Based off the combat data of the RX-78-2 Gundam, the RX-78-6 Mudrock Gundam was designed to address the biggest shortcoming in the former's design - a lack of weaponry once the Gundam's primary beam rifle was out of energy. To get around this limitation, the Mudrock was built as a sustained-combat unit with higher firepower.
It has a prototype CAP beam rifle backed up by a pair of arm-mounted grenade launchers, and a pair of 300mm low-recoil cannons inspired by the RX-77-2 Guncannon. To further increase the Mudrock's survivability, it has improved frontal armor, and also retained the Gundam's beam sabers and head vulcans. The added payload increased the suit's weight by roughly one-third. To prevent this from affecting the suit's mobility, the Mudrock was equipped with a reactor with higher output, an enlarged backpack, and the legs are fitted with movable side thrusters that allow hovering for limited amounts of time.