Technology and Combat Characteristics
A mid-range support suit developed by the Earth Federation Forces. From its appearance and name, many might think that it is a cannon-type configuration of the RGM-79 GM (Thunderbolt Ver.), but it is actually a simplified mass production version of the RX-77 Guncannon (Thunderbolt Ver.). Like the GM (Thunderbolt Ver.), the GM Cannon (Thunderbolt Ver.) has added sensors on its head for better search capabilities in the debris-filled area and its joints are covered in special seals to protect them from the debris. The GM Cannon (Thunderbolt Ver.) has a large backpack with a cannon mounted on the right and a sub arm on the left. It also has added thrusters on its calves.
In the manga, the Beehive was supplied with the FA-78 Full Armor Gundam (Thunderbolt Ver.), RX-77 Guncannon (Thunderbolt Ver.)s, RB-79 Ball (Thunderbolt Ver.)s, GM Cannon (Thunderbolt Ver.)s, student volunteer pilots and ammunitions for the final battle in Side 4. Used by the student volunteers and pilots of the Beehive, the GM Cannons and other mobile suits were used in a diversion tactic (rather controversially) to outnumber the Living Dead Division's snipers and overwhelm them so the FA-78 Full Armor Gundam (Thunderbolt Ver.) could sink the main fleet.
Although the novice pilots were no match for the snipers, they managed to take out a few snipers through sheer numbers. They were engaged by Fisher Ness in his MS-09R Rick Dom (Thunderbolt Ver.) who took out at least one Ball and 3 GM Cannons. Although unknown to the pilot of a Guncannon (the last surviving member of the squadron), the MS-06R Zaku II High Mobility Type (Reuse "P" Device) had mopped up all of the MS deployed, and the GM Cannons were completely decimated.
Later, a few GM Cannons were seen battling Zeon's main fleet and subsequently guarding the Dried Fish after it was captured by the Federation Forces. One GM Cannon pllayed a major role in stopping the captured from blowing up the ship. When the Federation surrendered to Zeon, the GM Cannons were used to transport Federation and Zeon soldiers to a Chivvay-class. It is unknown what happened to the GM Cannons after this event.