Minigun

On occasion, a mounted Minigun is available for defending intense, stand-off areas. It has a small windup time but once it starts firing, it becomes one of the best support weapons of the game. The gun is very powerful but can lose its accuracy at longer ranges. It is bolted to the floor so it cannot be moved, only swiveled in an 180 degree arc in front of the gun. It has infinite ammo but can overheat; this is shown as the minigun's barrel quickly glows red, as well as the emission of smoke. This smoke also impairs your vision, causing you to have a harder time shooting accurately. However, this is not an imminent signal of the minigun jamming, as it takes 20 seconds of continuous firing before overheating. The duration of the time it takes the minigun to cool down is the same as it takes the gun to turn completely into a halt.

Tactics

 * Always have a buddy covering your back, because without being able to rotate the weapon 360°, you are vulnerable from behind while using it.


 * Aim for the masses or the mini-bosses. Don't bother shooting at the one or two infected stragglers if, for example, there is a hunter in clear sight.  Your gun can take out enemies the fastest in close quarters.  Use it to trim their numbers or take out the big guys.  Let your non-mini-gun wielding friends take down the stragglers.


 * When shooting into masses of infected, keep an eye on where your fellow survivors are by looking for their colored outlines. There's nothing worse than getting gunned down by your own ally.


 * When fighting a tank, aim for the concrete that he throws at either you or the other survivors, as it can be destroyed before it lands.


 * Even when no infected are present, you should constantly tap the fire button. This will keep the barrel spinning, and eliminate the long wind-up time when a horde suddenly comes at you.


 * The minigun also acts as a bait for tanks in co-op mode, allowing someone to distract the tank with the minigun while his teammates pour lead into the tank.


 * The minigun does not have vehicular properties, meaning you still can be dragged by a smoker or pounced on.

Trivia
A machine gun has a repeating action that chambers, fires and ejects each round. A minigun actually loads ammo directly into the barrels, and the rounds are fired, loaded, and ejected at certain points through its rotation. It is completely electronic and unable to fire without an external power source.
 * The rate of fire displayed by the in-game model, roughly 40 rounds per second, would be considered tame in the realm of modern gattling-pattern weapons. Many can be adjusted to fire up to 100 rounds per second, especially those mounted on aircraft. Even though the rate of fire in-game may seem excessive, it is not all that wearing on the weapon, as each barrel would fire roughly 7 rounds per second, less then some of the hand held weapons in-game.
 * The weapon is sometimes called a mounted machine gun, despite the fact that it has multiple rotational barrels.
 * the fact that these guns are in the various areas hint at how desperate the military must have been; any regular machine gun would've been able to do the job with less maintanence, not need a power supply, and be easier to source. Likely, the military set these up to deal with mutations among the infected like the tank.

Glitches
Be careful though, you will kill yourself a lot experimenting with this glitch, with much lulz.
 * Meleeing the gun repeatedly and jumping onto the minigun will launch the player a certain distance, dependent on the number of times stricken. By using this glitch, it is possible to skip decent sized chunks of many maps, including the forklift crescendo in Death Toll and the door in No Mercy, as well as get to out-of-reach places. This glitch will work with any of the miniguns found in the game. The number of times you melee it has an effect on the power of the launch. The way you're facing while you're launched has an effect on the direction of which you are thrown. From which direction you melee it also seems to have some effect on direction, and hitting the gun from the left seems to launch you straight forward.
 * Fiddling with your flashlight while using the minigun sometimes causes the flashlight sound to loop at a high speed.