America’s most expensive stealth fighter carries a gun that every radar can see, and there’s a reason the Marines kept it that way

The F-35 is built around stealth, sensors, and precision, which is why one detail about two of its variants seems so strange at first glance: the F-35B flown by the Marine Corps and the F-35C flown from Navy carriers carry their cannon in an external pod beneath the aircraft.

In a recent Navy Decoded breakdown, the channel’s host described the arrangement as one of the most misunderstood features of the jet, because what looks like an obvious stealth flaw also created one of the aircraft’s most useful mission options.

The host explained that the F-22 Raptor hides its gun inside the aircraft, with a door opening only when the weapon fires, and the F-35A also carries its cannon internally behind a flush panel. But the Marine Corps’ F-35B and the Navy’s F-35C mount the same basic gun externally in a carbon-fiber pod beneath the fuselage, where it can be seen by radar when carried.

That sounds like a contradiction for a stealth aircraft, but Navy Decoded’s argument is that the pod was not simply a mistake. It was a compromise forced by physics, space, and mission demands, and in the Marine Corps’ case, it became a feature worth keeping.

A Lesson From Vietnam That Never Went Away

The host began by going back to Vietnam, where the F-4 Phantom II entered combat without an internal gun because designers believed missiles had made cannons obsolete.

That theory fell apart quickly.

As Navy Decoded explained, early missiles had serious limits. The AIM-9B Sidewinder had to attack from behind, had a narrow seeker, struggled against clouds or the sun, and was ineffective inside certain close ranges. The AIM-7 Sparrow had its own problems, including a minimum engagement range and the need for pilots to maintain radar lock while maneuvering against enemy aircraft.

The host noted that American pilots were also required to visually identify targets before firing over North Vietnam, which often erased the supposed advantage of beyond-visual-range missiles. By the time a pilot knew the target was hostile, the fight had already moved close enough that missiles might not be the answer.

That experience became a lasting lesson in fighter design: even if guns rarely produce modern air-to-air kills, they still matter because their presence prevents an enemy from safely closing into a missile dead zone.

The host framed the cannon as both a deterrent in the air and a final option near the ground, especially for aircraft expected to support troops who need fire quickly and precisely. The Joint Strike Fighter requirement, he said, still called for a gun capable of engaging lightly armored vehicles at range with a defined probability of kill and dispersion standard.

In that sense, the gun survived not because planners expected every F-35 to fight like a World War II aircraft, but because war has a way of punishing designs that assume one weapon will solve every problem.

Why The B And C Could Not Hide The Gun

According to Navy Decoded, the F-35A solved the gun requirement by placing the GAU-22/A internally, but the F-35B and F-35C simply did not have the same space available.

The F-35B is the short-takeoff and vertical-landing variant used by the Marines, and its internal layout is dominated by the lift fan and the three-bearing swivel module that make vertical landing possible. Those systems consume the space where an internal gun might otherwise go.

The F-35C, built for carrier operations, has its own space problem. The host said its larger fuel load and reinforced carrier landing gear leave no room for an internal cannon installation.

The result was a centerline gun pod, carried beneath the aircraft. The F-35B uses the GPU-9/A pod, while the F-35C uses the GPU-8/A, with each pod shaped to match its aircraft’s belly contour.

That is the trade-off. The aircraft gives up some clean stealth shaping when the pod is installed, but it gains a removable gun system that can be carried when the mission calls for it and left behind when stealth matters more.

That flexibility is easy to overlook, but it is central to the argument. The F-35A always carries its internal gun volume. The B and C carry the pod only when they need it.

Inside The Pod

Navy Decoded described the pod as a carbon-fiber shell roughly the size of a bathtub, built around the GAU-22/A, a four-barrel 25mm Gatling gun derived from the GAU-12/U used on aircraft like the AV-8B Harrier and AC-130U gunship.

The host said the gun fires about 3,300 rounds per minute, or roughly 55 rounds per second, with each round leaving the muzzle at several times the speed of sound. The pod carries 220 rounds in a helical feed system wrapped around the gun’s axis.

The ammunition, according to the breakdown, is a semi-armor-piercing, high-explosive incendiary tracer round designed to punch into light armor, detonate, and burn.

The recoil is substantial, around 3,700 pounds of force, and that is where the external design becomes more interesting. The host said the pod is mounted on the centerline station, directly under the aircraft’s main structural spine, allowing the recoil to pass through the hardpoint and into a strong structural beam rather than into delicate stealth skin or internal composite structures.

In other words, the pod does not just hang there. It isolates a violent mechanical force from areas of the aircraft that were not designed to absorb it directly.

The pilot also is not aiming in the old-fashioned sense. Navy Decoded said the F-35’s helmet-mounted display projects targeting information onto the visor, while the radar and fire-control system help calculate the firing solution. A burst controller limits each trigger pull, meaning the 220-round load gives the pilot only a handful of short, calculated bursts.

That detail matters because the external gun pod is not a spray-and-pray weapon. It is a limited magazine attached to a very advanced sensor system, and the practical question is not how many rounds are carried but how many can be placed where they are needed.

Why The Marines Still Need It

The most convincing part of the Navy Decoded argument concerned the Marine Corps, because the F-35B is not simply another stealth fighter. It is also a ship-based aircraft designed to fly from amphibious assault ships that do not have catapults, arresting cables, or the full air wing of a nuclear-powered carrier.

The host used the USS Tripoli as the example, noting that the ship demonstrated the “Lightning Carrier” concept in 2022 by operating a large number of F-35Bs from an amphibious assault ship.

In that kind of scenario, Marines ashore may need close fire support from the aircraft available nearby, not from an A-10 based on a runway or an AC-130 that may not be present. The F-35B can launch from a short deck, reach the fight quickly, use its sensors to find targets through darkness or weather, and deliver precision weapons or gunfire depending on the situation.

The host contrasted the F-35B with the A-10, which carries far more ammunition and remains purpose-built for close air support in permissive airspace, but cannot operate from a ship and is not designed to survive modern contested air defenses. He also compared it with the older AV-8B Harrier, which could operate from ships but lacked the sensor fusion and all-around infrared awareness of the F-35B.

That is the Marine Corps logic in plain terms: the gun pod is not for the first night of a war against dense air defenses, when the aircraft may fly clean and stealthy. It is for the moment after air defenses have been reduced, when Marines need a precise and immediate effect and a bomb may be too much.

There are plenty of debates to have about the future of close air support, but this part of the argument is hard to dismiss. A weapon that seems awkward in a stealth discussion can make sense when the mission shifts from deep penetration to supporting people on the ground.

The “Flaw” That Created A Modular Slot

The host also pointed out a paradox: the external gun can be more stable than the internal gun in the F-35A.

According to Navy Decoded, the F-35A’s internal gun has faced accuracy and structural concerns over the years, including problems tied to alignment and recoil effects on parts of the aircraft structure. The host said the external pod avoids those issues because the recoil is isolated through the centerline hardpoint instead of being driven into the aircraft skin and internal structure.

That does not mean the pod is free of cost. It adds drag and affects the aircraft’s transonic acceleration, with the F-35C taking the largest penalty because of its size, fuel load, and wing design.

But the pod’s drawback also created something useful: a removable centerline mission space.

Navy Decoded said the same outer shape used for the gun pod can support other payload concepts, including electronic warfare equipment, intelligence and surveillance sensors, drone-control links, or even future directed-energy systems. Because the pod shape has already gone through aerodynamic and radar-cross-section testing, the shell itself becomes a certified platform that can be filled with different mission packages.

That is where the design begins to look less like a flaw and more like a slot reserved for future missions.

The F-35A’s internal gun is fixed inside the aircraft. The F-35B and F-35C can carry a gun, leave the station empty, or potentially use the same space for something else.

That kind of adaptability matters for an aircraft expected to serve for decades. The threat environment will change, weapons will change, drone teaming may become more important, and electronic warfare will likely keep expanding. A removable pod gives planners a way to update the aircraft without rebuilding the airframe.

A Compromise That May Age Better Than Expected

Navy Decoded’s central point was not that an external gun pod is stealthier or cleaner than an internal gun. It plainly is not.

The point is that the F-35B and F-35C were forced into an external solution because there was no room inside, and that compromise may have given them more flexibility than the elegant internal solution on the F-35A.

When stealth is essential, the pod can stay off. When Marines need ship-based close fire support, the gun can go on. When future missions demand a jammer, sensor package, or drone-control node, the same physical space may become something entirely different.

That is a more nuanced story than the simple headline that America’s most expensive stealth fighter carries a radar-visible gun.

The pod is not a perfect answer. It adds drag, it affects stealth when mounted, and it carries only 220 rounds. But it also gives the Marines a weapon they may need in the kind of fight they are built for, and it gives the aircraft a modular centerline option that may become more valuable as the F-35 ages.

As the Navy Decoded host put it, the F-35A locked in an internal answer, while the F-35B and F-35C were forced to leave a question open before every mission: what does this sortie actually need?

For a fighter expected to remain relevant for half a century, that open slot may prove to be more important than the gun that first filled it.