M61 Vulcan Cannon

The  is a weapon featured in Call of Duty: Modern Warfare 2.

In-game
The M61 is only seen twice, in the mission "Of Their Own Accord" and the Spec Ops mission "Big Brother," both times it is mounted onto a Blackhawk helicopter with explosive 20mm rounds.

The gun functions almost identically to that of the M134 Minigun; It is accurate, has a high recoil and and requires spooled before fired, thus it can be pre-prepped in singleplayer by using the aim button.

Trivia

 * The words "GAU 5" are written on the gun.