The M61 Vulcan is a hydraulically, electrically, or pneumatically driven, six-barrel, air-cooled, electrically fired Gatling-style rotary cannon which fires 20 mm × 102 mm (0.787 in × 4.016 in) 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 over sixty years.

The M61 was originally produced by General Electric. After several mergers and acquisitions, it is produced by General Dynamics as of 2000. It is also manufactured under license in Japan by Sumitomo Heavy Industries for Japan's Self-Defense Force and by SNT Dynamics in South Korea