US MILITARY CYBER WALL_________ US MILITARY 411

M1A1 Abrams
M1A1 on a live fire exercise in Iraq, 2003
Type	Main battle tank
Place of origin	United States
Specifications
Weight	63.0 tonnes (69.5 short tons)
Length	7.92 m (26 ft)
Width	3.64 m (12 ft)
Height	2.43 m (8 ft)
Crew	4 (commander, gunner, loader, driver)
Armour	Chobham, RHA
Primary armament	120 mm M256 Smooth Bore Tank Gun 40 rounds
Secondary armament	1× .50 (12.7 mm) M2 BMG machine gun, 2× M240 7.62 mm machine guns (1 pintle, 1 coaxial)
Engine	AGT-1500 turbine engine, Renk HSWL 354 transmission 1500 hp (1119 kW)
Power/weight	24 hp/tonne
Suspension	torsion bar
Operational range	465 km (288 mi)
Speed	Road: 72 km/h (45 mph) Off-road: 48 km/h (30 mph)

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 U.S. 37th Armor Regiment.

The M1 Abrams replaced the M60 Patton in US service, as well as the M48A5. It would, however, serve alongside the M60A3, which had entered service just two years before (1978) the M1, for over a decade.

The M1 Abrams was designed by Chrysler Defense (in 1979, General Dynamics Land Systems Division purchased Chrysler Defense Division) and is currently produced by General Dynamics Corporation in Lima, Ohio, and first entered US Army service in 1980. An improved version of the M1, the M1A1, was introduced in 1985. The M1A1 has the M256 120 mm smoothbore cannon developed by Rheinmetall AG of Germany for the Leopard 2, improved armor, and a WMD protection system. The M1A2 is a further improvement of the M1A1 with a commander's thermal viewer and weapon station, position navigation equipment, digital data bus and a radio interface unit.

Further upgrades include depleted uranium armor for all variants, a system overhaul that returns all A1s to like-new condition (M1A1 AIM), a digital enhancement package for the A1 (M1A1D), a commonality program to standardize parts between the US Army and the Marine Corps (M1A1HC), and an electronic upgrade for the A2 (M1A2 SEP).

During Operations Desert Shield and Desert Storm and for Bosnia, some M1A1s were modified with armor upgrades. The M1 can be equipped with mine plow and mine roller attachments if needed. The M1 chassis also serves as a basis for the Grizzly combat engineering vehicle and the M104 Wolverine heavy assault bridge.

Over 8,800 M1 and M1A1 tanks have been produced at a cost of $2,350,000-4,300,000 per unit, depending on the variant.

Export variants, with the export armor package and different options (such as multi-fuel diesel engines) of the M1 Abrams are also used by the militaries of:

• Australia (59 M1A1 AIM, to enter service in 2007).
• Egypt (880 M1A1)
• Saudi Arabia (315 M1A2)
• Kuwait (218 M1A2)
• Also tested but not adopted by Sweden, Greece and a number of other nations.

Tankers of the 1st Armored Division drive an M1 Abrams tank through the Taunus Mountains north of Frankfurt during Exercise Ready Crucible on February 14, 2005.

The Abrams is protected by Chobham armor, a type of composite armor formed by multiple layers of steel and ceramics. It may also be fitted with reactive armor if needed (as in the Urban Survival Kit). Fuel and ammunition are in armored compartments with blowout panels to protect the crew from the risk of the tank's own ammunition cooking off if the tank is damaged. Protection against spalling is provided by a Kevlar liner. Beginning in 1988, M1A1 tanks received improved armor packages that incorporated depleted uranium (DU) mesh in their armor at the front of the turret and the front of the hull. Armor reinforced in this manner offers significantly increased resistance towards all types of anti-tank weaponry, but at the expense of adding considerable weight to the tank. The first M1A1 tanks to receive this upgrade were tanks stationed in Germany, since they were the first line of defense against the Soviet Union. US tankers participating in Operation Desert Storm received an emergency program to upgrade their tanks with depleted uranium armor immediately before the onset of the campaign. M1A2 tanks uniformly incorporate depleted uranium armor, and all M1A1 tanks in active service have been upgraded to this standard as well. The strength of the armor is estimated to be about the same as similar western, contemporary main battle tanks such as the Leopard 2. The M1A1/M1A2 can survive multiple hits from the most powerful tank munitions (including 120 mm depleted uranium APFSDS) and anti-tank missiles. In the Persian Gulf War, Abrams tanks survived multiple hits at relatively close ranges from Iraqi T-72's, ATGM's. M829 "Silver Bullet" APFSDS rounds from other M1A1 Abrams were unable to penetrate the front and side armor (even at close ranges) in friendly fire incidents as well as an incident in which another Abrams tried to destroy an Abrams that got stuck in mud and had to be abandoned. In addition to the Abrams' advanced armor, some Abrams, most notably M1A1's of the US Marine Corps, are equipped with a Missile Countermeasure Device that jams the guidance systems of laser-guided anti-tank missiles. This device is mounted on the turret roof in front of the Loader's hatch, and can lead some people to mistake Abrams fitted with these devices for the M1A2 version, since the Commander's Independent Thermal Viewer on the latter is mounted in the same place, though the MCD is box-shaped and fixed in place as opposed to cylindrical and rotating like the CITV.

M1A1 firing

M68A1 rifled gun

The main armament of the original model M1 was the M68A1 105 mm rifled tank gun firing a variety of HEAT, high explosive, white phosphorus (smoke), and a highly efficient and lethal anti-personnel (multiple flechette) round. This gun is a license-built version of the British Royal Ordnance L7 gun. While a reliable weapon, the 105 mm was becoming obsolete in the face of advances in armor technology and was installed as a placeholder on the M1 until the M256 120 mm smoothbore could be completed.

M256 smoothbore gun

U.S. Army Soldier from 1st Battalion, 81st Armor Brigade, 85th Armor Division, sets the sights on the main gun of an M1A1 Abrams in Mosul, Iraq on January 8, 2005.

The main armament of the M1A1 and M1A2 is the M256 120 mm smoothbore gun, designed by Rheinmetall AG of Germany and manufactured under license in the US by General Dynamics Land Systems Division in their plant in Lima, Ohio. It is the same armament carried by the German Leopard 2A5 (L44), and is swappable between tanks with modification, however, the version Leopard 2A6 uses is an improved longer gun (L55). Rounds like the M829A2, which can destroy a T-90 or T-80U with a single shot (provided the target tank lacks the kontakt-5 ERA) at 4000m, and high explosive anti-tank (HEAT) shaped charge rounds such as the M830, the latest version of which (M830A2) incorporates a sophisticated multi-mode electronic sensing fuse and more fragmentation which allows it to be used effectively against both armored vehicles and personnel and low-flying aircraft.

The new M1028 120 mm anti-personnel canister cartridge has been brought into service early for use in the aftermath of the 2003 invasion of Iraq. It contains 1,150 ten-millimetre tungsten shot projectiles which spread from the muzzle to produce a shotgun effect lethal out to 500 m. The tungsten balls can be used to clear enemy dismounts, break up hasty ambush sites in urban areas, clear defiles, stop infantry attacks and counter-attacks, and support friendly infantry assaults by providing cover-by-fire.

In addition to this the new MRM-KE (Mid-Range-Munition Kinetic Energy) is also in development. Essentially a cannon-fired guided round, it has a range of roughly 12 km and uses a KE warhead which is rocket assisted in its final phase of flight. This is intended to be the best penetrator yet, an improvement over the US 3rd generation DU penetrator(estimated penetration 790mm).

U.S. Army M1A2 Abrams tanks maneuver in the streets as they conduct a combat patrol in the city of Tall Afar, Iraq, on February 3, 2005. Note the TAGS shield installed on the loader's M240 machine gun.

The Abrams tank has three machine guns:

1. A .50 cal. (12.7 mm) M2 machine gun in front of the commander's hatch. On the M1, M1IP and M1A1, this gun is on a powered mount and can be fired using a 3× magnification sight, known as the CWS, while the vehicle is buttoned up. On the M1A2, M1A2SEP, this gun is on a flex mount. With the forthcoming TUSK addon kit, an M2 or a Mk 19 grenade launcher can be mounted on the CROWS remote weapons platform (similar to the Protector M151 remote weapon station used on the Stryker family of vehicles).
2. A 7.62 mm (.30 caliber) M240C machine gun in front of the loader's hatch on a skate mount.
3. A 7.62 mm M240C machine gun in a coaxial mount. The coaxial MG is aimed and fired with the computer fire control system used for the main gun.

The turret is fitted with two six-barreled smoke grenade launchers (USMC Abrams use an eight-barreled version). These can create a thick smoke that blocks both vision and thermal imaging, and can also be armed with chaff. The engine is also equipped with a smoke generator that is triggered by the driver. The Abrams also has provisions for storing an M16 rifle inside the crew compartment for when they have to leave the protection of the tank under potentially hostile conditions.

The Abrams is equipped with a ballistic fire-control computer that uses data from a variety of sources, including the thermal or daylight gunner's primary sight (GPS), a laser rangefinder, a crosswind sensor, a pendulum static cant sensor, data on the ammunition type, ammunition temperature, and a muzzle reference sensor (MRS) that determines barrel droop due to gravity and temperature. The fire-control system uses this data to compute a firing solution for the gunner. The ballistic solution generated ensures a hit percentage greater than 95 percent at nominal ranges. Either the commander or gunner can fire the main gun. Additionally, the Commander's Independent Thermal Viewer can be used to locate targets and pass them on for the gunner to engage while the commander scans for new targets.

A US Army M1A1 Abrams is marshaled away from the aircraft, after being offloaded from a US Air Force C-17A Globemaster III at Balad Air Base, Iraq, during Operation Iraqi Freedom.

The M1 Abrams is powered by a 1500 hp (1119 kW) Honeywell AGT1500 (originally made by Lycoming) gas turbine, and a 6 speed (4 forward, 2 reverse) Allison X-1100-3B Hydro-Kinetic Automatic transmission, giving it a governed top speed of 45 mph (72 km/h) on roads, 30 mph (48 km/h) cross-country. With the engine governor removed, speeds of around 60 mph (100 km/h) are possible on an improved surface; however, damage to the drive train (especially to the tracks) and an increased risk of injuries to the crew can occur at speeds above 45 mph. The tank can be fueled with diesel fuel, kerosene, any grade of MOGAS (motor gasoline), or JP-4 or JP-8 jet fuel; the U.S. Army uses JP-8 jet fuel in order to simplify logistics.

The gas turbine propulsion system has proven quite reliable in practice and combat, but its high fuel consumption is a serious logistic issue (starting up the turbine alone consumes 40 liters of fuel). The high speed, high temperature jet exhaust emitted from the rear of M1 Abrams tanks makes it difficult for the infantry to proceed shadowing the tank in urban combat. The turbine is noisy, comparable to a helicopter engine, although the noise character (pitch) is significantly different from a contemporary diesel tank engine. Future US tanks may return to reciprocating engines for propulsion, as 4-stroke diesel engines have proven quite successful in other modern heavy tanks, e.g. the Leopard 2, Challenger 2 and Merkava. The small size, simplicity, power-to-weight ratio, and easy removal/replacement of the turbine powerpack does, however, present significant advantages over any proposed reciprocating replacement.

The Abrams can be carried by the C-5 Galaxy and C-17 Globemaster III. The limited capacity (one combat-ready tank or two transport-ready tanks in a C-5, one combat-ready tank in a C-17) caused serious logistical problems when deploying the tanks for the First Gulf War, though there was enough time for 1,848 tanks to be transported by ship. Tanks shipped in the transport-ready configuration require depot-level maintenance to install a number of sections of armor, and need to be fueled and loaded with ammunition. Tanks shipped in the combat-ready configuration can enter combat immediately.

In World War II, it took a Sherman Tank an average of 17 rounds to destroy an enemy tank 700 meters away. The Abrams, by contrast, can destroy certain enemy tanks by firing, on the move, a single round from 2,000 meters away (Crusade by Rick Atkinson, pg. 251, 1993). As the Abrams entered service in the 1980s, they would operate alongside M60A3 within the United States military, and with other NATO tanks in numerous Cold War exercises. These exercises usually took place in Western Europe, especially West Germany, but also in some other countries like South Korea. During such training, Abrams crews honed their skills against the men and equipment of the Soviet Union. However, by 1990 the USSR had collapsed and the Abrams would have its trial by fire in the Middle East.

Abrams main battle tanks of the 3rd Armored Division move out on a mission during Operation Desert Storm.

The Abrams remained untested in combat until the Gulf War in 1991. A total of 1,848 M1A1s were deployed to Saudi Arabia. The M1A1 was superior to Iraq's Soviet-era T-55 and T-62 tanks, as well as Iraqi assembled Russian T-72s, and locally-produced copies (Asad Babil tank). The T-72s (like most Soviet export designs) lacked night vision and then-modern range finders, though they did have some night fighting tanks with older active infrared systems or floodlights — just not the latest starlight scopes and passive infrared scopes as on the Abrams. Only 18 M1A1s were taken out of service due to battle damage and none of these losses resulted in crew deaths from Iraqi fire. There were only 3 tank crew members wounded beyond doubt by enemy action (see table below).

The M1A1 was capable of making kills at ranges in excess of 4000 m. In friendly fire incidents the front armor and fore side turret armor survived direct APFSDS hits from other M1A1s. This was not the case for the side armor of the hull and the rear armor of the turret, as both areas were penetrated at least in two occasions by DU ammunition during the Battle of Norfolk.

Nearly all sources claim that no Abrams tank has ever been destroyed as a result of fire from an enemy tank, but some have certainly taken some damage which required extensive repair. There is at least one account, reported in the following Gulf War's US Official Assessment (scan), of an Abrams being damaged by three kinetic energy piercing rounds. The DoD report indicates that witnesses in the field claimed it was hit by a T-72. The KE rounds were unable to fully penetrate and stuck in the armor, but the damage was enough to send the tank to a maintenance depot. Presumably the impacts set the storage boxes on fire (see this photo of the disabled M1A1 and the article about the Iraqi T-72s for more details). The tests at the impact point indicate the sabot shells were conventional, since no radiological trace was found there.

M1A1 lost to friendly fire.

On the night of February 26, 1991, four Abrams were disabled in a suspected friendly fire incident by Hellfire missiles fired from AH-64 Apache attack helicopters, with the result of some crew members WIA. The tanks were part of TF 1-37 attacking a large section of Tawakalna Republican Guard Division, their numbers being B-23, C-12, D-24 and C-66. C-12 was definitively hit and penetrated by a friendly DU shot, and there is some evidence that another Iraqi T-72 may have scored a single hit on B-23, besides the alleged Hellfire strike (see Iraqi T-72 article).

Tanks D-24 and C-66 took some casualties as well. Only B-23 became a permanent loss. The DoD's damage assessments state that B-23 was the only M1 with signs of a Hellfire missile found nearby.

Also during Operation Desert Storm, three Abrams of the 24 ID were left behind the enemy lines after a swift attack on Talil airfield, south of Nasiriyah, on February 27. One of them was hit by enemy fire, the two other embedded in mud. The tanks were destroyed by US forces in order to prevent any trophy-claim by the Iraqi Army.

M1A1 Abrams from A Company, Task Force 1st Battalion, 35th Armor Regiment, 2nd Brigade Combat Team, 1st Armored Division, pose for a photo under the "Hands of Victory" in Ceremony Square, Baghdad, Iraq.

Further combat was seen during 2003 when US forces invaded Iraq and deposed the Iraqi leader Saddam Hussein. The campaign saw very similar performance from the tank with no Abrams crew member being lost to hostile fire during the battle in Iraq. The most notable achievement of the M1A2s was the destruction of seven T-72s Lion of Babylon tanks in a point-blank skirmish (less than 50 yards) near Mahmoudiyah, about 18 miles south of Baghdad, with no losses for the American side. However, on October 29, 2003, two soldiers were killed and a third wounded when their tank was disabled by an anti-tank mine, which may have been combined with other explosives to increase its effect. This marked the first time deaths resulted from a hostile-fire assault on the M1 tank from enemy forces. Following lessons learned in Desert Storm, the Abrams and many other US combat vehicles used in the conflict were fitted with Combat Identification Panels to reduce friendly fire incidents. These were fitted on the sides and rear of the turret, with flat panels equipped with a four-cornered 'box' image on either side of the turret front (the latter of which can be seen in the above image). In addition to the Abrams' already-formidable armament, some crews were also issued AT4 shoulder-fired anti-tank rockets under the assumption that they might have to engage heavy armor in tight urban areas where the main gun couldn't be brought to bear.

During the major combat operations in Iraq, Abrams crew members were lost when one tank of the US Army's 3rd Infantry Division, and US Marine Corps troops, drove onto a bridge. The bridge failed, dropping the tank into the Euphrates River, where four Marines drowned.

During an early attack on Baghdad, one M1A1 was disabled by a recoiless rifle round that had penetrated the rear engine housing, and punctured a hole in the right rear fuel cell, causing fuel to leak onto the hot turbine engine. After repeated attempts to extinguish the fire, the decision was made to destroy or remove any sensitive equipment. Oil and .50 caliber rounds were scattered in the interior, the ammunition doors were opened and several thermite grenades ignited inside. Another M1 then fired a HEAT round in order to ensure the destruction of the disabled tank. Unfortunately, the tank was completely disabled but still intact. Later, an AGM-65 Maverick was fired into the tank to finish its destruction. Ironically the tank still appeared to be intact from the exterior.

A destroyed M1A1 Abrams rests in front of a Fedayeen camp just outside of Jaman Al Juburi, Iraq on April 6, 2003.

On November 27, 2004 an Abrams tank was badly damaged and its driver killed from shrapnel wounds when an extremely powerful improvised explosive device (IED) consisting of three M109A6 155 mm shells with a total explosive weight of 34.5 kg detonated next to the tank. The other three crew members were able to escape.

On December 25, 2005 another M1A2 was disabled by a roadside bomb that left the tank burning near central Baghdad, Crew member, Spc. Sergio Gudino, died in the attack.

On June 4, 2006 two out of four soldiers died in Baghdad, Iraq, when an IED detonated near their M1A2.

Some were disabled by Iraqi infantrymen in ambushes employing short-range antitank rockets, such as the Russian RPG-7, during the 2003 invasion. This damage usually corresponds to the tracks of the Abrams. Another one was put out of action when heavy machine gun rounds struck fuel stowed in an external rack, starting a fire that spread to the engine.

M1A2 with TUSK

The Tank Urban Survival Kit, or TUSK, is a series of improvements to the M1 Abrams intended to improve fighting ability in urban environments. Historically, urban and other close battlefields have been the worst place for tanks to fight—a tank's front armor is much stronger than that on the sides, top, or rear, and in an urban environment, attacks can come from any direction, and attackers can get close enough to reliably hit weak points in the tank's armor, or get sufficient elevation to hit the top armor square on.

Armor upgrades include reactive armor on the sides of the tank and slat armor (similar to that on the Stryker) on the rear to protect against rocket-propelled grenades and other shaped charge warheads.

A gun shield and a thermal sight system are added to the loader's top-mounted M240B 7.62 mm machine gun, and a Kongsberg Gruppen Remote Weapon Turret carrying a .50 caliber machine gun (again similar to that used on the Stryker) is in place of the tank commander's original .50 caliber machine gun mount, wherein the commander had to expose himself to fire the weapon manually. An exterior telephone allows supporting infantry to communicate with the tank commander.

The TUSK system is a field-installable kit that allows tanks to be upgraded without needing to be recalled to a maintenance depot.

While the reactive armor may not be needed in most situations in maneuver warfare, items like the rear slat armor, loader's gun shield, infantry phone (which has already seen use on Marine Corps M1A1s as early as 2003), and Kongsberg Remote Weapons Station for the .50 caliber machine gun will be added to the entire M1A2 fleet over time.

In addition to this, a Transparent Armor Gun Shield may also be implemented as part of this kit, as it's already seeing use on some Abrams serving in Iraq.

An M1A1 Abrams tank from 1st Tank Battalion, 1st Marine Division, breaches the obstacle belt with a mine plow during an amphibious assault in 1997.

• XM1 Experimental model; nine test-beds were produced in 1978.
• M1 First production variant. Production began in 1979 and continued to 1985.
  • M1IP (Improvement Production) Produced briefly in 1984 before the M1A1, contained upgrades and reconfigurations.
• M1A1 Production started in 1986 and continued to 1992.
  • M1A1HC (Heavy Common) adding new depleted uranium armor mesh, pressurized NBC system, rear bustle rack for improved stowage of supplies and crew belongings, and M256 120 mm smoothbore cannon.
  • M1A1-D (Digital) A digital upgrade for the M1A1HC, to keep up with M1A2 SEP.
  • M1A1-AIM (Abrams Integrated Management) A program whereby older units are reconditioned to zero hour conditions [3].
  • M1A1 KVT (Krasnovian Variant Tank) M1A1's that have been visually modified to resemble Soviet-made tanks for use at the National Training Center.
• M1A2 (Baseline) Production began in 1992.
• M1A2 SEP (System Enhancment Package) Also with upgraded 3rd generation depleted uranium encased armor with graphite coding.
• M1 Grizzly Engineer Vehicle.
• M1 Panther II Remote Controlled Mine Clearing Vehicle.
• M104 Wolverine Heavy Assault Bridge.
• M1 Panther II Mine Clearing Blade/Roller System.
• M1 Assault Breacher Vehicle.
• M1 Armored Recovery Vehicle. Only a prototype produced.
• TUSK Tank Urban Survival Kit.