The RX-77D Guncannon Mass Production Type was a mass production evaluation variant of the RX-77-2 Guncannon deployed near the end of the One Year War. Based on the RX-77-3 Guncannon Heavy Custom, the Guncannon Mass Production Type similarly omitted the Core Block System. To improve productivity, it shared many parts with the late production type RGM-79G GM Command and its armor was made of titanium ceramic composite. To reduce blind spots and inertial momentum during movement and close-quarters combat, its back-mounted low-recoil cannons were made semi-retractable. Additionally, the ammunition feeding mechanism of the low-recoil cannons was simplified compared to the original Guncannon and relocated. Because of these changes, its backpack was enlarged, but there were also improvements in productivity and ease of maintenance. For precision firing, a stabilizer gear in the bottom-rear pelvic section could extend to the ground, improving the mobile suit's stability.
Guncannon Mass Production Type
（RX-77D）The RX-77D Guncannon Mass Production Type was a mass production evaluation variant of the RX-77-2 Guncannon deployed near the end of the One Year War. Based on the RX-77-3 Guncannon Heavy Custom, the Guncannon Mass Production Type similarly omitted the Core Block System. To improve productivity, it shared many parts with the late production type RGM-79G GM Command and its armor was made of titanium ceramic composite. To reduce blind spots and inertial momentum during movement and close-quarters combat, its back-mounted low-recoil cannons were made semi-retractable. Additionally, the ammunition feeding mechanism of the low-recoil cannons was simplified compared to the original Guncannon and relocated. Because of these changes, its backpack was enlarged, but there were also improvements in productivity and ease of maintenance. For precision firing, a stabilizer gear in the bottom-rear pelvic section could extend to the ground, improving the mobile suit's stability.