Following the success of the high-performance GM Sniper Custom, the Earth Federal Forces commissioned an improved version for use in the planned invasion of Zeon's home territory. Due to the tight one-month deadline for designing and first rollout, the GM Sniper II was based on the development RGM-79G GM Commando, and was the most powerful GM variant built during the war. Featuring special targeting sensors in its sliding visor for its standard sensors, the GM Sniper II could be equipped with a beam rifle or 90 mm machinegun for close-quarters combat, or a long-range, projectile-firing rifle for sniper missions.hough it lacked the standard 60mm vulcan guns, an optional vulcan pod could be attached to the side of its head.

Despite the developers' efforts, the GM Sniper II didn't appear in the battlefield until the final days of the war. Two prototype units, assigned to the "Scarlet" team aboard the assault carrier Gray Phantom, were destroyed in a skirmish at Side 6's Libot colony on December 19, UC 0079. Additional units were assigned to Australian forces like the White Dingo team, and were used in the assault on the Hughenden HLV base on January 2, UC 0080.

Source: Gundamproject.com, Gundam 0080: War in The Pocket