US Navy Test-fires Missile-Killing Hyper Velocity Projectiles from Deck Gun

A US Navy warship has fired 20 hyper velocity projectiles (HVP) from a standard Mk 45 5-inch deck gun for effective defence against cruise missiles and unmanned air vehicles (UAV).

Though standard fixtures on most US Navy warships, the Mk 45 5-inch deck gun is based on World War II concept of defending warships against decades-old threats. However, in the changing warfare scenario of cruise missiles and armed UAVs, the need for a deck gun was increasingly being questioned.

USNI news reported that The test-firing, conducted on USS Dewey (DDG-105) by the Navy and the Pentagon’s Strategic Capabilities Office as part of the Rim of the Pacific (RIMPAC) 2018 international exercise, was part of a series of studies to prove that HVPs could be fired from the deck guns which are based on  more than 40-year-old design.

It was not revealed if the test firing involved targets or merely intended to assess projectile speed.

The HVPs can convert the Mk 45 5-inch deck gun into an effective and low-cost weapon against cruise missiles and larger UAVs.

While the HVP was originally designed to be the projectile for the electromagnetic railgun, the Navy and the Pentagon see the potential for a new missile defense weapon that can launch a guided round at near-hypersonic speeds.

Currently, the fleet uses a combination of missiles – like the Evolved Seasparrow Missile, the Rolling Airframe Missile and the Standard Missile 2 – to ward off cruise missile threats. The missiles are effective but also expensive, Bryan Clark with the Center for Strategic and Budgetary Assessments was quoted as saying by USNI News on Monday.

“So if you think about the kinds of threats you might face in the Middle East, the lower-end cruise missiles or a larger UAV, now you have a way to shoot them down that doesn’t require you use a $2 million ESSM or $1 million RAM because a hyper velocity projectile – even in the highest-end estimates have it in the $75,000 to $100,000 range, and that’s for the fanciest version of it with an onboard seeker,” he said.

An added benefit of using HVP in powder guns is the gun’s high rate of fire and a large magazine capacity.

“You can get 15 rounds a minute for an air defense mission as well as a surface-to-surface mission,” Clark said. “That adds significant missile defense capacity when you think that each of those might be replacing a ESSM or a RAM missile. They’re a lot less expensive.”

In 2016, guided-missile destroyer USS Mason (DDG-87) fired three missiles to ward off two suspected Iranian cruise missiles fired from Houthi rebels in the Red Sea, in what amounted to a multi-million dollar engagement.