Names：

Guncannon Heavy Arms Type

（RX-77-3）
Status： MS of E.F.F
Tags： Mobile SuitEarth Federation Forces (U.C.)Prototype
Development： Guncannon IIGuncannon
World： the World of Mobile Soldiers
Works： Mobile Suit Z GundamUniversal Century Series
LeveL： A

Following the development of the RGC-80 GM Cannon, a mass production variant of the RX-77-2 Guncannon, the Federation continued its development of medium-range support mobile suits. Based on the combat data of the RX-77-2, the Federation developed the RX-77-3 Guncannon Heavy Custom.

Compared to its predecessor, the RX-77-3 omitted the Core Block System and featured improved armor, reduced recoil, increased payload, rate of fire, and reloading speed. Its backpack output was also increased in an attempt to improve its mobility. However, it was said that its weight was more than its basic design could support, hindering its mobility. In addition, while it was intended to be able to operate in both group and solo combat, its solo operation capability was said to be lacking.

Despite the RX-77-3's improvements, the recoil of its ballistic cannons were still an issue. In order to solve the problem completely, some test units had their cannons replaced with a single beam cannon for trial purposes.

Following the development of the RGC-80 GM Cannon, a mass production variant of the RX-77-2 Guncannon, the Federation continued its development of medium-range support mobile suits. Based on the combat data of the RX-77-2, the Federation developed the RX-77-3 Guncannon Heavy Custom.

Compared to its predecessor, the RX-77-3 omitted the Core Block System and featured improved armor, reduced recoil, increased payload, rate of fire, and reloading speed. Its backpack output was also increased in an attempt to improve its mobility. However, it was said that its weight was more than its basic design could support, hindering its mobility. In addition, while it was intended to be able to operate in both group and solo combat, its solo operation capability was said to be lacking.

Despite the RX-77-3's improvements, the recoil of its ballistic cannons were still an issue. In order to solve the problem completely, some test units had their cannons replaced with a single beam cannon for trial purposes.