The most heavily armed variant of the Styker family is the M1128 Mobile Gun System. It boasts a 105mm M68A2 rifled main gun in a turret that is supported by an autoloader. It is designed more for infantry support missions rather than tank engagements, and carries four different types of ammunition rounds. The MGS weighs approximately 18.5 tons and operates with a crew of three. The US Army obtained 142 units of the MGS.
