The red and yellow warning flags were out. The gun range was cleared. The klaxon sounded.

"System is enabled," the voice on the speakerphone said. There was a pause, then a distant thud that could be felt through the floor.

"Gun is fired," the voice said.

Inside a cavernous building at the Naval Surface Warfare Center in Dahlgren, Va., on Friday, a gigantic pulse of electricity hurled a 20-pound slug of aluminum out the barrel of an experimental gun at seven times the speed of sound.

The slug trailed a pillar of fire as it left the weapon and the building, illuminating the surrounding woods like a giant flashbulb. It streaked down range, generating a small sonic boom, and traveled about 5,500 feet before tumbling to the ground harmlessly.

In an adjacent building, there was a round of applause from observing scientists.

It was the latest test of the Navy's electromagnetic railgun - a futuristic weapon that is right out of the latest video war game and could one day change the face of Naval warfare.

Roger Ellis, the railgun program manager, said people "see these things in the video games, but this is real. This is what is very historical."

The gun is fired with a huge jolt of electricity that can propel a round more than 100 miles and at such velocity that it does not need an explosive warhead.

Two tests were conducted Friday - the first of which the Navy said generated a world record 33 megajoules of force out of the barrel. The second shot, witnessed by reporters, produced 32 megajoules.

Forty-five minutes after the second shot, a part of the battered bullet that was retrieved from the range was still warm to the touch.

The Navy hopes the railgun might bring a sci-fi level of range and firepower to its fleets of the future.