Minigun
From Command and Conquer Wiki
A minigun is the colloquial name for a 5.56 mm or 7.62 mm revolving multi-barrel machine gun. This weapon continues to be used extensively due to its extremely high rate of fire.
One of the key problems in firearms manufacture is heat dissipation. If heat cannot be effectively dissipated, then the barrel of a gun, heated by the rapid detonation of a series of propellant explosions, will heat up to the point of melting, or at the very least burning someone who grabs the barrel. The minigun solves this by having the rotating barrels. A 6 barreled minigun, for example, would rotate one barrel into position, fire the round, and then rotate the barrel to let it cool down while other barrels are rotated into position and fired. This lets extreme rates of fire (~4000 rpm), be maintained for short periods of time, without massively overheating the gun, as each individual gun is fired at a much more reasonable rate of fire (~4000/6 = ~666 rpm). The basic design of the minigun dates back to the American Civil War, when Doctor Richard Gatling invented the gatling gun, powered by an operator's manipulation of a hand crank.
Such an incredible rate of fire means that the weapon is extremely effective at suppression and elimination of enemy infantry, whose maneuverability is hampered through the large amount of shell output. This also means that accuracy is not extremely important. The large number of shell output also gives the minigun a chance to hit extremely maneuverable targets such as aircraft, which would normally be almost invulnerable to ground-based bullet weaponry. For example, the AA gun from Great World War II used a ZSU-23, which is a dual 23 mm cannon. GDI would later similarly employ miniguns for their AA Battery.
There are a number of disadvantages, first and foremost the recoil. Miniguns firing at 4000 rounds per minute generate far too much recoil for any normal human - the Condor personal minigun from the First Tiberium War fired at about 1/6 this rate. The only people who have ever been capable of using full-power miniguns are the Mutant Marauders whose mutations grant the extremely high strength necessary to wield this weapon.
