Earth Federation Mobile Suit
RGC-80-1 GM Cannon Test Type

To supplement the modest firepower of the RGM-79 GM, the Earth Federation decided to produce a mid-range support mobile suit based on the prototype RX-77 Guncannon. However, wartime conditions made it impractical to set up production lines for an entirely different type of mobile suit. Thus, instead of mass-producing the Guncannon, the Federation set out to create a substitute based on the GM.

The first test unit of the GM Cannon, completed in October of UC 0079, was essentially a standard GM with the Guncannon's head and cannons. However, this lightweight, topheavy mobile suit suffered from severe balance problems while firing its cannons. Clearly, a redesign was in order.

Though text descriptions of the RGC-80-1 exist, the only visual depiction of it is the "Super Deformed" version.

Illustration by Mark Simmons

Specifications

Model number / RGC-80-1

Standard armament /
  60mm vulcan gun x 2
  240mm cannon x 2

Earth Federation Mobile Suit
RGC-80 GM Cannon

The final version of the GM Cannon featured a number of modifications to address the test type's balance problems. Heavier leg armor lowered its center of gravity, and the two shell-firing cannons were replaced by a single 240mm rocket launcher to minimize recoil. Since the GM Cannon used 60% of the same parts as the GM, it could be built on the same production lines, and could use standard GM equipment like a beam spray gun, bazooka, and shield.

The GM Cannon first appeared on the battlefield in North America. Six units were used in the Federation's counteroffensive, each assigned to support a team of standard GMs. After the recapture of the California Base on December 15, these GM Cannons were repainted in winter camouflage. Another 19 units were sent to the African front, 14 assigned to Admiral Tianem's space fleet for Operation Star One, and 9 retained at Jaburo for base defense - a total of 48 units in all. The GM Cannon was also used in Australia, where one or two were assigned to Master P. Rayer's White Dingo team.

Illustration by Mark Simmons

Specifications

Model number / RGC-80
Overall height / 18.4 m
Head height / 18.0 m
Base weight / 49.9 t
Full weight / 65.3 t
Generator output / 976 kW
Thruster /
  63500 kg
Sensor radius / 6000 m
Land speed / 83 km/h

Standard armament /
  60mm vulcan gun x 2
  240mm cannon x 1
  beam rifle x 1

Source: Gundam Mechanics I