M8 Armored Gun System
The M8 Armored Gun System (AGS), sometimes known as the Buford, was an American light tank that was intended to replace the M551A1 Sheridan in the 82nd Airborne Division, and serve as armor support for reconnaissance assets in the 2nd Armored Cavalry Regiment (2nd ACR). The M8 AGS began as a private venture of FMC Corporation, called the Close Combat Vehicle-Light (CCV-L), in 1983. The Army began the Armored Gun System program to develop a mobile gun platform that could be airdropped. By 1992 the program was its top-priority development program. The service  selected FMC's CCV-L over competitive offers from three other teams. The service sought to purchase AGS systems to begin fielding in 1997. The AGS was canceled in 1996 due to budgetary constraints. United Defense LP proposed the AGS for the Mobile Gun System variant of the Interim Armored Vehicle program in 2000, but lost out to the General Motors–General Dynamics LAV III, which was type classified as the Stryker M1128 Mobile Gun System; the MGS system lacked the capability to be airdropped. In 2017, the Army initiated the Mobile Protected Firepower program to acquire a light tank  asset. BAE Systems offered the AGS system to meet this requirement, but it was not selected. Development. In the 1980s, the United States Army began looking for an air-portable replacement for their M551 Sheridan light tanks. Several Army projects to update or replace the Sheridan had proved unsuccessful. After the cancelation of the Army's Mobile Protected Gun System around 1982, the Army decided to equip its light forces with the TOW missile and Mk 19 grenade launcher-armed Humvee in the interim. The MPGS program morphed into the Armored/Assault Gun System. In 1985 the Army Vice Chief  of Staff approved an amended Requirement Operational Capability for the Armored Gun System. The Army Chief of Staff did not lobby for funding the program in Congress however, given its low priority. In May 1986, the Armored Family of Vehicles Task Force was given the lead on the program. In August 1987, the Office of the Secretary of Defense approved the AGS program initiative for 600 vehicles. A joint Army–Marine Corps program was explored. In December, the AGS program was dropped as the $800 million plan was considered unaffordable. Around the same time the Army Chief of Staff  issued a "promissory note" to replace the Sheridan by FY1995. In September 1989, the Armored Gun System Project Manager office was established at TACOM and a marketing survey was distributed to industry. The Army formalized the Armored Gun System program in April 1990 with the issue of a new Requirement Operational Capability document. In addition to being expected to replace the Sheridan in the 3/73rd Armor of the 82nd Airborne Division, it was also expected to serve as armor support for reconnaissance assets in the 2nd Armored Cavalry Regiment. FMC Corporation submitted the Close Combat Vehicle-Light to meet the  AGS requirement. The CCV-L was a private venture of FMC. Three other teams submitted proposals: The bids ranged from a high of $189 million for GDLS—Teledyne and a low of $92 million for Hägglunds. In June 1992, the Army selected the FMC proposal. FMC was awarded $27.7 million to begin phase 1 work, including the production of six test units. The procurement program was valued at $800 million. The Army, believing that the requirement would deter submissions, did not originally require that the AGS be air-droppable by the C-130. Nevertheless, FMC's proposal  claimed that it could achieve this feat. After winning the contract, FMC made several weight-saving changes to the design, including lightening the pallets, in order to meet the C-130's weight limit. In December 1993 report, the Defense Department Inspector General predicted that the AGS would be too heavy for low-velocity airdrop. The report said the AGS did not meet the Army's requirements for air mobility, and recommended delaying low-rate initial production until the airdrop requirement could be met. The Army strongly refuted the Inspector General's report. The Inspector General's concerns were put to  rest in October 1994, when the service successfully airdropped an AGS from a C-130 at an altitude of 1300 feet. Citing cuts in procurement funding, in 1993, the Army cut its planned AGS order from 300 to 233. In 1994, the Army settled on an acquisition target of 237 vehicles. Of these, 123 would go to the 2nd ACR, 58 to the 82nd, and 56 to reserves and training bases. The last 169 AGS systems, to be produced from 1998 to 2002, were to be built without the weight-saving modifications of those destined for the 82nd, which was the  only unit that required an airdroppable AGS system. Six prototypes were built under the designation XM8 AGS. The first of these was rolled out at the United Defense (created by a merger of FMC and BMY) facility in San Jose, California, in April 1994, and arrived at Fort Knox in April 1995. The last of these was delivered in May. United Defense provided five AGS systems to the service's Operational Test Command, which put the vehicle through five months of testing at Fort Pickett. Another prototype underwent survivability testing at Aberdeen Proving Ground. In 1995, the Army explored cutting  the 2nd ACR, which would reduce the Army's buy to 80 AGS for the 82nd Airborne. In May 1995, the National Guard expressed interest in procuring the AGS for the 38th Infantry Division, 35th Infantry Division and 34th Infantry Division in order to help bridge the looming capability gap should the 2nd ACR be eliminated. This proposal was rejected by the service. The M8 was type-classified by the Army in late 1995 The Army approved production of the AGS in October. An initial production run of 26 vehicles with an option for 42 more scheduled to begin in  FY1997. A full production decision would be reached in 1997. Fielding to the 3/73 Armor would begin in 1999. All three squadrons of the 2nd ACR were to be fielded subsequently. With the reduction in the planned buy of AGS systems due to the decision to eliminate the 2nd ACR, the program lost much of its economies of scale. The Army canceled the AGS in January 1996 to free up money for other fledgling programs. The Army estimated killing the program would save the service $1 billion. The service's decision to kill the AGS was met with resistance  from Congress. The Army sought to win support for its decision by the Office of the Secretary of Defense, which would ensure that the service would not have to forfeit unspent funds from the AGS. Proposed revivals. In 1998, the Senate Armed Services Committee proposed using the AGS as a surrogate vehicle to evaluate "strike force experimentation activities" in the 2nd Cavalry Regiment. United Defense LP proposed the AGS for the Mobile Gun System variant of the Interim Armored Vehicle program in 2000. United Defense provided an AGS armored in level 1 and 2 for a platform performance demonstration from  December 1999 to January 2000. The AGS lost out to a variant of the General Motors LAV III, which was type classified as the Stryker M1128 Mobile Gun System. The Government Accounting Office denied UDLP's protest of the award in April 2001. In March 2004, at the 82nd Airborne Division's request, the Army approved the transfer of four production vehicles from United Defense's facility in Pennsylvania, to the 82nd's 17th Cavalry Squad at Fort Bragg in North Carolina. However, in June 2004, this plan was put on hold while the Army determined whether the Mobile Gun  System could meet the 82nd's requirements. An air-drop test of a Stryker weighted to simulate the load of the MGS was conducted in August. Around the same time, the Army identified issues with the air-worthiness of the MGS, among the heavier of the Stryker family. Still more pervasive problems persisted with the autoloader. In January 2005, the Army said it had ruled out fielding the AGS, saying the system lacked spare parts that would be required to maintain the vehicle for any significant length of time. The Army doubled down on its commitment to fielding the MGS , which it said it could begin fielding in summer 2006. United Defense sought overseas customers, without success. In 1996, United Defense was planning on shipping an AGS prototype to Taiwan. In 1996, they had partnered with FMC Nurol to offer the AGS to the Turkish Land Forces, which was seeking a main battle tank. By 1998, Canada, Germany, Malaysia and Singapore had expressed interest in the tank. In 2015, the U.S. Army articulated a requirement for a Mobile Protected Firepower system to replace the Mobile Gun System. In 2017, the Army formalized its requirements with a request for proposals. The  MPF was defined as an air-transportable light tank to assist infantry brigades in forced entry operations. The Army sought to buy 504 MPF systems. Requirements called for a tracked vehicle armed with a 105 mm or 120 mm caliber cannon, which would not need to be air-droppable. BAE Systems (which bought United Defense in 2005) entered a modernized AGS into the MPF competition. In 2018, the Army selected bids from GDLS and BAE to build 12 prototypes each. BAE began delivering the vehicles to the Army in December 2020. In February 2022, BAE was eliminated from the competition  due to noncompliance issues, leaving the General Dynamics Griffin as the only MPF entry. Design. The basic hull of the AGS is made of welded 5083 aluminium alloy, with a modular armoring system that allows the vehicle to be equipped according to requirements. Aluminum was chosen instead of steel in order to reduce the weight of the vehicle. The weight limit requirement for the vehicle was driven by the airdrop requirement. Protection. Modular armor levels: The crew is compartmentalized from the ammunition magazine by a firewall. An NBC overpressure system is equipped (a requirement for radiation hardening was omitted). Mobility . Power is provided by a Detroit Diesel 6V-92TA 6-cylinder multifuel diesel engine developing 550 hp at 2400 rpm. This had 65% commonality with that of the Heavy Expanded Mobility Tactical Truck (HEMTT). The AGS's power-to-weight ratio was greater than the M1A1 Abrams. The top speed is governor-limited to 45 miles per hour. The fuel capacity is 150 gallons, giving the AGS a projected range of 300 miles. The General Electric HMPT-500 transmission is also used by the Bradley Fighting Vehicle. Mounted on two tracks, the powerpack slides out for maintenance, and can be run while  it sits on the tracks at the rear of the vehicle. An auxiliary power unit was considered, but ultimately omitted from the final design to save weight. The Army required two variants of the AGS. One capable of the low-velocity airdrop from the C-17 Globemaster III (intended for the 82nd Airborne), and a heavier variant with roll-on/roll-off capability from the C-5 Galaxy, C-17, C-141 Starlifter and C-130 Hercules. In 1990, the Army had demoted the requirement for LAPES (low-altitude parachute-extraction system) from a required capability to a desired one. After winning the AGS contract , FMC further whittled down the weight of the AGS in order make the tank light enough for low-velocity airdrop from a C-130. Level II and III armor packages can be airdropped separately from the AGS and installed in the field in under three hours. All versions are air-transportable by C-130, C-141, C-17 and C-5 (one, two, three and five systems respectively). For low-velocity airdrop, up to 10 rounds of 105 mm ammunition can be carried in ready capacity. A 1993 TRADOC study called for modifying 53 HEMTTs as Contingency Force Recovery Vehicles to assist with recovering the  AGS. Firepower. The AGS is armed with the Watervliet Arsenal XM35 rifled autoloading 105 mm caliber soft-recoil tank gun with an M240 7.62 mm caliber machine gun mounted coaxially. The XM35 was about lighter than the M68 used on the M60 tank. The XM35 fires all NATO standard 105 mm ammunition in inventory. The XM35 has a rate of fire of approximately 12 rounds per minute, with a ready capacity of 21 rounds and 9 more in hull stowage. The Computing Devices Canada fire-control system is the same used in the Challenger 2. The gun is fully stabilized . Gun depression is −10 degrees, except where limited over the rear arc. The CCVL was originally armed with an M68A1, and held 19 ready rounds plus 24 in storage The autoloader is fed by a rotating 21-round magazine. The gunner selects the type of ammunition to be fired and the computer rotates the magazine to select the correct round accordingly. After firing, the gun returns to zero degrees elevation. The autoloader extracts the spent shell casing from the breech, then ejects it out of the turret through the same port used to load the autoloader. Once the autoloader has  loaded the next round, the gun returns to the elevation of the last target. If the autoloader is disabled, the crew can load the AGS at a rate of three rounds per minute. A Browning M2 12.7 mm (.50) caliber heavy machine gun is mounted in a manually operated pintle on the commander's hatch. Other possible weapons were a M240 7.62 mm caliber machine gun or an MK 19 40 mm grenade launcher. Two eight-barrel smoke grenade launchers were also mounted. The CCVL specified a commander's independent thermal viewer, but was later eliminated to save weight. Miscellany . The AGS has a 1553 data bus. A single technology demonstrator built by United Defense and demonstrated in 2003, incorporating a 120mm smoothbore cannon fitted with an autoloader. In 1994, Loral Vought Systems was awarded a contract to integrate LOSAT on to an M8 AGS hull. BAE Systems entered an updated variant of the M8 in the U.S. Army Mobile Protected Firepower program.