Technology & Combat Characteristics
The successor of the RGC-80 GM Cannon, a medium-range support mobile suit developed in the late stage of the One Year War, the RGC-83 GM Cannon II was based on the RX-77D Guncannon Mass Production Type and inherited the Chobam Armor concept of the RX-78NT-1 Gundam NT-1. It was the culmination of the Federation's artillery support mobile suit development.
Thanks to improvement in technology and productivity, the GM Cannon II was installed with a powerful generator, allowing it to be equipped with two shoulder-mounted beam cannons. This made it the first mass production unit to have integrated high-powered beam cannons. These beam cannons were usually powered by the generator itself, but could also be powered by the two Energy CAP mounted on its backpack. A sighting device located on the pilot seat's headrest could be used to aim the beam cannons. The GM Cannon II also had relatively poor mobility due to the mass of its weapons and armor.
The design of the GM Cannon II's basic components prioritized parts interchangeability with GM type mobile suits. Parts of its exterior was covered in composite armor, similar to the Chobam Armor used by the RX-78NT-1 "Alex". This composite armor improved bullet resistance while keeping the mobile suit's weight down. Unlike the Alex's Chobam Armor, the composite armor was built directly onto the frame and could not be purged when damaged. Despite their structural differences to Alex's armor, the composite armor was often also referred to as "Chobam Armor" for convenience.
Like the GM Custom, there was a plan to mass produce the GM Cannon II, but due to issues such as cost and the fact that the machine was meant to operate alongside the GM Custom, only a few units were actually deployed. After the Delaz Conflict, the project itself, including its development staff, was placed under the control of the Titans. The GM Cannon II's production was halted and a direct successor to it was never developed.
History
The RGC-83 GM Cannon II was manufactured by the Federation's Jaburo factory.
One of the GM Cannon IIs was piloted by Immortal 4th Team member Chap Adel and the other was piloted by Chuck Keith, a rookie pilot from Torrington Base. Both suits saw action on October 23, when the Albions mobile suit team engaged the Kimberlite Forces, a group of Zeon Remnants based in East Africa. The Kimberlite Forces was eventually defeated, but the GP02A escaped into space using an HLV in the group's base.
When the Albion pursued the GP02A into space, Keith, piloting his GM Cannon II, took part in a mock battle against the Immortal 4th Team to familiarize himself with space combat. When the Albion came under attack by Cima Garahau's fleet, both GM Cannon IIs deployed in response. Though they failed to achieve any significant battle results against the more nimble MS-14F Gelgoog Marines, they were able to stop them from breaking through. However, the situation changed when Cima joined the battle herself in her MS-14Fs Gelgoog Marine Commander Type. Leading two Gelgoog Marines, she easily took the inexperienced Keith out of the fight and broke through to the Albion. Ultimately, however, she was forced to retreat when both of her wingmen were destroyed.
After the Albion departed from Von Braun, former Zeon mobile armor pilot Kelley Layzner deployed in the MA-06 Val Walo and intended to destroy the RX-78GP01Fb Gundam GP01Fb "Zephyranthes Full Burnern" to prove himself. When Kou Uraki deployed in the GP01Fb to stop Kelley, the latter trapped the Gundam using the Val Walo's Plasma Leaders. At this point, Keith deployed in the GM Cannon II and fired its beam cannons at the Val Walo, but ended up missing. He then fired his rifle at one of the Plasma Leaders, destroying it and freeing the GP01Fb which eventually destroyed the Val Walo.
On November 8, the Albion encountered the Cima Fleet again while Cima was trying to trade the plans for Operation Stardust to the Federation flagship Birmingham. Unaware of their secret deal, the Albion deployed its mobile suits against the Cima Fleet. Kou, Burning, and Keith deployed in their respective mobile suits and engaged the Cima Fleet's Geloog Marines, forcing them to retreat.
Two days later, on the day of the Federation naval review at Confeito, both of Albions GM Cannon IIs, along with the rest of the Albion mobile suit team, deployed repeatedly to stop waves after waves of Zeon Remnants from reaching the naval review. However, they ultimately failed to stop Anavel Gato from reaching the naval review and firing the GP02A's nuclear payload at the gathered Federation fleets. Later, Keith's GM Cannon II recovered Kou after the latter's GP01Fb was destroyed in a duel with the GP02A.
During the battle to stop the Delaz Fleet's colony drops, all of the Albions mobile suits, including both GM Cannon IIs, fought near continuously through waves of Zeon mobile suits, eventually standing on Albion itself and acting as turrets. When Keith saw Nina Purpleton heading for the falling colony in the FF-XII-Fb Core Fighter II Full Burnern, he tried to follow her in his GM Cannon II, but ended up pinned by Zeon fire.
A GM Cannon II piloted by Ben Wooder was deployed to the Federation Fleet led by Green Wyatt to attack the Principality of Zeon base "Varsika", which was hiding in the Zebra Zone in March, U.C. 0083.
In U.C. 0084, a GM Cannon II piloted by Titans' mobile suit pilot, Agar, was used to support the RGM-79Q GM Quels hunting Zeon remnants during a riot in the lunar city of Ayers
In U.C. 0087, a GM Cannon II was operated by AEUG along with the GM Custom, and they were deployed from the Argama.