Mach 7 for Naval Gun

SeaPower magazine is reporting this, but the Navy is getting hush-hush:

The rail gun, which fires projectiles by drawing them through the barrel by a massive current of electromagnetic energy, offers advantages that are revolutionary in naval gunnery. Ranges never before dreamed of for naval artillery — 200 to perhaps 300 nautical miles — would be possible, enabling sustained strikes far inland in any weather.
With no need for explosive propellant charges, ship and crew safety is considerably enhanced. Catastrophic magazine explosions would no longer be possible, for example. Logistics would be simplified without the need to handle propellant charges and more rounds could be stored in a magazine.
The rail gun concept is not new and, until recently, was discussed openly by the Navy. The service, however, has tightened discussion of the subject.