The RGC-80 GM Cannon is a mass-produced artillery mobile suit and a variant of the RGM-79 GM. It is featured in the original design series Mobile Suit Variations and in the anime series Mobile Suit Zeta Gundam.
Technology & Combat Characteristics
Originally, it was planned for the RX-77-2 Guncannon to be mass-produced with a few tweaks to its design, but in consideration of the wartime situation, the design was changed to make use of the existing production line of the RGM-79 GM. Following a series of trial and error, the GM Cannon was created as a simplified mass production model of the Guncannon. A medium-range support mobile suit, the GM Cannon shares 60% of its parts with the GM, and has a high initial velocity cannon of the same caliber as the Guncannon's attached to its notched right shoulder. Its legs are fitted with removable left and right split type increased armor to maintain the mobile suit's balance when firing the cannon during ground combat.
- 240mm Cannon
- Mounted over the right shoulder, this artillery cannon is for mid-range fire support. Two spare magazines can be mounted on the rear waist armor.
- 60mm Vulcan Gun
- A pair of shell-firing armament built into the head. Low offensive power, only used to restrict enemy movement, and lay down a wall of suppressive fire due to their rapid fire capability.
- BR-M-79C-1 Beam Spray Gun
- A handheld mega-particle gun with a lower focusing rate than a beam rifle and short-range. The beam spray gun features three different firing modes: a basic single-shot mode, a burst shot mode for area suppression, and a range shot mode that scatters the beam to cause damage over a wide area. Output 1.4 MW.
- YHI YF-MG100 100mm Machine Gun
- The standard armament for Federation's mobile suit ground forces during the One Year War that was developed by Yashima Heavy Industries. It has an alternate model number: "NF·GMG-Type.37/100mm". Equipped with a box magazine and folding stock, it has excellent rate of fire and is easy to wield. It utilized a smoothbore type barrel that lacked rifling and has to be replaced after firing 3000 rounds. The weapon could utilize three different types of ammunitions: HEAT (High Explosive Anti Tank), APFSDS (Armor-Piercing Fin-Stabilized Discarding-Sabot), and HESH (High Explosive Squash Head), allowing combat units to select the appropriate type to meet operational needs.
- HWF GMG·MG79-90mm Bullpup Machine Gun
- The bullpup machine gun was a system weapon developed as a Space/Ground dual use projectile weapon. Though compact, it has sufficient anti-MS firepower while maintaining accuracy. Its muzzle velocity is increased due to the use of new gunpowder and this enables it to easily penetrate the armor of Zeon's mobile suit. A box-like sensor system incorporating a video camera and laser sensor is installed at the top, and when this system is used alongside the GM's targeting system, target acquisition capability is enhanced.
- BOWA BG-M-79F-3A Beam Gun
- A next-generation beam weapon developed as a testbed for a new category of weapon between the Beam Rifle and the Beam Spray Gun, resulting in the new ‘Beam Gun’ category. The most unique features of the BG-M-79F-3A was the large beam accelerator and battery pack located on top of the rear portion of the weapon. These mechanics created a type of beam, that in addition to pinpoint penetration of targets, also has the side effect of cutting through the internal systems of the target, which proved to be very effective at disabling the said target.
- BOWA·BR-S-85-C2 Beam Rifle
- The same weapon as used by RMS-179 GM II, it has a power rating of 1.9 MW and is powered by a built-in energy CAP system. This beam rifle was used by the GM Cannons stationed in Jaburo during the Gryps War.
- BLASH HB-L-03/N-STD Hyper Bazooka
- A general purpose fire support rocket launcher platform for mobile suits. With considerable destructive power owing to the high explosive yield in each warhead, the weapon was primarily used to destroy less maneuverable targets such as warships, satellites, land battleships, bunkers, and buildings.
- Balzac type 380mm Rocket Bazooka
- An optional MS-use Bazooka developed for the GM Series, besides having enhanced accuracy due to the sensor mounted on top of the weapon, it is also lightweight, easy to use and has high shooting performance.
- FADEGEL RGM-M-Sh-003 Shield
- A basic defensive armament used by the Federation's GM type MS. It is composed of a triple honeycomb structure made of Luna Titanium. With the appearance of beam weaponry equipped Zeon mobile suits late in the One Year War, later models of this shield are treated with the recently developed beam coating. The shield can also serve as a weapon container as its back has specialized weapon latches for mounting various weaponry, allowing spare beam sabers and beam spray guns to be carried. Some pilots such as Lydo Wolf, would equip two shields, one for each arm.
- RGM*S-Sh-WF/S-00109 Shield
- Mounted on the forearm, this small, light shield is commonly used by the Gundam Ground Type and GM Ground Type. Constructed of Luna Titanium alloy, it is designed to primarily protect the cockpit and other critical areas, and as such has a different form than the RGM-M-Sh-003 model. Additionally, it can be used as a close range striking weapon in mobile suit combat. Furthermore, through lodging the spikes at the tip into the ground, the shield can serve as a free standing frontal defense. This also allows the mobile suit to use both hands to hold large caliber weaponry and maintain a stable firing position.
Initially only six RGC-80 GM Cannons were produced and fielded as part of the Earth Federation Forces's campaign to retake the North American continent. By the time the Earth Federation Forces had recaptured California Base from the Principality of Zeon forces on North America's Pacific Coast, the GM Cannons had proven themselves on the field and was approved for mass-production. Additional GM Cannons were constructed and distributed to various Earth Federation Forces battalions around the Earth to assist in driving the Zeon forces back to space.
By the end of the war, 58 GM Cannons were produced in total. 14 units were assigned to the Revil and Tianem fleets, 6 units were assigned to the North American front, 19 units were assigned to Africa, one of which was given to ace pilot Lydo Wolf and painted in his trademark black custom colors, and 9 units were assigned to Jaburo's defense force. In addition, at least three units were assigned to the Australian front and used by the White Dingo Team. The GM Cannon continued to see active service even after the war and into the Gryps War in UC 0087.