An F-35A fired 181 rounds from its four-barrel, 25 mm GAU-22/A gun during a ground test at Edwards AFB, California, on 14 August 2015. The gun is mounted in the F-35A’s left wing root with a hinged cover over the muzzle. The F-35 Integrated Test Force is scheduled to complete ground gun testing in August 2015 and start airborne testing later this year. The F-35 gun testing began 9 June and the number of rounds fired was gradually increased until the 181 rounds in the magazine were fired in one burst. F-35 flight sciences aircraft AF-2 underwent instrumentation modifications and used a production version of the GAU-22/A gun for the tests. The aircraft used PGU-23/U target practice rounds that do not explode on impact.
