Watch This: F-35B Fires GAU-22 External Gun Pod in Flight

May 18 2017 - 42 Comments
By Tom Demerly

New Caliber Gun Provides Close Air Support Capability for U.S. Marines.

The U.S. Marine Corps Lockheed Martin F-35B Lightning II Joint Strike Fighter has completed the test firing of its externally mounted General Dynamics GAU-22 25mm gun pod.

The final aerial test firing took place on May 8, 2017 and was conducted by The Salty Dogs of Air Test and Evaluation Squadron (VX) 23’s Integrated Test Force (ITF) at Naval Air Station (NAS) Patuxent River.

Of particular interest in the video just released (that includes footage from several different sorties) is the variety of additional external stores carried on the test F-35Bs. The aircraft are shown with a version of the AIM-9X Sidewinder air-to-air missile and, in a separate flight, with what appears to be a 500lb laser guided bomb possibly a version of the GBU-12 Paveway II.

The new General Dynamics GAU-22 25mm gun pod uses a unique four-barrel configuration that was developed from the highly successful five-barrel, 25mm GAU-12/U gun also built by General Dynamics. The new GAU-22 gun, carried internally on the USAF F-35A variant and in the external pod for the U.S. Marines’ F-35B is and U.S. Navy F-35C is more than 40 pounds lighter and requires 20 percent less overall space than the earlier GAU-12, 5-barrel 25mm gun. The new GAU-22 weapon has a reported rate of fire of “up to 3,300 rounds per minute”. The rate of fire of aerial guns is often reported as “up to…” since the gun can take several seconds to achieve its maximum rate of fire because of the weight of the rotating gun barrels.

The GAU-22A Gun Pod. (Image credit: LM)

The successful in-flight test firing of the 25mm gun pod (started at the end of February), specifically on the U.S. Marine Corps F-35B, somehow addresses questions over the F-35 program’s ability to perform the close air support mission. Several analysts have expressed concern over whether the F-35 is suited for the close air support mission and is a suitable substitute for the CAS-specific A-10 Warthog.

Generally speaking it’s wrong to compare the F-35 with any other asset that was designed to perform a specific mission: the A-10 was built around a unique 30mm cannon nearly as long as the aircraft’s entire fuselage that was intended for the anti-armor close air support (CAS) mission.

While this initial test-firing does not resolve questions surrounding all of the F-35B’s close air support capabilities it is another successful step forward in the program’s progress. At least it can use the gun if called into action during a CAS mission!

The F-35 GAU-22/A gun has been among the most controversial topics: some criticised the fact that the Joint Strike Fighter’s gun can only hold 181 20mm rounds, fewer than the A-10 Thunderbolt’s GAU-8/A Avenger, that can hold some 1,174 30mm rounds.

Moreover, although it was designed with LO (Low Observabity) characteristics, the external pod degrades the F-35’s radar cross section making the 5th generation aircraft more visibile to radars. Still, this should be acceptable for the scenarios where the U.S. Marine Corps F-35B will be called to carry out CAS missions.










  • Paul Rain

    181 20mm rounds, fewer than an F-16 with 500 odd 20mm rounds, fewer than the F-22 with 480 20mm rounds, fewer than the F/A-18 with 410 20mm rounds.

    In other words, it’s garbage.

    • chris mcbride

      In other more educated words it is more accurate and more capable then it’s predecessors.

    • InklingBooks

      Ah, but it’s got the One Ring of invisibility. That’s all that matters. So what if it runs out of ammunition. No one can see it. It can sneak up behind enemy soldiers and go “boo.”

      • Ty Harris

        Don’t knock it. Being able to show up anywhere in the world, with no warning, in any type of threat environment and do whatever you want without the enemy being able to detect you, lock on to you, or hit you sounds like a good thing to me. 4th gen aircraft are going to be increasingly less survivable against modern networked anti-aircraft radars. Stealth is where you start and you build from there. These F35’s are quickly heading towards cost parity now thanks to foreign sales lowering unit costs and their overall capabilities are not even comparable to 4th gen aircraft. Killing tanks is not really what the F35 is designed to do. It’s never going to replace the A10. That was a bridge too far. But that fact doesn’t mean the F35 is not exactly what we need. It will form the backbone of the airforce and marine aviation for the next 40 years and will get better and better with each software upgrade.

    • Trapperpk

      Does this means the F-35 has 181 wing mounted 20 MM rounds and 181 belly mounted rounds totaling 362, 20 mm rounds on board? The belly gun pod sounds like a plug and play field configuration attribute when the need changes to a CAS environment. The gun pod appears to install on and off with little mechanical effort and will be used as a mission feature for ground attack. F-35 “Good at all things but master of none.” ?

    • chris sullivan

      Couple of points to consider-
      1. 180 is internal cannon capacity, used only on F-35A. This post is about the pod being tested on the F-35B. The pod carries about 20% more shells- 220. The F-35C will also use the gun pod. By the way, F-18 gun capacity is about 575, not 410 rounds.

      2. The 25mm shell is WAY, WAY more powerful than 20mm, don’t let the mere 5mm difference in shell diameter fool you. 1 hit from a 25mm could easily fatally damage a fighter, considering increased blast/frag as compared to 20mm. Try a Google Search of the Apex 25mm round, it might cheer you up to see the ginormous holes & frag damage done to a F-5 test article by a single round.

      3. Before you write off the F-35, you might want to ask how many shells other fighters are carrying these days. Typhoon- 150 27mm, Rafale- 130 30mm, Gripen- about 150 27mm. So, by your logic, the Eurofighter countries (UK, Germany, Italy,Spain), plus France (Rafale) & the Swedes (Gripen) are all morons too. Good to know!

    • Chugs 1984

      So tell me in the thousands of CAS missions completed how many of them used guns, be it the A-10, F-16 or F-18?

      In the last 40 years when was the last time an aircraft flying CAP used its guns compared to missiles?

    • ratherdrive

      Rather useless against armor. Not to mention, it can sometimes take 181 rounds to even “find” the armor, before strikes begin to occur..

    • PikaJew

      It has 30 mm rounds

    • drinking12many

      Most CAS isnt done with a gun and even the A-10s 30MM wont penetrate a lot of modern armor out there.

      • Pacemaker4

        describe the armor and the platforms it wont penetrate Please.

        • drinking12many

          The T-90A’s composite armor was specifically designed to counter the GAU-8’s API rounds. They wouldn’t get close to penetrating the turret roof in a controlled environment let alone the real world.

          • Pacemaker4

            what am I missing the A-10 has the GAU-8 which fires 30mm rounds
            and the F-35 uses the GAU-22 which fires 25 mm.

    • SmoovyBRad

      It’s a 25mm gun, it doesn’t need nearly that much ammo. The difference in weight between a 25mm round and a 20mm is also significant. The MiG-29 (which before you say it is not an air superiority fighter but a tactical multi-role) carries a 30mm cannon with only about 150 rounds, and that is an aircraft heavily used by many forces for CAS, and I don’t think I’ve really heard someone call the -29 “garbage”. For a more “american” comparison, if you will, the A-4 Skyhawk (a dedicated ground attack aircraft) had two 20mm cannons with only 100 rounds each, and that aircraft was designed in the 40’s/50’s and is still in service today, so please, stop.

    • Renato Dallarmi

      But but but.. I am sure they are stealth rounds, tiene Emmy won’t even know they are coming…..

    • stb

      I think F-35 should have 2 engines & an aerodynamic design capable for dogfight maneuverability, beyond stealth capabilities. Then it would become the absolute hit!!!

    • rcerke79

      Fewer than the A-10 with 1350 30mm rounds.

    • Jimmie

      True but the 20mm on any of the 35’s was and is only meant for last ditch air to air defence when a rocket missile etc isn’t feasible or unavailable.

    • mwgimpy

      Eurofighter Typhoon -1 × 27 mm Mauser BK-27 revolver cannon with 150 rounds, Dassault Rafale – × 30 mm (1.18 in) GIAT 30/M791 autocannon with 125 rounds, Saab JAS 39 Gripen – 1× 27 mm Mauser BK-27 Revolver cannon with 120 rounds, Mikoyan MiG-35 – 1× 30 mm GSh-30-1 cannon, 150 rounds, Sukhoi Su-37 – 1× 30 mm GSh-301 internal cannon with 150 rounds.

      • Rohan Bussell

        The europeans/russians dont value cannon armament and strafing in any of their fighter designs.
        The war on terror has shown how valuable gatling cannons are in the CAS role…great for morale, controllable and effective.

  • billybongo

    I see that the aircraft is coal-fired from the smoke puffs, heating up the steam-driven engine. The enemy is frightened by the sound of a train whistle going “Choo Choo!”

  • Särimner

    A multi-multimillion dollar stealth-fighter performing CAS. In broad daylight or even at night at close range. How do you think???

  • ScoobiJohn

    181 rounds is kinda pathetic – though i expect since the f-35 is supposed to do ‘close’ air support from high altitude with guided munitions suppose it will rarely get used – what this gun needs is laser guided bullets – if every bullet was a guaranteed hit wouldn’t be so bad – but dont know if they are even close to being past prototype stage

  • Andrew Tubbiolo

    Why have the gatling gun if the pod can only hold 181 rounds? To add to that question it looks like they’ve set the firing rate to a very low speed taking away the benefits of a gatling type gun. Better off going to a cannon and then you could hold more rounds in the enclosure. Maybe they wanted the choice of fast or slow rate, but with that small magazine of rounds, that system better not miss.

  • toady

    I think you’re being unfair about the benefits: compromising stealth; increased drag; pylon flexing reducing targeting accuracy; and extra airplane weight to engineer that hard-point to that flush pylon.

    But none of those benefits matter because Lockheed hit a design milestone.

  • Ilya Kurenkov

    Gun pod on a stealth plane.. I hope, that F-35 case will be included to all aeroengineering studybooks as a perfect example of how combat plane should not be developed. All and every mistakes were done, and tons more are still to come.

  • Rob Annable

    A rate of fire (up to) 3300 per minute means (up to) 55 rounds per second. So with a capacity of 181 rounds, it can carry enough for just over 3 seconds of shooting. *slow claps*

    (unless my maths is massively wrong)

  • Cocidius

    Bravo USMC! It’s only taken 16 years of development and $500 billions dollars of funding to duplicate an operational capability that every other aircraft tasked with CAS has been able to do for the last 50 years.

  • Black Eagle

    Wow, that gun is so stealth that it doesn’t even make any noise.

  • JMurman

    The limited amount of ammo carried versus the huge monies invested should be a non starter to any thinking person. However we are not talkingn about a rational thinking person, but a political football that both military complex and politicians are drooling over.

    • Ilya Kurenkov

      Please be sure there are very, very rational thinking people behind this project. You just have to look at F-35 from another angle. This is absolutely brilliant project, aimed for making money. Lockheed Martin earns tons of bucks of F-35, employ thousands of people and shows excellent financial results year by year. The only thing they have to do is to continue development of F-35, the longer the better. They are simply not interested in finishing this project.
      So this is just a matter of priorities: you expect to receive capable combat aircraft, LM expect good financial reports in years to come.

      • Uniform223

        “The only thing they have to do is to continue development of F-35, the longer the better. They are simply not interested in finishing this project.”

        > oh you mean like Sukhoi’s PAKFA project? How many aircraft do they have? 9? After 17 years of advertising, rhetoric, and propaganda all they have to show for are 9 aircraft and one with a new paint job. *slow clap, slow clap*

        • Ilya Kurenkov

          You confused PAK FA with F-35. May I remind you that first flight of what later became F-35 happened back in 2000, 17 years back. First pre-production F-35 was delivered in 2010. All we have after 17 years of advertising, rhetoric and propaganda are 200 of airframes with endless iterations of structural modifications and software versions. Out of these 200 airframes only 12 declared IOC.
          The very first PAK FA took off in 2010, and after 7 years of development they have 8 test machines participating in various tests and an airframe, T-50-9, which is (almost) identical to the version which will go to full scale production.
          Much more mature approach, I would say. And much more cost effective.

          • Uniform223

            Let’s do some corrections because your assumptions are WRONG.

            “I remind you that first flight of what later became F-35 happened back in 2000, First pre-production F-35 was delivered in 2010”

            > though you are correct that the x-35 flew in 2000. That was for the dem/eval between the lockheed Martin design and Boeing’s x-32. Though this is not the start of the JSF Program, this is where it really started to come to light. The X aircraft that flew having little to nothing in common with current the aircraft. The first preproduction F-35A was introduced in 2006, F-35B in 2008, and F-35C in 2010.

            “All we have after 17 years of advertising, rhetoric and propaganda are 200 of airframes”

            > that is still 191 MORE airframe then the PAKFA. Though currently that number is 231 so really that is 222 MORE aircraft aircraft than the PAKFA. So if we’re going to use simple math that would mean on average there are 21 F-35s produced per year compared to 1.28 PAKFAs produced per year.

            “with endless iterations of structural modifications and software versions”

            > Most of not all structural modifications are either approved, in the process of being applied, or completed. Only the F-35C is left in concerns with its landing gear. The aircraft has the highest use of software for any current aircraft. Most any future update/upgrade to the aircraft will depend heavily on the software code. Even the F-22 is still having software updates/upgrades. So what is your point?

            “Out of these 200 airframes only 12 declared IOC.”

            > The USMC currently has two squadrons of F-35B and the USAF currently has one. So that would mean the number of total aircraft in IOC is closer to 36. That is 36 more aircraft than the PAKFA ebicb currently have zero ( none, nikto, zilch, nada). Of course the current 231 that encompasses all variants of the F-35 and users.

            “The very first PAK FA took off in 2010, and after 7 years of development”

            > development is still going on as there is actual production or service model that has been delivered.

            “8 test machines participating in various tests and an airframe, T-50-9, which is (almost) identical to the version which will go to full scale production”

            > yes… They are all test machines you have that right. Almost? What about the engines, avionics, radar and weapons? The only test I’ve seen concerning weapons was on a PAKFA mock up during its cannon.

            “Much more mature approach, I would say. And much more cost effective.”

            > well that is just your opinion and doesn’t reflect that facts of reality.

            Here is a lockheed martin advertisement called “by the numbers”.


  • cromicacid

    Only the F-35A has an internal gun. Only has 180 25mm rounds……just enough for maybe 3 second squeeze on the trigger.

  • WpnsLoader175

    I am still waiting for my brass from these shoots. Weather was nice and was a good distraction from normal to go out to there and hand crank ammo in. This has just enough ammo for one good gun run, not going to help much in CAS. A-10 fires 100-300 rounds, depending on requirements of the fight, of much larger 30mm HEI rounds. However the 20mm rounds are next to useless, so at least the few bullets it does have are halfway descent.

    • Uniform223

      1 250lbs guided HE multifunction (airburst, impact, and penetrating) guided munition that can be accurate within 1 meter, is more effective then 100 rounds of 30mm HEI rounds. The 25mm for the F-35 that will most likely be computer controlled is said to be more accurate then the former and fires armor piercing explosive rounds. A 25 or 50 round burst would give any soft or lightly armored target a bad day. In either case I wouldn’t want to be on the receiving end of either of them.

      • WpnsLoader175

        Well the 250lbs SDB is a good weapon, especially the newest versions. But, sometimes area of effect is key cause even the guy on the ground doesn’t know where the bad guys are. So you have to saturate the area with powerful weapons. Also, the “frag zone” of a SDB is still greater than a 30mm HEI run. Also, and I know this from being in the CAS community for more than 14 years, sometimes GPS grids just can’t be established and the guys in the ground need weapons NOW, and “That treeline over there” Is their targeting. So we will always need gun. I have worked on, loaded both systems, the GAU-22 is a baby compared to the GAU-8 monster.

  • Uniform223

    The AV-8B Harrier is the primary fixed wing CAS aircraft for the USMC and it uses a 25mm gun pod and doesnt have that many rounds over the GAU-22A of the F-35. I dont hear people complaining about the Harrier or the FACT that all variants of the F-35 carries more bullets then any European or Russian fighter aircraft.

  • Rohan Bussell

    “… low-collateral bombs…”
    Thats not what Ive read. The implication of your post is that dropping bombs is always preferable, reality shows clearly thats not the case.