The Navy test-fired a series of new hypervelocity projectiles this past summer from the destroyer USS Dewey during Rim of the Pacific exercises off Hawaii that the Congressional Research Service said could be a “game changer” for defending warships against an increasingly sophisticated array of Chinese missiles.

Twenty of the fast-flying projectiles were fired from the San Diego-based ship’s 5-inch main deck gun, U.S. Naval Institute News reported. The Navy confirmed the test.

While the Navy is developing an electromagnetic railgun that can hurl projectiles at speeds of 4,500 to 5,600 mph, or roughly Mach 5.9 to 7.4, the Hawaii tests used the Mk 45 5-inch gun found on cruisers and destroyers.

Microspoilers and GPS input guide the projectile to its target.

The Congressional Research Service said in a late October report that the Navy’s surface laser weapon system, electromagnetic railgun and the hypervelocity projectile, re-branded as the “gun-launched guided projectile,” are expected to improve the ability of Navy surface ships to protect themselves against missiles and unmanned aerial vehicles.

“Any one of these three new weapons, if successfully developed and deployed, might be regarded as a ‘game changer’ for defending Navy surface ships,” the research serv­ice said. “If two or three of them are successfully developed and deployed, the result might be considered not just a game changer, but a revolution.”

Two key limitations in that defense are the ability to carry munitions and their cost. Concern has been raised over the survivability of Navy ships in the face of advanced missiles from nations such as China to the point that U.S. ships in coming years might have to avoid operating in waters within range of such missiles.

Defensive missiles cost $800,000 to a few million dollars apiece, and would have to be used in great number to counter incoming salvos of enemy missiles.

The much smaller gun-fired guided projectiles, meanwhile, have a unit procurement cost of about $85,000, according to the research service.

Even though the new projectiles, fired from 5-inch traditional gunpowder guns, might not be able to counter high-arcing anti-ship ballistic missiles, they could help defend against low-flying anti-ship cruise missiles, leaving Navy ship defensive missiles for other threats.

BAE Systems, which is developing the hypervelocity projectile, said it can be used by Navy, Marine Corps and Army guns.

The projectile’s low-drag aerodynamic design “enables high velocity, maneuverability, and decreased time to target,” BAE said on its website. “These attributes, coupled with accurate guidance electronics, provide low-cost mission effectiveness against current threats and the ability to adapt to air and surface threats of the future.”