The M61 Vulcan is a hydraulically or pneumatically driven, six-barrel, air-cooled, electrically fired Gatling-style rotary cannonwhich fires 20 mm rounds at an extremely high rate (typically 6,000 rounds per minute). The M61 and its derivatives have been the principal cannon armament of United States military fixed-wing aircraft for fifty years.
The M61 was originally produced by General Electric. After several mergers and acquisitions, it is currently produced by General Dynamics.
The JASDF F-4EJ Phantom jets have the M61 Vulcan as its machine gun armament.