The first Prototype GM Cannon created under this plan was rolled out in Jaburo in October of U.C. The Earth Federation Forces' plan was to retain the Core Block function of the Core Fighter, with the mobile suit's upper body equipped with cannons for medium-range support.
However, in line with the core of the RX Project, which is to create a multipurpose, easily convertible mobile suit, the design of the Guncannon needed to be simplified. The RX-77 Guncannon's overall performance as a medium-range support machine was excellent and plans were made to put it into mass production.
