Navy Tests Incredible Sci-Fi Weapon. By LiveScience Staff. 01 February 2008 12:25 pm ET

The U.S. Navy yesterday test fired an incredibly powerful new big gun designed to replace conventional weaponry aboard ships.

The big gun uses electromagnetic energy instead of explosive chemical electromagnetic energy propellants to fire a projectile farther and faster. The railgun, as it is called, will ultimately fire a projectile more than 230 miles (370 kilometers) with a muzzle velocity seven times the speed of sound (Mach 7) and a velocity of Mach 5 at impact.

The test-firing, captured on video, took place Jan. 31 in Dahlgren, Va., and Navy officials called it the "world's most powerful electromagnetic railgun."

The Navy's current MK 45 five-inch gun, by contrast, has a range of less than 23 miles (37 kilometers).

The railgun's high-velocity projectile will destroy targets with sheer kinetic energy rather than with conventional explosives.

The Navy's goal is to demonstrate a full-capability prototype by 2018.