The RMS-179 GM II Semi-Striker is a custom RMS-179 GM II created at the Torrington Base by reusing spare parts from existing machines, thus its model number is unchanged from the original GM II. Its name "Semi Striker" came about due to its appearance. It shares the same performance, power output, acceleration, and sensor range as the GM II, but its OS was rewritten to specialize in close-combat. The shoulder armor are refitted with armor plates that resembles RGM-79FP GM Striker's, but they do not have the same ability. Its left forearm is equipped with a small shield similar to the FA-78-1 Full Armor Gundam's. The GM II Semi-Striker is usually equipped with a pair of 60mm vulcan guns, a beam saber, and the GM Striker's twin beam spear.
In UC 0096, during the assault of Torrington Base by Zeon Remnants, a GM II Semi-Striker was defeated by the MS-08TX/S Efreet Schneid in close quarters combat.