A middle-range support mobile suit developed simultaneously with the RX-78 Gundam and the RX-75 Guntank as part of Operation V, the Guncannon adopted the same Core Block System as the other two units. Due to its role as an artillery support unit, the Guncannon's design prioritized durability over mobility, and it was not equipped with any melee weapons. However, its armor was particularly heavy, capable of surviving a direct hit from a MS-09R Rick Dom's giant bazooka.
Similar to the Guntank, the Guncannon's main weapons were a pair of shell-firing cannons, chosen for their reliability over beam weapons. These cannons could be optionally swapped out for a pair of spray missile launchers. Unlike the Guntank, however, the Guncannon's generator output allowed it to equip a beam rifle. It was also equipped with a pair of head-mounted vulcan guns and hand grenades for attacking enemy strongholds. The fire control of the Guncannon was primarily handled by the sensor array and coprocessor system in the head.