Minigun

The Minigun is a mounted Machine Gun that appears at certain points of Call of Duty 4: Modern Warfare, Call of Duty: Modern Warfare 2, Call of Duty: Modern Warfare: Mobilized, Call of Duty: Black Ops, Call of Duty: Modern Warfare 3 and Call of Duty: Black Ops II. It is also an obtainable special weapon in Black Ops II.

Call of Duty 4: Modern Warfare
In Call of Duty 4, the Minigun is used by Soap in "Heat" to provide supporting fire for his retreating SAS allies. The Minigun is attached to a downed helicopter (the same helicopter can be seen in the same position in "Safehouse", but the minigun is not present) just past the church. It can also be found in FNG, but the player will not be allowed to use it, since it will just be laying in the weapon's cabinet.

The Minigun can really do a lot of damage because of its high firing rate, but it needs to be cooled off or it will overheat. However, keeping it spooled will not overheat the gun. It's also worth noting that the minigun is highly effective against the helicopters in the mission "Heat", it can normally down one in a short burst and will stop the troops getting off and engaging the player later on in the mission. On Arcade Mode, a helicopter kill is worth 1000 points. A quick spray around will down them all very quickly.

Call of Duty 4: Modern Warfare (DS)
The Minigun is constantly used throughout the helicopter levels in the game, where the player usually needs it to eliminate opposition or take out objectives. Unlike its console counterparts, it cannot overheat and does not need to be spooled up before firing, making it an extremely effective weapon. However, it does lack power and is somewhat inaccurate.

Call of Duty: Modern Warfare 2
The Minigun returns in Modern Warfare 2. It is featured far more often than in Call of Duty 4 and also now has a much shorter and more realistic spooling time. It can be seen in the single player mission "Team Player" mounted on a Humvee. It is also seen on various helicopters. The new Sentry Gun, available in the campaign, Special Ops and Multiplayer, also uses the M134. Additionally, in the mission "The Enemy of My Enemy", it is seen mounted to black SUVs used by Shadow Company.

The HMMWV-mounted M134 is far more inaccurate than the other implementations, firing in a wide, but consistent circular spread; the miniguns mounted on helicopters fire with a much tighter spread.

In Multiplayer, the minigun appears in the multiplayer maps Skidrow, Wasteland, Karachi, Rundown, and Overgrown, replacing the M249 as the standard stationary gun due to balancing issues, due to players in Call of Duty 4 constantly going prone, shooting off a burst, then going prone again automatically due to the way the game handles it. Now, players have to expose themselves for the short spool time before being able to shoot, however the minigun has a higher rate of fire to make up for this. It can be devastating at controlling choke points but the gunner is very exposed and will be a target for enemy snipers.

Using the aim function zooms in and spools the gun barrels without firing, eliminating the "warm up" time. The word "GAU 4" can be seen on the top.

Call of Duty: Modern Warfare: Mobilized
The minigun reappears in Modern Warfare: Mobilized as a usable support weapon. Like in the previous Nintendo DS game set in the Modern Warfare era, it can only be used in helicopter levels. Unfortunately, the only helicopter level is "Helicopter Insertion", so its use is limited. It is now much more powerful, though not as powerful as on the consoles and PC. Luckily, its accuracy has been increased by a large amount, allowing nearly all of the bullets to focus on the designated target, compensating for its low damage (for a minigun).

Call of Duty: Modern Warfare 2: Force Recon
The minigun appears in Force Recon as a support weapon used by the player. Like in NDS installments, it is only used in helicopter based missions.

Call of Duty: Black Ops
The Minigun returns in Black Ops, and is used as one of the helicopter's weapons in Redemption. The minigun is also used in the Chopper Gunner. The minigun is not able to be used directly as a stationary platform, but can be used when mobile by use of the Death Machine.

Call of Duty: Modern Warfare 3
The M134 returns in Call of Duty: Modern Warfare 3.

Campaign
In the end of the mission "Black Tuesday", a M134 is mounted on a UH-60 Blackhawk and was manned by Frost to defend the helicopter from three enemy Mi-24 Hinds. Frost later uses one mounted on Rhino 2 in "Goalpost", after Rhino 2's gunner is killed.

Multiplayer
In the multiplayer map Bakaara, there is a mounted minigun on the crashed UH-60 Blackhawk located near the port area. Miniguns are also seen scattered throughout Liberation.

Call of Duty: Black Ops II
The Minigun appears in Black Ops II in Campaign where it can be unlocked after completing 5 challenges in "Judgment Day" along with the Death Machine. It is the Black Ops Death Machine model, and works in precisely the same way.

During "Achilles' Veil" if the player chooses to have Farid attack Menendez there will be a brief interlude where Section uses a minigun mounted on a US VTOL; this is the Black Ops Chopper Gunner minigun model without the belt box.

Trivia

 * The minigun uses the same reticle as the original game's MG42.
 * In multiplayer, if the player uses a mounted minigun while wielding any sniper rifle, the player can hold their breath while zoomed in with the minigun. However, while it does not affect the player's accuracy, it does remove the minimap from the corner of the screen.
 * If the player does not get off the minigun in "Heat" when Captain Price orders him to, an enemy grenade will be thrown directly where the player is and will blow them up.
 * In Call of Duty: Modern Warfare 2 multiplayer and Call of Duty 4, there is no hand on the minigun in first person.
 * In Call of Duty: Modern Warfare 3 multiplayer, if you aim in on the minigun with the XM25 equipped, the XM25's HUD will show up and still show range, but not mark.
 * In Bakaara in Call of Duty: Modern Warfare 3, the gun model on the crashed helicopter is lifted directly from Call of Duty 4. Since the FOV in Modern Warfare 3 is larger, it is very easy to see there are no player character hands on the grips.
 * In Black Ops II, if the player equips a minigun for "Old Wounds" and rides the horse with it equipped, Mason will hold it one-handed. This shows that the side grip is actually L-shaped since the part normally hidden by the character's left hand is not present at all.
 * With the FOV set to 80 in the PC version of Black Ops II the minigun model is slightly too small for the screen and the "ends" of the model at the bottom and right of the screen can be seen when moving.
 * The minigun will spool up quicker than usual if aiming down the sight. Nothing happens to rate of fire or power at all.