 million for Chrysler.

  Defense Secretary Donald Rumsfeld announced a four-month delay in July 1976 to require a turbine engine. This political decision gave the award to Chrysler since they were the only contractor with a working gas turbine. In November 1976, the Defense Department awarded the $4.9 billion development contract to Chrysler. Production started in February 1978 with eleven preproduction models built at Detroit Arsenal Tank Plant. Quality problems emerged quickly including thrown tracks caused by miscalibrated tension gauges and debris ingestion into engines due to poorly fitting air filters.

• 2. Evolution Of Variants And Upgrades

  ›

  Low rate initial production began in May 1979 with the original M1 model entering U.S. Army service in 1980. A total of 3,273 M1 Abrams tanks were produced between 1979 and 1985. These early vehicles featured Chobham composite armor consisting of ceramic blocks set in resin between layers of conventional armor. The front hull armor provided protection estimated at 350 mm against APFSDS rounds and 700 mm against HEAT warheads according to military historian Steven Zaloga.

  The M1A1 variant entered production starting October 1988 with depleted uranium armor added to the turret backing plate. This upgrade increased weight significantly as depleted uranium is 1.7 times denser than lead. About 5,000 M1A1 tanks were produced from 1986 to 1992 featuring the M256 120 mm smoothbore cannon manufactured under license by Watervliet Arsenal. Production costs reached approximately $4.3 million per unit for both M1 and M1A1 models combined.

  Further improvements came with the M1A2 System Enhancement Package which added digital maps and FBCB2 Linux communications capabilities. The M1A2 SEPv2 included Common Remotely Operated Weapon Station support and better interfaces. Depleted uranium armor was standardized across all variants after the M1A1HA designation. The M1A2 SEPv3 increased line-of-sight thickness on turret and hull front armor though total protection figures remain classified.

  In 2018, the Army ordered 135 tanks rebuilt to new standards with employment rising to over 500 workers at Lima Army Tank Plant. By March 2023, the U.S. Army had a stated goal of procuring 2,204 M1A2 SEPv3 tanks with funds already committed for 2,093 units. This variant became the standard issue tank for the U.S. Army and National Guard as of that date.

• 3. Combat Performance In The Gulf War

  ›

  The first Abrams tanks arrived in Saudi Arabia in August 1990 during Operation Desert Shield buildup. All but two battalions of 105 mm gun Abrams tanks were replaced by M1A1 models prior to the American invasion in January 1991. The U.S. Army deployed 1,956 M1A1s including 733 standard models and 1,233 heavy armor versions to participate in the liberation of Kuwait. The Marine Corps contributed 353 tanks with 76 being M1A1 variants.

  During Operation Desert Storm in 1991, no M1 tanks were lost to enemy fire directly. Three Abrams tanks were left behind enemy lines after an attack on Talil airfield south of Nasiriyah on February 27. One was hit by enemy fire while two others became embedded in mud. Task force commanders destroyed these vehicles by firing rounds into them to prevent capture. A total of 23 M1A1s were damaged or destroyed throughout the war with seven lost to friendly fire and two intentionally destroyed.

  M1A1 tanks could engage targets at ranges exceeding 4,000 meters which proved decisive against Soviet-designed Iraqi T-72s. Effective range of main guns on Iraqi tanks remained under 2,000 meters meaning Abrams crews could strike first. Front armor and fore side turret armor survived direct hits from other M1A1s during friendly fire incidents. Side hull and rear turret areas were penetrated on at least two occasions by unintentional strikes using depleted uranium ammunition during the Battle of Norfolk.

• 4. Adaptations For Urban Warfare

  ›

  Vulnerabilities exposed during urban combat in Iraq led to the Tank Urban Survival Kit modifications issued starting in 2006. Armor upgrades included reactive armor on tank sides and slat armor on the rear to protect against rocket-propelled grenades. ARAT I consisted of 32 XM19 reactive armor boxes added to tank sides while ARAT II used rounded XM32 tiles mounted over top.

  General Dynamics Land Systems received a U.S. Army order for 505 Tank Urban Survivability Kits under a $45 million contract in August 2006. Deliveries were expected to complete by April 2009. The kit added a transparent gun shield and thermal sight system to the loader's top-mounted machine gun. A Kongsberg Gruppen Remote Weapon Turret replaced the commander's original mount allowing remote operation of a 12.7 mm machine gun.

  In December 2006, the Army added Counter Improvised Explosive Device enhancements awarding GDLS an $11.3 million contract. By May 2008, reports indicated a U.S. M1 tank had been damaged in Iraq by Soviet-made RPG-29 Vampir warheads capable of penetrating explosive reactive armor. Insurgent fire disabled approximately 80 tanks by March 2005 with 63 shipped back to the U.S. for repairs.

• 5. Global Export And Modern Conflicts

  ›

  Between 2010 and 2012, the U.S. supplied 140 refurbished M1A1 Abrams tanks to Iraq. During three months starting June 2014, about one-third of Iraqi Army M1 tanks were damaged or destroyed by ISIL forces. Some tanks were captured by opposing groups leaving only 40 operational units by December 2014. The U.S. Department of State approved sales of another 175 Abrams to Iraq that same month.

  Saudi Arabia deployed M1A2s against Houthi rebels during the 2015 Yemeni Civil War. In August 2016, the U.S. approved selling up to 153 more tanks including 20 battle damage replacements suggesting some Saudi tanks had been destroyed or severely damaged. Ukraine received 31 M1A2 variants beginning September 2023 as part of a larger aid package announced by President Joe Biden in January 2023.

  In February 2024, an M1A1 was reported lost in Ukraine after blowout panels on ammo bins activated indicating ammunition cooked off. The tank was destroyed by a FPV Piranha 10 quadcopter drone. By April 2024, Pentagon officials stated Ukrainian Abrams had been withdrawn from frontline service due to hunter killer drones making operations too difficult. Australia transferred 49 recently retired M1A1 tanks to Ukraine starting October 2024.

• 6. Engineering And Armament Systems

  ›

  The original M1 model featured the M68A1 105 mm rifled gun firing armor-piercing fin-stabilized discarding sabot rounds. The tank could carry 55 rounds with 44 stored in turret blowout compartment and rest in hull stowage. Non-combustible empty cartridge cases accumulated on turret floor after firing before being ejected by loader. Later models transitioned to the M256 120 mm smoothbore gun designed by Rheinmetall AG and manufactured under license at Watervliet Arsenal New York.

  Depleted uranium M829 rounds became primary APFSDS ammunition for the M256 gun. Four variants of this round have been designed including M829A1 Silver Bullet which saw widespread service in Gulf War against Iraqi T-72s. The M829A3 introduced in 2002 improved effectiveness against next-generation ERA equipped tanks. Development continues with M829A4 currently entering production featuring data-link capability.

  Fire control systems compute ballistic solutions updated 30 times per second using laser rangefinders crosswind sensors pendulum static cant sensors and muzzle reference systems. The Gunner's Auxiliary Sight allows manual aiming if primary systems fail. Commander Independent Thermal Viewer enables locating targets while scanning for new ones. Ballistic solution ensures hit percentage greater than 95 percent at nominal ranges.