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 originCanada, United States
Service history
WarsIraq War[1]
War in Afghanistan
Production history
DesignerGM Defense of Canada, 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]
M68A2 105 mm cannon[5]
7.62 mm 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 US gallons (212 liters)
330 miles (528 km)
Maximum speed 60 mph (96 km/h)

The M1128 Mobile Gun System (MGS) 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 was procured in limited numbers. It will be retired by the end of 2022 due to design and operational deficiencies.[6][needs update]


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

Background: 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.[citation needed]

This led to the development of a new armored fighting vehicle designed for lower-intensity combat, rather than large-scale battle.[7]

By 1992, the Armored Gun System emerged as a top priority procurement program for the Army.[8] 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.[9]

In June 1992, the Army selected the FMC Close Combat Vehicle, Light proposal.[10] This was later type-classified as the M8 Armored Gun System. In 1996, the Army canceled the AGS due to the service's budgetary constraints.[11]

Interim Armored Vehicle competition[edit]

The General Dynamics Mobile Gun System originated from the Canadian Armoured Combat Vehicle requirement.[12] In partnership with General Motors, General Dynamics Land Systems (GDLS)–Canada integrated its Low Profile Turret (LPT) onto a LAV III in January 1999.[13] The turret was an updated version of the one used on the GD–Teledyne Expeditionary Tank, which was entered into the Armored Gun System competition in the 1980s.[14]

In October 1999, U.S. Army Chief of Staff Eric Shinseki laid out his vision for a lighter, more transportable force. He called for mid-weight brigades that would strike a balance between heavy armor and infantry.[15] The Army subsequently launched the Interim Armored Vehicle acquisition program. One of the required vehicles was the Mobile Gun System (MGS).

A team of GM Defense of Canada and GDLS submitted a variant of the LPT Assault Gun to meet the MGS requirement. General Dynamics was responsible for most of the MGS.[12][clarification needed] 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.[16] Two other competing contractors submitted bids for infantry carriers, but declined to submit offers for the MGS requirement.[17]

Unlike the infantry carrier variant, MGS prototypes were not evaluated on the Army's proving grounds. This resulted in protests from lawmakers and industry officials. The service maintained that bid samples would be unnecessary and complicate the competition.[18]

In September 2000, the Army told bidders it was considering plans to increase by 200 the number of MGS units purchased. Though the service did not say why it was interested in more MGS units, however Defense Daily speculated that the Army could equip light divisions with the MGS.[19]

In November 2000, GM–GDLS won the contract for both the infantry carrier and MGS. The MGS was later type classified as the M1128.[20][21] GM–GDLS was forced to suspend work on the IAV while the Government Accounting Office evaluated UDLP's protest of the award. GAO denied the protest in April 2001.[22]

Further development and initial production[edit]

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 known about the schedule slippage before awarding the contract, and unfairly disregarded this in their decision making.[23]

GDLS delivered the first of eight pre-production Mobile Gun Systems in July 2002.[5]

In March 2004, the Army approved the transfer of four AGS production vehicles to the 82nd Airborne Division to be used in Iraq. In June 2004, this plan was put on hold while the Army determined whether the MGS could meet the 82nd's requirements.[24] 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.[25]

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.[26]

In October 2004, the Pentagon approved limited low-rate production of the MGS after a Defense Acquisition Board review. During limited production, 14 vehicles were 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 a total of 72 vehicles.[27]

On February 2008, the Pentagon approved full-rate production of the MGS after a Defense Acquisition Review.[28] The Army chose to defer production of new vehicles while it waited to validate fixes made to the MGS.[29]

In 2010, GDLS began incorporating explosive reactive armor on MGS production units.[5]

Full-rate production was indefinitely deferred in 2012.[30]

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,[31][32] but the company instead entered a variant of the Griffin light tank.[33]

As of May 2016, 3 Mobile Gun Systems had been written off during combat operations out of 142 produced.[5]


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. 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.[6][34]

Foreign interest[edit]

Canada had liquidated about half of its fleet of Leopard 1 main battle tanks in the early 2000s.[35] The Canadian Army planned to replace the MBTs with 66 Mobile Gun Systems. However in 2007, the Canadian Army reversed itself and decided instead to procure Leopard 2s.[5]

Combat use[edit]

The Mobile Gun System saw service in the Iraq War and the War in Afghanistan.[5]


Armor and protection[edit]

The MGS has integral all-around armor protection against 14.5 mm AP rounds.[36]

The MGS commander and gunner are located in the turret basket, which provides the crew some separation from the ammunition in the event of an explosion. According to a Government Accounting Office report released in May 2001, the Army had expressed doubt that this arrangement would provide "any protection from secondary explosions and fires from the main gun ammunition."[36]


A 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 or designed to engage in combat with main battle tanks.[37]

The MGS can store 18 rounds of main gun ammunition: 8 in the autoloader's carousel and 10 in a replenisher located at the rear of the vehicle.[38] It has a rate of fire of ten rounds per minute.[39]

The MGS was originally developed for the Canadian Army, which did not have a requirement for transporting the vehicle via C-130. The U.S. Army did have this requirement, and so a design change was required to lower the MGS's height so that the vehicle could fit inside the aircraft. The turret was lowered within the hull.[40] This change caused problems of its own. 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.[41]

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 squash head 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.[42][43]

In 2001, Rheinmetall announced that it was seeking to incorporate its 105 mm smoothbore low recoil gun on the MGS around 2004. The Army had not articulated such a requirement.[44]

By 2000, the Army found its existing ammunition stockpile of 105 mm 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.[16] L3 Communications completed low rate production of M393 high-explosive plastic HEP-T and M467 training rounds in 2004. 10,000 combat and 18,400 training rounds were ultimately produced by L3.[5]

Secondary armament[edit]

The coaxial weapon is an 7.62 mm caliber M240 machine gun. The commander's weapon is a 7.62 mm caliber machine gun in a skate mount. Alternately an M2 Browning .50 caliber machine gun or a 40 mm Mk 19 grenade launcher can be mounted.[5]

Differential attributes and failures[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.[45] The large weapon station and relatively smaller hatch can make emergency exits difficult.[1]

The main cannon is separate from the crew compartment. A gun stoppage during combat can be cleared only by exiting the vehicle.[citation needed]

M1128 suffered of lack of reliability, excessive dead space, gun size and gun control issues, taking its development to a limited production in 2010 with 142 units in service.[46]


As originally projected the U.S. Army allocated nine Mobile Gun Systems (3 per infantry company) to a battalion,[1] making for 27 Mobile Gun Systems per "Stryker brigade" in 2013, but later the Army cut the number per brigade to 10.[31]

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.[47]

The Army purchased 142 Mobile Gun Systems in total.[48] Three were lost in combat. The Army planned to authorize 32 Mobile Gun Systems to a Stryker Brigade Combat Team (BCT). However due to the low numbers produced, only nine were allocated to a BCT.[5]

A three-vehicle MGS platoon operates organic to a Stryker infantry company, with one MGS in support of a Stryker infantry platoon.[49]

See also[edit]


  1. ^ a b c Cox, Matthew (4 February 2008). "Mobile Gun System brings the heat in Iraq". ArmyTimes. Gannett Government Media Corporation. Archived from the original on January 17, 2013. Retrieved 28 August 2011.
  2. ^ a b Green, Michael (22 November 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 c d e f g h i Foss, Christopher F. (2017). Jane's Land Warfare Platforms: Armoured Fighting Vehicles 2017-2018. Surrey: Janes Information Group. pp. 269–271. ISBN 978-0-71063-227-2.
  6. ^ a b The Army Is Ditching All of Its Stryker Mobile Gun Systems. Military.com. 12 May 2021.
  7. ^ Rottman, Gordon L. (2012-09-20). Stryker Combat Vehicles. Bloomsbury Publishing. ISBN 978-1-78200-490-5.
  8. ^ 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.
  9. ^ "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.
  10. ^ "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.
  11. ^ Sherman, Jason (12 February 1996). "Service Still Seeking OSD Support: Army's Decision to Terminate AGS Meets Stiff Resistance on Capitol Hill". Inside the Army. Vol. 8, no. 6. Inside Washington Publishers. pp. 1, 9–10. JSTOR 43982648.
  12. ^ a b Baumgardner, Neil (1 September 2000). "General Motors Trumpets General Dynamics Deal For Meeting IAV Requirements". Defense Daily. Vol. 207, no. 44. Access Intelligence. Retrieved 18 January 2023.
  13. ^ Foss, Christopher F., ed. (2011). "Reconnaissance Vehicles". Jane's Armour and Artillery 2011–2012 (32nd ed.). Surrey: Janes Information Group. pp. 219–221. ISBN 978-0-71062-960-9.
  14. ^ Baumgardner, Neil (22 November 2022). "Competitors Line Up for Medium Armored Vehicle". Defense Daily. Vol. 204, no. 35. Access Intelligence. Retrieved 18 January 2023.
  15. ^ MacRae, Catherine (14 October 1999). "Service Wants to Be Lighter, Faster, More Lethal: Army Chief of Staff's 'vision' Is Focused on Medium-weight Force". Inside the Army. Vol. 15, no. 41. Inside Washington Publishers. p. 6. JSTOR 43995956. Retrieved 7 February 2022.
  16. ^ 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.
  17. ^ 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.
  18. ^ 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.
  19. ^ Baumgardner, Neil (29 September 2000). "Army Interested In Possible Buy Of 200 Additional Mobile Gun Systems". Defense Daily. Vol. 207, no. 63. Access Intelligence. Retrieved 18 January 2023.
  20. ^ Burger, Kim (20 November 2000). "LAV Variants Will Require Some Development: Testing of New Interim Vehicle May Upset Army's Fielding Schedule". Inside the Army. Vol. 12, no. 46. Inside Washington Publishers. pp. 1, 6–7. JSTOR 43985129. Retrieved 6 February 2022.
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  22. ^ 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.
  23. ^ 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.
  24. ^ "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.
  25. ^ "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.
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  27. ^ 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.
  28. ^ 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.
  29. ^ 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.
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  32. ^ U.S. Army in the Market for ‘Light’ Tanks Archived 2016-01-19 at the Wayback Machine - Nationaldefensemagazine.org, 7 October 2013
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  34. ^ US Army scraps Stryker mobile gun systems in favor of new lethality upgrades. Defense News. 12 May 2021.
  35. ^ 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
  36. ^ a b "United Defense Decides Against Taking IAV Protest To Court". Defense Daily. Vol. 210, no. 23. Access Intelligence. 2 May 2001. Retrieved 18 January 2023.
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  38. ^ "Stryker mobile gun system replenisher". Meggitt Defense. Retrieved 30 July 2018.
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  40. ^ Baumgardner, Neil (14 April 2000). "United Defense Disappointed by Cancellation of IAV Mobile Gun System Vehicle Evaluation". Defense Daily. Vol. 206, no. 10. Access Intelligence. Retrieved 18 January 2023.
  41. ^ 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.
  42. ^ M1128 Stryker Mobile Gun System - Globalsecurity.org
  43. ^ "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)
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  45. ^ "PM (Preventive Maintenance) Keeps Strykers Combat Ready!" (PDF). Logistics Support Activity. Retrieved 30 July 2018.
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  47. ^ "Stryker Brigade Combat Team Weapons Troop" (PDF). Army Publishing Directorate. Retrieved 30 July 2018.
  48. ^ Uparmored Bradley Could Be Tough Enough For AMPV: Testers - Breakingdefense.com, 29 January 2014
  49. ^ Stryker Mobile Gun System (MGS) Archived 2014-10-19 at the Wayback Machine – Office of the Director, Operational Test & Evaluation. 2013

External links[edit]

Media related to Stryker Mobile Gun System at Wikimedia Commons