U.S. Navy Deploys Mk 38 Mod 4 Guns to Shield Warships From Drone Swarms
Asymmetric drone warfare across modern maritime choke points has fundamentally altered how surface combatants defend themselves against saturation attacks. Hostile regional forces and non-state actors operating in high-threat waterways have increasingly challenged naval defenses with low-cost uncrewed aerial vehicles and explosive uncrewed surface vessels. To protect multi-billion-dollar surface fleets without draining critical interceptor inventories, naval commanders are prioritizing rapid upgrades to shipboard point-defense hardware, placing modern close-in systems like the ‘Mk 38 Mod 4’ at the core of their tactical survival doctrine.
For decades, American warships relied on layered outer shields composed of long-range surface-to-air missiles alongside legacy close-in guns to neutralize approaching threats. However, recent combat operations in congested maritime corridors exposed a severe cost and volume disparity when firing million-dollar interceptors at expendable adversary drones. Expanding gun-based defenses with stabilized mounts, greater range, and specialized munitions has become essential to preserve missile magazines for high-end threats like anti-ship cruise and ballistic missiles.
To address this tactical gap, the U.S. Navy is expanding its deployment of the advanced ‘Mk 38 Mod 4’ Gun Weapon System across the surface fleet. The service awarded a three-year contract valued at up to $197 million to manufacturer MSI-Defence Systems to procure stabilized gun mounts and electro-optical sights. The initial phase commits $61.3 million to deliver 22 gun mounts and 23 precision sensor systems, building on operational sea trials conducted by the guided-missile destroyer USS ‘Mustin’.
The ‘Mk 38 Mod 4’ introduces a radically different design compared to legacy 25mm variants, replacing the older weapon with an externally powered 30mm Northrop Grumman ‘Mk 44 Bushmaster II’ chain gun. In a unique piggy-backed configuration detailed by The War Zone, engineers mounted a .50 caliber ‘M2’ heavy machine gun directly atop the primary autocannon. This dual-caliber setup enables the mount to unleash rapid suppressive fire against fast inshore attack craft while retaining heavier kinetic punch against resilient aerial drones.
Targeting and tracking capabilities also receive a major technical leap through the separate, off-mount ‘Mk 48 Mod 2’ Electro-Optical Sight System. By decoupling the camera and laser rangefinder assembly from the gun mount itself, the system maintains stable target tracks through heavy seas and poor visibility while the ship pitches and rolls. Furthermore, technical teams linked the mount directly into the shipboard ‘Aegis’ Combat System, allowing operators to acquire targets via naval radar and fire programmable air-burst munitions with automated precision.
Deliveries under the multi-year manufacturing effort are slated to run through January 2031, with hardware targeted for ‘Arleigh Burke’-class destroyers and future polar security cutters, as reported by Defence Blog. The new mounts will operate alongside the 20mm ‘Phalanx’ Close-In Weapon System and the 5-inch 62-caliber ‘Mk 45’ deck gun, creating a dense inner ring of defensive fire. By housing 400 rounds in dual-feed ammunition bins and enabling remote firing from combat direction centers, the system keeps personnel off open decks during intense engagements.
As uncrewed surface and aerial threats continue to proliferate across critical global sea lanes, naval warfare is increasingly governed by magazine depth and economic efficiency. The widespread fielding of the dual-gun ‘Mk 38 Mod 4’ ensures American warships maintain a lethal, sustainable shield against swarms without sacrificing their premier guided interceptors. Through this integration of automated fire control and heavy caliber firepower, the fleet hardens its defenses against the relentless evolution of autonomous combat.
