The Navy has spent seven years testing out the components of a way-futuristic weapon: a shipboard cannon that blasts bullets over vast distances at hypersonic speeds using bursts of electricity. But so far, that weapon, known as the Electromagnetic Railgun, has been more of a lab experiment than an honest-to-God weapon. It didn't even have basic gun-like features, like a barrel. Now, however, the Navy is unveiling the first actual railgun guns, which it'll test for another five years, in the hope of winning over legislators who consider it a waste of time, money and electricity.

Previous versions of the railgun have been laboratory test models, stored in a hangar at Dahlgren Naval Surface Warfare Center in Virginia. They look like shipping containers or school buses put up on blocks, hooked up like Frankenstein's monster to giant generators that pump dozens of megajoules of energy necessary to fire the bullet. All that has cost nearly a quarter of a billion dollars. And you couldn't fit any of it onto a ship, and it wouldn't actually be a real weapon if you did.

At least not until Jan. 30, when BAE Systems sent its first actual gun-shaped railgun to Dahlgren. Competitor General Atomics will send its own design there in April. Both designs have 12-meter barrels. "Now that looks like a real gun," said Roger Ellis, the railgun chief for the Office of Naval Research, which has inaugurated the next phase of tests to determine the gun's practicality – something many in Congress doubt.

The Navy released video of the first tests, viewable above, on Tuesday. The dramatic mini-inferno in the wake of the slug fired from the railgun is the result of "1 million amps flowing through" the gun, said test chief Tom Boucher, the hypersonic speed of the shot, and the actual aluminum of the bullet – "reactive in the atmosphere" – burning off.

It's the next step in a process – an expensive one – the Navy hopes will lead to a whole new era of self defense for ships, and way, way long-range strikes from on deck by the early 2020s. The Navy's current 5-inch deck guns top out at 13 kilometer ranges. By 2017, the Navy wants the railgun prototypes to fire several shots per minute without soaking up a ship's juice.

The idea behind the Electromagnetic Railgun is to fire a bullet at hypersonic speeds using dozens of megajoules of electricity. The Navy wants it to guard the surface ships of the 2020s, unsubtly boasting to adversaries that messing with the ships will lead to bullets shooting across hundreds of miles of ocean in mere minutes. The Office of Naval Research says it will give sailors "a dramatically increased multimission capability," like fire support for land strikes over long, long distances beyond the reach of enemy defenses, and defense against "cruise and ballistic missiles" that target ships. No wonder the railgun's official motto is "Velocitas Eradico" – "Speed Kills."

Lab tests have pleased the Navy, if not Congress. In December 2010, the Office of Naval Research fired a shot with 33 megajoules of energy, a world record, sending a 23-pound bullet 5500 feet in a single second. The Senate Armed Services Committee still found the science too impractical, and recommended killing the railgun, until a Navy congressional counterstrike revived the program.

Now that the Navy has an actual prototype railgun to shoot, the plan is to hook it up to sensors and cameras to test its performance at 20 and 33 megajoules' worth of energy. Its goal is produce accurate shots from 50 to 100 nautical mile distances, which the Navy wants by 2017.

Even railgun advocates concede there are a host of other challenges the hypersonic weapon will have to overcome. Its barrel will have to withstand repeated fires without wearing out. (The Navy wants to up firing rates to 10 per minute.) It's got to fire smart bullets without frying the guidance systems during a blast. (The Navy says both BAE and General Dynamics are starting to design "a next-generation thermally managed launcher.") And it's got to be affordable. (The Navy has spent $240 million on the railgun so far, and it expects to spend about as much through 2017 on tests – before buying a single one of the things.)

Another big problem: the current generation of Destroyers can't produce the power to fire the railgun without diverting juice from the propulsion systems. One of the goals of the railguns over the next five years is to create workarounds, so the guns will be relevant to their intended ships. Those include "an intermediate energy store using energy-dense batteries, similar to [those on] hybrid cars," Ellis told reporters on a Tuesday conference call. "That enables us to put the railgun on ships that don't have larger power supplies."

Which should underscore how the Navy really, really loves its railgun – enough to go to the mat with Congress about it and win. That's not going to relent now that it actually has a real cannon to shoot.