US Navy Could Add “Hypervelocity Projectile” to Deck-Mounted 5-inch Guns

By Kris Osborn, President, Center for Military Modernization

As Houthi-drone and small boat attacks intensify in the Red Sea, US Navy attention has been further directed toward its series of ongoing upgrades to layered ship defenses, a long-standing campaign to better arm surface ships against a new generation of potential enemy threats.

A critical part of this has involved multi-year efforts to increase the range, precision and lethality of the US Navy’s famous 5-inch guns. Since the WWII era, these Mk45 deck-mounted guns have delivered suppressive fire, attack land targets, fortified amphibious assaults with supportive fires and fired on enemy ships. In more recent years, the changing threat equation has inspired the Navy to pursue a number of efforts to improve range, precision and lethality for the Mk 45.

BAE Systems has been working with the Navy the mature Mk45 technology, some of which goes back to previous service efforts on a “rail gun,” however the firm has ventured beyond these previous efforts to migrate the HVP from its previous applications to deck-mounted Navy Mk45 5-inch guns. The early days of the HVP started back in 2013 in collaboration between BAE Systems and the Naval Surface Warfare Center Dahlgren for the Railgun Program.

Integrating the HVP into 5-Inch guns adds precision, range and maneuverability; as is often the case with industry research & development, major industry partners often invest internal funds to develop and prepare technologies well suited to meet Navy needs, solve a problem or “close” a capability gap.

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“We’ve been modernizing the Mk45 for many years, and the most recent development is the application of the Hyper-velocity projectile (HVP). We want to answer Navy’s challenges in what is a trifecta. …increased lethality, increased capacity of that lethal capability and affordability,” Tate Westrook, Director of Business Development for BAE Systems, Navy Guns & Surface Ship Missiles, told Warrior at the 2024 Surface Navy Association Symposium.