M1128 Mobile Gun System

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M1128 Mobile Gun System
Exercise Allied Spirit I, Day 5 150117-A-EM105-337.jpg
A M1128 Mobile Gun System during a training exercise in 2015
TypeAssault gun
Armored fighting vehicle
Place of originUnited States
Service history
WarsIraq War[1] War in Afghanistan
Production history
DesignerGM Defense of Canada and General Dynamics Land Systems
ManufacturerGeneral Dynamics Land Systems[2]
No. built142[2]
Mass18.77 tonnes (20.69 short tons; 18.47 long tons)
Length6.95 m (22.92 ft)
Width2.72 m (8.97 ft)
Height>2.64 m (>8.72 ft)[3]

Armor14.5 mm resistant[4]
M68A1E4 105 mm cannon
M2 .50 caliber machine gun; M240C coaxial machine gun; 2, M6 smoke grenade launchers
EngineCaterpillar C7 turbo diesel
260 kW (350 hp)
Power/weight18.65 hp/ton
TransmissionAutomatic 6 forward, 1 reverse
Suspension8×8 wheeled
Ground clearance15 in (38 cm)
Fuel capacity56 gallons (212 liters)
330 miles (528 km)
Maximum speed 60 mph (96 km/h)

The M1128 Mobile Gun System is an eight-wheeled armored car of the Stryker armored fighting vehicle family, mounting a 105 mm tank gun, based on the Canadian LAV III light-armored vehicle manufactured by General Dynamics Land Systems for the U.S. Army.

The MGS program emerged after the 1996 cancelation of the Army's M8 Armored Gun System, the service's planned replacement for the M551 Sheridan light tank.

The MGS will be retired by the end of 2022.[5]


A Mobile Gun System and other Strykers shortly before being flown into Afghanistan in 2008


Replacing the Sheridan[edit]

Following the end of the Cold War some theorists believed that the existing suite of U.S. armored vehicles, designed largely to fight Soviet mechanized forces in Europe, were not well suited to the lower-intensity missions U.S. armed forces would be tasked with. This led to the development of a new armored fighting vehicle designed for lower-intensity combat, rather than large-scale battle.[citation needed]

By 1992, the Armored Gun System emerged as the top priority procurement program for the Army.[6] The Army requested proposals for a 20-ton air-droppable light tank to replace the M551 Sheridan. The Army sought 300 AGS systems to go to the 82nd Airborne Division and the 2nd Armored Cavalry Regiment. Four competitive bids emerged,[7] and in June 1992, the Army selected the FMC Close Combat Vehicle, Light proposal.[8] This was later type-classified as the M8 Armored Gun System. In 1996, the Pentagon canceled the AGS due to budget cuts across the services.

Interim Armored Vehicle[edit]

The Interim Armored Vehicle program included a requirement for a Mobile Gun System. A team of GM Defense of Canada and General Dynamics Land Systems proposed an MGS variant of the LAV III. United Defense LP proposed an M8 Armored Gun System (AGS) and two variants of the Mobile Tactical Vehicle Light (MTVL); one with the AGS turret and 105mm gun, and another with a 90mm gun.[9] Two other competing contractors submitted bids for infantry carriers, but declined to submit offers for the MGS requirement.[10]

Unlike the infantry carrier variants, MGS prototypes were not evaluated on the Army's proving grounds. This resulted in protests from lawmakers and industry officials. The service maintained that vehicle trials would be unnecessary and complicate the competition.[11]

GM-GDLS won the contract for both the infantry carrier and MGS, which was later type classified as the M1128.[12] GM-GDLS suspended work on the IAV while the Government Accounting Office evaluated UDLP's protest of the award. This protest was denied in April 2001.[13]

Soon after the contract was awarded, the MGS IOC date slipped two years from December 2001 to November 2003. The Army allowed GM-GDLS to substitute the Stryker ATGM variant for the MGS in the interim. In its protest, UDLP alleged that the Army had in fact known about the schedule slippage before awarding the contract, and unfairly disregarded this in their decision making.[14]

In 2000, the Army found its existing ammunition stockpile of 105mm rounds to be in poor condition, with more than half determined to be either unusable or obsolete. The Army solicited industry to produce new ammunition to replenish the stockpile.[9]

In March 2004, the Army approved the transfer of four AGS production vehicles to the 82nd Airborne Division to be used in Iraq. However, in June 2004, this plan was put on hold while the Army determined whether the MGS could meet the 82nd's requirements.[15] In August, the Army conducted an air-drop test of a Stryker M1132 Engineer Squad Vehicle weighted to simulate the load of the MGS. Around the same time, the Army identified issues with the air-dropability of the MGS, among the heavier of the Stryker family. Still more pervasive problems persisted with the autoloader.[16] In January 2005, the Army said it had ruled out fielding the AGS, saying the system lacked a spare parts inventory that would be required to maintain the vehicle for any significant length of time. The Army doubled down on its belief in the MGS, which it said it could begin fielding in summer 2006.[17]

After a Defense Acquisition Board review, the Pentagon, in October 2004, approved limited low-rate production of the MGS. During limited production, 14 vehicles would be produced. During this time, General Dynamics redesigned the ammunition handling system to be more reliable. In November 2004, the Pentagon approved an Army request to move the vehicle into low-rate production, to total 72 vehicle.[18]

After a Defense Acquisition Review, the Pentagon approved full-rate production of the MGS in February 2008.[19] However, the Army chose to defer production of new vehicles while it waited to validate fixes made to the MGS.[20]

Full-rate production was indefinitely deferred as of 2012.[21]

In late 2013, the U.S. Army began seeking to reintroduce an airdroppable mobile airborne protected firepower platform to provide fire support for air assault forces, a capability that had been absent since the retirement of the M551 Sheridan in 1997. General Dynamics initially considered modifying the wheeled Stryker MGS to meet the Mobile Protected Firepower (MPF) program requirement,[22][23] but the company instead entered a variant of the Griffin light tank.[24]


In May 2021, the Army announced they would divest all Mobile Gun Systems by the end of 2022. The decision was made following an analysis that found its autoloader had become expensive to maintain and that the M1128 had not been upgraded with a Double V-Hull, and that it was more efficient to eliminate the platform and focus on firepower improvements such as equipping Strykers with 30 mm cannons and CROWS-J mounts, providing better distributed lethality capabilities that will not be lost from removing the MGS.[5][25]

Foreign interest[edit]

Canada had liquidated about half of its fleet of Leopard 1 Main Battle Tanks in the early 2000s, with the intention of replacing them with the Mobile Gun System, but the decision was reversed.[26]



Mobile Gun System firing

The MGS's low profile turret has a small silhouette, is stabilized and mounts a 105mm M68A1E4 rifled cannon with a fume extractor and an autoloader. The vehicle is primarily outfitted to support infantry combat operations; while it could take on some of the roles of a tank, it is not primarily intended nor designed to engage in combat with main battle tanks. The MGS can store 18 rounds of main gun ammunition, 8 in the autoloader's carousel and an additional 10 in a replenisher located at the rear of the vehicle.[27] It has a rate of fire of ten rounds per minute.[28]

The reduced height required of the Stryker to meet the C-130 transportability requirement proved particularly challenging when applied to the MGS. The reduced distance between the muzzle brake and the hull caused blast overpressures to develop. A solution was found where the "pepper pot" could be covered by a sheet of metal.[29]

The MGS's 105 mm cannon can fire four types of ammunition: the M900 kinetic energy penetrator to destroy armored vehicles; the M456A2 high explosive anti-tank round to destroy thin-skinned vehicles and provide anti-personnel fragmentation; the M393A3 high explosive plastic round to destroy bunkers, machine gun and sniper positions, and create openings in walls for infantry to access; and M1040 canister shot for use against dismounted infantry in the open.[30][31]

Crew amenities[edit]

Because the vehicle was originally designed without air conditioning (A/C), crews were given cooling vests that circulate cooled water from outside the vehicle to the garment. Vehicle computers still overheated regularly. All MGS Stryker platforms have since been upgraded with A/C units.[32] The large weapon station and relatively smaller hatch can make emergency exits difficult.[1] Because the main cannon is separated from the crew compartment a gun stoppage during combat can only be cleared by disembarking from the vehicle.[citation needed]


The U.S. Army allocated nine Mobile Gun Systems to a battalion.[1] There were 27 Mobile Gun Systems per "Stryker brigade" in 2013, but later the Army cut the number per brigade to 10.[22] The Army bought 142 Mobile Gun Systems in total;[33] 3 were lost in combat. A three-vehicle MGS platoon operates organic to a Stryker infantry company, with one MGS in support of a Stryker infantry platoon.[34]

As of May 2017, a Stryker brigade combat team is equipped with three platoons of MGS Strykers and three platoons of ATGM Strykers in its weapons troop.[35]

See also[edit]


  1. ^ a b c Matthew Cox (4 February 2008). "Mobile Gun System brings the heat in Iraq". Gannett Government Media Corporation. Archived from the original on January 17, 2013. Retrieved 28 August 2011.
  2. ^ a b Green, Michael (22 Nov 2016). American Wheeled Armoured Fighting Vehicles. South Yorkshire, United Kingdom: Pen & Sword Books Ltd. p. 192. ISBN 978-1473854369. Retrieved 28 May 2020.
  3. ^ "Equipment: Mobile Gun System vs. Leopard tank". cbc.ca.
  4. ^ "Army Fact File – Stryker". Retrieved 2008-04-16.
  5. ^ a b The Army Is Ditching All of Its Stryker Mobile Gun Systems. Military.com. 12 May 2021.
  6. ^ Richard, Lardner (2 March 1992). "Service Emphasizes Lighter Forces: in New World, Armored Gun System Ranks as Army's Top Procurement Priority". Inside the Pentagon. Vol. 8, no. 11. Inside Washington Publishers. pp. 1, 11–13. JSTOR 43987842. Retrieved 23 January 2022.
  7. ^ "The Contenders: Four Teams Compete for Armored Gun System Contract". Inside the Pentagon. Vol. 8, no. 11. Inside Washington Publishers. 12 March 1992. p. 12. JSTOR 43987850. Retrieved 23 January 2022.
  8. ^ "Fmc Selected to Build Armored Gun System: Army's Ags to Feature All-welded Aluminum Hull, Detroit Diesel Engine". Inside the Pentagon. Vol. 8, no. 24. Inside Washington Publishers. 11 June 1992. p. 13. JSTOR 43988110. Retrieved 23 January 2022.
  9. ^ a b Burger, Kim (4 December 2000). "Stockpile May Not Be Suitable for New Lav III: Army Preparing to Procure 105 mm Ammunition for New Gun System". Inside the Army. Vol. 12, no. 48. Inside Washington Publishers. pp. 13–14. JSTOR 43985160. Retrieved 24 January 2022.
  10. ^ Burger, Kim (9 October 2000). "Iav Source Selection May Come This Week: Chosen Vehicle Less Important Than New Concept, Observers Say". Inside the Army. Vol. 12, no. 40. Inside Washington Publishers. pp. 7–9. JSTOR 43985072. Retrieved 23 January 2022.
  11. ^ Burger, Kim (29 May 2000). "Aberdeen Event Called a 'dipstick Check' Army Prepares for Iav Bid Sample Tests, Assures Controlled Setting". Inside the Army. Vol. 12, no. 21. Inside Washington Publishers. pp. 1, 12. JSTOR 43984790. Retrieved 24 January 2022.
  12. ^ "M8 Armored Gun System - Archived 3/2004". www.forecastinternational.com. Forecast International. Retrieved 28 March 2019.
  13. ^ Winograd, Erin Q. (7 May 2001). "GAO Releases Redacted Decision: UDLP Won't Pursue Further Action to Overturn Army's IAV Decision". Inside the Army. Vol. 13, no. 18. Inside Washington Publishers. JSTOR 43985396. Retrieved 23 January 2022.
  14. ^ Burger, Kim (15 January 2001). "In-lieu-of Vehicle Helped Gm-gdls Win, Company Says: Udlp Offers Additional Evidence of Army Bias in Favor of Lav III". Inside the Army. Inside Washington Publishers. pp. 1, 6–7. JSTOR 43984265. Retrieved 24 January 2022.
  15. ^ "GDLS given $500,000 to pursue air-drop test: Army to Delay Armored Gun System Delivery Until MGS Tests Complete". Inside Defense - Inside the Army. Vol. 16, no. 23. 7 June 2004. JSTOR 24822615. Retrieved 23 January 2022.
  16. ^ "Cody: Answer Could Lie Outside Army: Army Re-evaluates Airborne Division's Request for Ags-like Platform". Inside Defense - Inside the Army. Vol. 16, no. 44. 1 November 2004. JSTOR 24821748. Retrieved 23 January 2022.
  17. ^ "Rep. Hayes Dissatisfied With Response to Query on Ags: Army Still Backing Stryker Mgs to Fill Year-old Request for Firepower". Inside Defense -Inside the Army. Vol. 17, no. 6. 14 February 2005. JSTOR 24823120. Retrieved 23 January 2022.
  18. ^ DiMascio, Jen (14 November 2005). "Gd to Manufacture Three Mgss This Month: Krieg Allows Mobile Gun System to Move Into Low-rate Production". Inside the Army. Vol. 17, no. 45. Inside Washington Publishers. JSTOR 24823189. Retrieved 24 January 2022.
  19. ^ Censer, Marjorie (25 February 2008). "Now Awaiting Army Secretary Certification: DoD Approves Stryker Mobile Gun System for Full-rate Production". Inside the Army. Vol. 20, no. 8. Inside Washington Publishers. pp. 1, 9. JSTOR 24826412. Retrieved 24 January 2022.
  20. ^ Marjorie, Censer (24 August 2009). "Service to Wait for Validated Fixes: Army Defers Spending Fy-09 Funds on Stryker Mobile Gun System". Inside the Army. Vol. 21, no. 33. Inside Washington Publishers. pp. 1, 8–9. JSTOR 24830977. Retrieved 24 January 2022.
  21. ^ Brannen, Kate. "AUSA: U.S. Army Plans Post-War Management of Stryker Fleet." Defense News. February 23, 2012.
  22. ^ a b Matthew Cox (20 September 2013). "Army Looks to Mount 30mm Cannons on Strykers". Military.com. Retrieved 22 September 2013.
  23. ^ U.S. Army in the Market for ‘Light’ Tanks Archived 2016-01-19 at the Wayback Machine - Nationaldefensemagazine.org, 7 October 2013
  24. ^ General Dynamics presents new Griffin technology demonstrator of light tank for U.S. airborne troops - Armyrecognition.com, 5 October 2016
  25. ^ US Army scraps Stryker mobile gun systems in favor of new lethality upgrades. Defense News. 12 May 2021.
  26. ^ Major Howard Mark Anthony, Close Combat Vehicle and Leopard 2 Main Battle Tank: Back in the Heavyweight Fight, Canadian Forces College, pg 13, Footnote 21, https://www.cfc.forces.gc.ca/259/290/298/286/anthony.pdf Accessed 2019-11-17
  27. ^ "Stryker mobile gun system replenisher". Meggitt Defense. Retrieved 30 July 2018.
  28. ^ Ogg, David (2001-06-18). "The Road To The Objective Force "Armaments for the Army Transformation"" (PDF). Firepower Symposium: 32. Archived (PDF) from the original on November 5, 2020.
  29. ^ Plummer, Anne (21 July 2003). "Lowered Turret Complicates Design: After Brief Hiatus, Army Resumes Stryker Mobile Gun System Testing". Inside the Army. Vol. 15, no. 29. JSTOR 24820277. Retrieved 24 January 2022.
  30. ^ M1128 Stryker Mobile Gun System - Globalsecurity.org
  31. ^ "Archived copy" (PDF). Archived from the original (PDF) on 2014-08-26. Retrieved 2014-08-22.{{cite web}}: CS1 maint: archived copy as title (link)
  32. ^ "PM (Preventive Maintenance) Keeps Strykers Combat Ready!" (PDF). Logistics Support Activity. Retrieved 30 July 2018.
  33. ^ Uparmored Bradley Could Be Tough Enough For AMPV: Testers - Breakingdefense.com, 29 January 2014
  34. ^ Stryker Mobile Gun System (MGS) Archived 2014-10-19 at the Wayback Machine – Office of the Director, Operational Test & Evaluation. 2013
  35. ^ "Stryker Brigade Combat Team Weapons Troop" (PDF). Army Publishing Directorate. Retrieved 30 July 2018.

External links[edit]

Media related to Stryker Mobile Gun System at Wikimedia Commons