CORRECTION: This post has been updated to include a new statement from Naval Sea Systems Command that changes one previously given to USNI News revising the planned speed of hyper velocity projectile fired from a Mk 45 naval gun from Mach 5 to Mach 3. The U.S. Navy’s deck guns could take on new relevance if ongoing tests to fire a guided round at three times the speed of sound from their muzzles are successful, USNI News has learned. Using rounds initially designed for the service’s emerging electromagnetic railgun, Naval Sea Systems Command are now in early testing phases of...