The US Navy’s trademark MK 38 close-in weapon system is being reborn for a fourth time, receiving its first-ever caliber increase in over three decades.
The MK 38 MOD 4 now replaces the previous 25mm gun with a Bushmaster II 30mm main gun from Northrop Grumman, adding air-burst munitions to the shipboard shooter.
Electro-optical/infrared (EO/IR) sights and operator console also upgrade the weapon’s targeting, transforming it into a “smarter” weapon that can keep up with modern threats.
To add to its firepower, a 12.7mm heavy machine gun fitted with a special sensor can be deployed by troops, boosting responsiveness against maritime and airborne threats.
Led by the Naval Surface Warfare Center Dahlgren Division (NSWCDD), the upgrade also integrates the gun with the Aegis Combat System for faster target tracking, improved threat coordination, and seamless operation with other shipboard sensors.
“It is going to greatly improve the ship’s ability to counter modern threats,” said technical program lead Danny Mudd. “With the added caliber, we can reach farther and deliver more damage.”
MK 38 Evolution
The MK 38 debuted in the Persian Gulf during the 1990s.
Its MOD 2 upgrade turned it into a remotely controlled weapon that can maintain stability even on rolling decks.
The MOD 3, fielded in 2017, added an optional 7.62mm gun and EO/IR sensors for a 330-degree view.
Now, the MOD 4 is positioned to counter small, agile maritime threats and has already been installed on the Arleigh Burke-class USS Mustin. NSWCDD is finalizing compatibility across additional platforms.
“We’re tracking the emergence of new threats, now including airborne ones, and adapting accordingly,” Mudd stressed. “The MOD 4 is designed to deliver greater lethality across a wider range of targets, strengthening overall ship defense and giving us the edge we need.”
