Compared to the beam rifle used by the RX-78-2 Gundam, it was harder to use but had higher accuracy and longer range. This particular beam rifle is specialized for sniping. The Guncannon Heavy Type D can use the same beam rifle as the RX-77-2 Guncannon. Like the ones used by the Guncannon Heavy Custom, the Guncannon Heavy Type D's cannons have a higher rate of fire, better ammunition feed system and cause less recoil when fired than those of the RX-77-2 Guncannon. Low offensive power, only used to restrict enemy movement, and lay down a wall of suppressive fire due to their rapid fire capability.Ī pair of shoulder-mounted 240mm cannons served as the Guncannon Heavy Type D's main weapon. Ī pair of shell-firing armament built into the head. However, due to its high cost and the completion of the superior RX-77-4 Guncannon II soon after, the Guncannon Heavy Type D was produced only in limited numbers. After the first Guncannon Heavy Type D unit displayed high performance during tests, the suit was formally adopted by the Earth Federation Forces. Armament wise, it has similar weapons as the original Guncannon and Guncannon Heavy Custom. Thus, although a mid-range support unit, it can also function as a general-purpose unit with performance close to that of a melee combat machine. With its enhanced mobility, the Guncannon Heavy Type D's combat range also widens. Interestingly, the Guncannon Heavy Type D reverts to the knee armor of the original Guncannon. Thanks to the four new leg thrusters, the increase in weight caused by this added armor does not affect the suit's mobility. It also has additional armor on its head and shoulders. The Guncannon Heavy Type D has additional vernier thrusters on its backpack and legs to improve mobility.
To address this issue, one of the Guncannon Heavy Customs was improved into the RX-77-3D Guncannon Heavy Type D upon orders from the Earth Federation Forces. Although the RX-77-3 Guncannon Heavy Custom is an improvement over the RX-77-2 Guncannon, with lower recoil when firing the cannons and better weapons as well as armor capabilities, though its mobility still left much to be desired.