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 Mobile Gun System (MGS) for lower-intensity combat, rather than large-scale battle.
The M1128 Mobile Gun System low profile turret has a small silhouette, is stabilized and mounts a 105mm M68A2 rifled cannon with an autoloader. The vehicle is primarily outfitted to support infantry combat operations. While it could take on some of the roles of tanks, it is not designed to engage in combat with 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. It has a rate of fire of six rounds per minute.
The Stryker MGS’ 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.
The U.S. Army allocated nine Mobile Gun Systems to a battalion. There were 27 Mobile Gun Systems per Stryker Brigade in 2013, but the Army is cutting the number per brigade to 10. The Army bought 142 Mobile Gun Systems in total; three 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. 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.