U.S. Navy’s Mk 45 Guns Are Coming Back Stronger, BAE Systems Gets Major Rebuild Contract

Military Sentinel, Washington — The U.S. Navy has expanded a contract with BAE Systems by $38.2 million to overhaul two Mk 45 Mod 4 deck guns, the primary gun mounted on the service’s Arleigh Burke-class destroyers and Ticonderoga-class cruisers, with the rebuilt weapons due back to the fleet by March 2030.

Contract Details

Naval Sea Systems Command issued the award as a cost-plus-incentive-fee modification to an existing BAE Systems contract, according to Defence Blog’s reporting. The funding draws on fiscal year 2024 shipbuilding money that remains available past the current fiscal year a routine mechanism for multi-year ship-system overhaul work. The refurbishment work itself is slated for BAE Systems’ facility in Louisville, Kentucky.

What the Mk 45 Mod 4 Brings to the Fleet

The Mk 45 is a 127 mm (5-inch), 62-caliber naval gun that BAE Systems markets as the lightest, most compact, and most widely fielded 5-inch gun system in service today, with more than 260 units delivered across the U.S. Navy and ten allied navies — including Australia, South Korea, Japan, and Denmark.

Aboard U.S. warships, the gun handles a mix of missions: naval surface fire support, anti-surface engagements, and a limited air-defense role.

The Mod 4 variant specifically being overhauled under this contract adds:

• A structurally reinforced mount that increases firing energy by roughly 50%, extending both the speed and range of fired rounds
• A fully digital fire-control system with a touch-screen operator interface
• A lower-maintenance, reduced-signature gun shield

Paired with the Navy’s 5-inch Cargo projectile and an improved propelling charge, the Mod 4 configuration reportedly extends engagement range past 20 nautical miles (about 37 km).

Strategic Context

This isn’t BAE Systems’ first recent Mk 45 windfall. In January 2025, the company secured a $70 million contract that built on a prior $47 million order for similar overhaul work. At the time, a BAE Systems executive pointed to Houthi attacks on U.S. Navy vessels in the Red Sea as evidence that deck-gun firepower remains relevant for close-in self-defense at sea a reminder that even legacy gun systems retain a role alongside missile-based defenses.

Outlook

The steady cadence of Mk 45 overhaul contracts — two sizable awards inside roughly 18 months suggests the Navy is treating deck-gun readiness as an ongoing sustainment priority rather than a one-off fix, likely tied to surface combatant deployment tempo in contested waters such as the Red Sea and broader Indo-Pacific tasking. Whether this signals a broader refresh across the Arleigh Burke and Ticonderoga fleets, or simply reflects routine depot-level maintenance rotation, is not established by the available reporting and would require NAVSEA’s fleet maintenance schedule to confirm.