Editing GAU-12 Equalizer (section)

==Uses==
[[File:AV-8B Harrier taking off in Sierra Leone - May 2006 (Defense Visual Information Center, USMC, USDoD) CROPPED.jpg|thumb|right|An AV-8 Harrier II; the two pods on the belly of the aircraft hold the cannon (port side, visible hole) and ammunition (starboard side).]]

The current principal application for the Equalizer is the [[AV-8 Harrier II]]s of the [[United States Marine Corps]], [[Italian Navy]] and [[Spanish Navy]]. The Harrier II carries the Equalizer system in a pair of detachable pods mounted on the fuselage underside, with the cannon in the port pod and 300 rounds of ammunition in the starboard pod, fed through a bridge at the aft ends of the pods that also contains the drive system for the gun (unlike previous Harriers which used dual cannons, with each pod containing a [[30 mm caliber|30mm]] [[ADEN cannon|ADEN gun]] and its own ammunition supply). The complete installation, which includes a double-ended feed system that returns empty cartridges to the [[Magazine (firearms)|magazine]], weighs 900&nbsp;lb (410&nbsp;kg) empty and 1,230&nbsp;lb (560&nbsp;kg) loaded. The detachable pods are located and shaped to be interchangeable with the usual ventral strakes or fences under the Harrier, both serving to help trap a cushion of high-pressure air under the aircraft to add lift while in hover mode. The strakes can easily be removed and the pods attached in their place, serving the same function while adding useful firepower.{{citation needed|date=November 2017}}

[[Royal Air Force|RAF]] and [[Fleet Air Arm]] Harriers did not adopt the Equalizer for their [[BAE Harrier II|Harrier GR7]] and GR9s. The British had originally planned a pair of '''ADEN 25''' guns (using the same ammunition as the GAU-12/U, but based on the 30&nbsp;mm [[ADEN cannon]]). That gun was canceled in [[1999 in aviation|1999]] after protracted development problems, and British Harrier GR7/9s were without gun armament until retirement.{{Citation needed|date=June 2007}}

The Equalizer is also used in the [[Lockheed AC-130|AC-130U Spooky]] [[gunship]], where one cannon is mounted on the port side, and the [[United States Marine Corps|U.S. Marine Corps]] [[LAV-25|LAV-AD]] air-defense vehicle. Other applications have been planned for the GAU-12/U, including a mounting for the [[AH-1 Cobra]] [[attack helicopter]].

The Equalizer was also used as the basis for the '''''Sea Vulcan 25''''', a turret mounted gun for naval ship self-defense, although not as a [[Close-In Weapon System]], as the gun was not automatic nor did it use radar tracking. Instead the gun was manually aimed using a digital gun sight and fire control. Sea Vulcan consisted of a 540-round helical drum magazine, a one-piece aluminum turret that can be opened with just a screwdriver, and the main gun. One unique advantage of the system was that it was capable of operating independently of ship's power; the gun and ammunition magazine were powered by a {{convert|3,000|psi|MPa|abbr=on}} [[pneumatic actuator|pneumatic drive]] and the turret motor by twin [[lead–acid battery|lead–acid batteries]].

Intended as a higher-firepower alternative to conventional deck-mounted machine guns and cannon, the weapon employs the Navy's Mk&nbsp;24 target designator and laser range finder for enhanced accuracy. The gun was developed in the mid-1980s as a cost-effective protection for ships smaller than [[frigate]] or [[corvette]] or patrol boats, but did not enter this service.

The GAU-12 was utilized as the principal armament for the [[Scaled Composites ARES|Rutan ARES]].

The four-barrel GAU-22 is carried internally by the F-35A (the [[CTOL]] version of the F-35) on the port side of the fuselage, with 181 PGU-47/U APEX rounds. In contrast, the F-35B [[STOVL]] and C [[CATOBAR]] aircraft mount the GAU-22 in a stealthy external [[gun pod]] under the fuselage, together with 220 rounds.