RX-77-2 Guncannon

Brief Description

The RX-77-2 Guncannon was a mid-range support mobile suit developed by the Earth Federation as part of Operation V during the One Year War. Designed to support the RX-78-2 Gundam in combat, the Guncannon combined heavy armor with a pair of powerful shoulder-mounted cannons and beam weaponry. While slower and less agile than the Gundam, its durability and long-range firepower made it highly effective at providing covering fire and engaging enemy forces from a distance.

Development Hisory

The RX-77-2 Guncannon was developed by the Earth Federation Forces during the One Year War as part of Operation V, the Federation’s secret program to develop mobile suits capable of countering the Principality of Zeon’s MS-05 Zaku I and MS-06 Zaku II. The program was overseen by Federation engineer Tem Ray and ultimately produced three major prototype machines: the RX-75 Guntank, RX-77 Guncannon, and RX-78 Gundam.

Development of the Guncannon represented an important step between the Guntank and the more advanced Gundam. While the Guntank was primarily designed as an artillery platform, the RX-77 project sought to create a fully humanoid mobile suit capable of providing direct mid-range fire support while retaining greater battlefield mobility. Early RX-77 prototypes were used to determine how much armor could be carried without excessively reducing the machine’s mobility, eventually leading to the finalized RX-77-2 Guncannon.

Because the Guncannon was expected to operate closer to enemy mobile suits than the Guntank, its design placed a heavy emphasis on protection. The machine was constructed using Luna Titanium alloy, giving it exceptional durability for a mobile suit of its era. This protection came at the expense of some mobility, but the Guncannon was not intended to fight in the same close-range role as the RX-78-2 Gundam. Instead, it was designed to support other Federation units with sustained fire from its twin shoulder-mounted cannons.

The Guncannon also incorporated several technologies shared with the other Operation V mobile suits. Most notably, it used the Core Block System, allowing an FF-X7 Core Fighter to serve as the mobile suit's cockpit and escape system. Its reactor output was also sufficient to operate a handheld beam rifle, giving the Guncannon significantly greater offensive flexibility than a conventional artillery platform.

Unlike the RX-78-2, however, the Guncannon was not primarily designed around close-quarters combat. Its heavy armor, powerful shoulder cannons, and beam rifle instead established it as a dedicated medium-range support mobile suit, capable of accompanying more maneuverable units while delivering heavy fire against enemy mobile suits, vehicles, and fortifications.

A total of six early-production RX-77-2 units are described as having been constructed, with three being sent to Side 7 for final testing in August U.C. 0079. On September 18, U.C. 0079, Zeon forces attacked Side 7 while investigating Operation V. Most of the Federation prototypes stationed there were destroyed during the attack, leaving one Guncannon available to be recovered and loaded aboard the White Base. That machine would later become closely associated with Kai Shiden and demonstrate the effectiveness of the Guncannon concept throughout the One Year War.

Although the RX-77-2 itself was too specialized and complex to become the Federation's primary mass-production mobile suit, its combat data and design philosophy influenced later support machines, helping establish the concept of the cannon-equipped support mobile suit within the Earth Federation Forces.

WEAPONS

2 × 240mm Cannons

Mounted on the shoulders and serve as the Guncannon’s primary long-range weapons. They provide heavy fire support against mobile suits, vehicles, and fortified positions.

2 × 60mm Vulcan Guns

Mounted in the head. Mainly used against infantry, light vehicles, missiles, and other lightly armored targets.

XBR-M-79a Beam Rifle

The Guncannon’s beam rifle was developed by BOWA Corporation specifically for use with the RX-77-2. Although its model number suggests otherwise, the weapon is classified as an XBR-L type beam rifle and was designed primarily for long-range precision fire.

Compared with the XBR-M type beam rifle used by the RX-78-2 Gundam, the Guncannon’s rifle was more difficult to handle, but offered superior accuracy and a significantly longer effective range. This allowed the Guncannon to use the weapon in a sniper-like role, engaging targets from great distances.

Early in its development, the rifle could not be used properly due to limitations in the Guncannon’s generator output. These issues were later resolved through modifications carried out at Luna II. The weapon is said to have an effective range of approximately 30 kilometers.

YHI YF-MG100 100mm Machine Gun

Developed by Yashima Heavy Industries, the YHI YF-MG100 100mm Machine Gun became a standard firearm used by Earth Federation ground-based mobile suit forces during the One Year War. The weapon is also identified by the alternate model designation NF·GMG-Type.37/100mm.

The machine gun used a box magazine and featured a folding stock, making it relatively easy for mobile suits to handle while maintaining a high rate of fire. Its barrel used a smoothbore design rather than conventional rifling and required replacement after approximately 3,000 rounds had been fired.

One of the weapon’s greatest advantages was its ammunition flexibility. The 100mm machine gun could fire HEAT (High-Explosive Anti-Tank), APFSDS (Armor-Piercing Fin-Stabilized Discarding Sabot), and HESH (High-Explosive Squash Head) ammunition. This allowed Federation units to select different ammunition types depending on the target and mission requirements.

Spray Missile Launcher

The Spray Missile Launcher was an optional shoulder-mounted weapon system developed for the RX-77-2 Guncannon. It replaced the standard 240mm cannons with a pair of 12-round missile launchers, giving the mobile suit a total capacity of 24 missiles.

The system was designed to unleash a concentrated barrage at close to medium range, allowing the Guncannon to overwhelm enemy units with a large volume of explosive fire. Unlike the precision-oriented 240mm cannons, the Spray Missile Launchers emphasized saturation attacks and area suppression.

The weapon system remained largely in the prototype stage, and it is unclear whether it ever saw confirmed use in actual combat during the One Year War.

Hand Grenades

The Guncannon can also carry hand grenades for use at close range. One grenade is stored inside a secured compartment located on the lower portion of each leg.

Once removed from its storage compartment, the grenade is automatically armed. It uses a fuse lasting approximately five to seven seconds, providing enough time for the Guncannon to throw the explosive before detonation.

Although relatively simple compared with the Guncannon's beam rifle and shoulder-mounted artillery, the grenades provide the mobile suit with an additional close-range weapon for attacking enemy units, fortified positions, or groups of targets.

ARMOR

Luna Titanium Alloy

The RX-77-2 Guncannon was protected by Luna Titanium alloy, the same advanced armor material used by other Operation V mobile suits. Following the One Year War, Luna Titanium would become better known as Gundarium Alloy. The material offered exceptional strength and durability while remaining relatively lightweight compared with conventional armor materials available at the time.

Luna Titanium gave the Guncannon substantially greater protection than most contemporary mass-produced mobile suits. Conventional projectile weapons that could seriously damage ordinary mobile suits were considerably less effective against Luna Titanium armor.

Although Luna Titanium provided outstanding resistance to conventional ammunition, it was not invulnerable. High-powered beam weapons, particularly mega-particle weapons, were capable of penetrating Luna Titanium armor.

As beam weapons became increasingly common later in the One Year War, the advantage provided by heavy physical armor became less absolute. The Guncannon could withstand punishment that would destroy many conventional mobile suits, but a sufficiently powerful beam weapon could still inflict catastrophic damage.

PERFORMANCE/MOBILITY

The RX-77-2 Guncannon was designed primarily as a medium-range fire-support mobile suit, so its development prioritized armor, stability, and firepower over raw mobility. Its heavy Luna Titanium armor and large shoulder-mounted cannons made it considerably heavier and less agile than the RX-78-2 Gundam.Despite this added weight, the Guncannon was still capable of respectable battlefield performance. Its mobility was considered roughly comparable to the MS-06 Zaku II, meaning it was not an immobile artillery platform like the earlier Guntank. It retained enough maneuverability to reposition, follow allied mobile suits, and participate directly in mobile suit combat.

The Guncannon was equipped with rocket thrusters producing approximately 51,800 kg of total thrust. This gave the machine a maximum acceleration of around 0.74 G.

Although this was lower than the RX-78-2 Gundam's approximately 0.93 G acceleration, it was still respectable for a heavily armored support unit.

Its backpack thrusters were also powerful enough to perform short jumping maneuvers under gravity. This allowed the Guncannon to clear obstacles, rapidly change firing positions, and gain limited elevation during ground combat rather than relying entirely on conventional running movement.

The Guncannon is listed with a maximum speed of approximately 78 km/h, reflecting its heavier construction and support-focused design.

It was never intended to chase highly maneuverable enemy mobile suits or engage in prolonged close-range duels. Instead, its mobility was sufficient to allow it to keep pace with battlefield formations while moving between advantageous firing positions.

This represents one of the Guncannon's most important design improvements over the RX-75 Guntank. Rather than being essentially a mobile artillery vehicle, the Guncannon possessed a fully humanoid mobile suit configuration and could maneuver across terrain much more effectively.

The Guncannon's reactor produced approximately 1,380 kW, giving it the same listed reactor output as the RX-78-2 Gundam.

This was an impressive amount of power for an early Federation mobile suit and helped support the Guncannon's advanced sensors, propulsion systems, and eventually its specialized beam rifle.

However, possessing the same reactor output as the Gundam did not mean the two machines had equal performance. The Guncannon had significantly more mass to move, with a maximum weight of approximately 70 metric tons, compared with around 60 metric tons for the RX-78-2.

As a result, more of its available power had to compensate for its heavier armor and equipment.

The Guncannon's greatest performance weakness was close-range maneuverability. Its thick armor and shoulder cannons restricted its agility, and the machine was not normally equipped with dedicated melee weapons such as beam sabers.

It could still defend itself at close range using its beam rifle, head Vulcans, grenades, or even physical attacks, but close combat was not where the machine performed best.

Against faster mobile suits, the Guncannon was better suited to maintaining distance and using its armor and firepower rather than attempting to match the opponent's maneuverability.

VERSATILITY

Although the RX-77-2 Guncannon was developed primarily as a mid-range fire-support mobile suit, its equipment allowed it to perform several different battlefield roles. It could provide artillery support, engage mobile suits directly, perform long-range precision attacks, suppress enemy positions, and defend itself at close range.

This makes the Guncannon considerably more versatile than the RX-75 Guntank. Instead of being restricted mainly to artillery support, the Guncannon possessed the mobility and handheld weapon capability of a conventional mobile suit while retaining heavy support weapons.

With its specialized XBR-M-79a Beam Rifle, the Guncannon could operate as a long-range precision unit. The rifle reportedly had a range of approximately 30 kilometers and offered better accuracy and range than the beam rifle associated with the RX-78-2 Gundam.

Combined with its sophisticated targeting systems, this allowed the Guncannon to potentially function in a sniper or long-range fire-support role, engaging enemy mobile suits before they could close the distance.

The Guncannon's shoulder weapons could be changed depending on mission requirements. Its standard 240mm cannons could be replaced with a pair of 12-round Spray Missile Launchers.

This changed the Guncannon from a precision artillery platform into a saturation-fire unit, capable of launching a large missile barrage against enemy formations at closer ranges.

The ability to change its primary shoulder armament gave commanders some flexibility in configuring the machine for different missions. However, the Spray Missile Launcher remained a prototype system, and its confirmed battlefield use is unclear.

The Guncannon was not dependent entirely on its specialized beam rifle or shoulder weapons. It could also carry the YHI YF-MG100 100mm Machine Gun, one of the standard weapons used by Federation ground mobile suits.

The 100mm machine gun itself was highly adaptable because it could use HEAT, APFSDS, and HESH ammunition, allowing different ammunition to be selected depending on the target.

This gave the Guncannon a more conventional combat option when its specialized long-range beam rifle was unnecessary or unavailable.

COST-EFFECTIVENESS

The RX-77-2 Guncannon was an advanced prototype developed under Operation V, and many of the features that made it so effective also made it expensive and complicated to manufacture.Its construction incorporated advanced systems such as Luna Titanium armor, the Core Block System, powerful shoulder-mounted cannons, sophisticated targeting equipment, and the ability to operate advanced beam weaponry.While these features gave the Guncannon excellent battlefield performance, they were not necessarily economical for a mobile suit that the Earth Federation would eventually need to produce in large numbers.There is no reliable canonical monetary figure for the cost of producing an individual RX-77-2, so its cost-effectiveness has to be evaluated through the Federation's later development decisions.

The Guncannon performed well enough that the Earth Federation did consider mass-producing the design.

However, wartime production requirements ultimately pushed the Federation toward a less expensive solution. Rather than manufacturing the RX-77-2 with only minor modifications, engineers developed the RGC-80 GM Cannon around the existing RGM-79 GM production infrastructure.

The GM Cannon shared approximately 60% of its components with the GM, improving production efficiency, spare-parts availability, and overall cost-effectiveness. The RX-77-2 belonged to the experimental Operation V generation rather than the Federation's emerging mass-production ecosystem. The RGM-79 GM and its variants offered far greater potential for shared components, standardized weapons, replacement parts, maintenance training, and production lines.

The RX-77-2 Guncannon was highly effective, but it was not particularly economical.

Its advanced armor, Core Block System, specialized weapons, and sophisticated equipment created one of the most capable support mobile suits of the early One Year War. Unfortunately, those same features made the design too complicated and expensive to be an ideal mass-production machine.

GALLERY