Demonstration of the 30-mm GAU-8 Avenger (A-10 Thunderbolt II Main Gun) and the 20mm M61 Vulcan mounted on Phalanx CIWS, C-RAM during test fire / training. The M61 Vulcan is a hydraulically or pneumatically driven, six-barrel, air-cooled, electrically fired Gatling-style rotary cannon which fires 20 mm rounds at an extremely high rate (typically 6,000 rounds per minute). The M61 was originally produced by General Electric. After several mergers and acquisitions, it is currently produced by Gener