Watch an F-35A fire 181 rounds from its four-barrel 25mm Gatling gun embedded in the left wing

F-35 fired its embedded gun at full capacity.

The F-35 Integrated Test Force has just released an interesting video showing the 181 round gun burst of the 25 millimeter Gatling gun embedded in the F-35A’s left wing root.

The video was filmed during a ground test at Edwards Air Force Base, Calif., Gun Harmonizing Range on Aug. 14; initial shots were fired on Jun. 9 and ground testing should be completed by the end of this month. Airborne testing is to start in the fall and at the end of the firing campaign the gun will be operative by 2017.

According to LM, the F-35 flight sciences aircraft, AF-2, underwent instrumentation modifications and used a production version of the GAU-22/A gun to achieve the full capacity of 181 rounds: along with practice PGU-23/U target practice rounds (which do not explode on impact) software to replicate being in flight was uploaded to the aircraft to conduct the test.

The F-35 GAU-22/A gun has been among the most controversial topics lately: some criticised the fact that the Joint Strike Fighter’s gun can only hold 181 25mm rounds, fewer than the A-10 Thunderbolt’s GAU-8/A Avenger, that can hold some 1,174 30mm rounds.

Interestingly, the gun is hidden behind closed doors, to reduce the plane’s RCS (radar cross section) and keep it stealth, until the trigger is engaged.

While the F-35A will be equipped with an embedded GAU-22 gun, the B (STOVL – Short Take Off Vertical Landing) and C (CV – Carrier Variant) variants will carry it inside an external pod capable to hold 220 rounds.

Image credit: F-35 Integrated Test Force


About David Cenciotti
David Cenciotti is a journalist based in Rome, Italy. He is the Founder and Editor of “The Aviationist”, one of the world’s most famous and read military aviation blogs. Since 1996, he has written for major worldwide magazines, including Air Forces Monthly, Combat Aircraft, and many others, covering aviation, defense, war, industry, intelligence, crime and cyberwar. He has reported from the U.S., Europe, Australia and Syria, and flown several combat planes with different air forces. He is a former 2nd Lt. of the Italian Air Force, a private pilot and a graduate in Computer Engineering. He has written five books and contributed to many more ones.


  1. Is it just me or do they have more than 181 rounds of ammo at the end. At 3,300 rpm they should have emptied that magazine at 3-1/2 seconds give or take a little bit for spool up time but it’s going for 16+ seconds. Did they turn down the rate of fire or feed from an external source maybe because the video doesn’t look to be running at any slow speed.

    • Most of the footage is in slow motion. It appears the first images are at or near full speed.

    • I’ve timed the first sequence and get 07 seconds to 10 seconds, so your numbers are in agreement with my “ball park” readings. Sometimes, I sneeze longer than that!

    • Yeah I’m not sure whats up here, tarp flutter does look real time so I think they may have hooked up the magazine feed to a separate box. But then again, this video is supposed to be about testing the bird’s full RPM so they may loading more rounds to test further possibilities of malfunction.

      But: “While the F-35A will be equipped with an embedded GAU-22 gun, the B (STOVL – Short Take Off Vertical Landing) and C (CV – Carrier Variant) variants will carry it inside an external pod capable to hold 220 rounds.” – This may be whats inside the above shown F-35, an external pod fixed to the already existing internal ammo supply which would make sense due to the video showing a much larger amount of available ammo being thrown. Gothamite estimates a 181 round magazine being empty in 3 & 1/2, by more than doubling the ammo capacity would fit the video clip would come closer to what we’re counting in our heads. So me thinks a pod was added to this test bird.

      Then again why have an external pod at all? WW2 introduced some gun pods on their planes but that wasn’t really practical since it created drag and if it was an external gun, it had to be calibrated often… but an AMMO pod? Could the F-35 R&D group actually have listened to the people complain about the dismal ammo capacity but couldn’t fit it into the frame?

      So where would the “ammo” pod be located, is drag a problem, stealth seems a non-issue if the same stealth material is applied. Anything else I might have missed to bring up?

      • My thoughts weren’t a pod just that the magazine was hooked up to an external magazine just for testing so that more than 181 rounds could be fired. There’s no talk of an external ammo pod for this so I wouldn’t guess there being one here.

  2. Did you notice how much flutter that was on that door? I can see that door becoming a maintenance issue really quick.

  3. One thing which puzzles me it’s the way how cannon covers are opened. I have strong feeling that they will be torn away by the airflow, especially lower one.

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