How the railgun sounds

Rico's friend Kelley, also a military hardware freak, forwards this splendid video (turn up the volume), and Sam Biddle has an article at Gizmodo.com:

It fires a forty-pound metal slug up to 5,600 miles per hour from New York City to Philadelphia, slamming into its target with 32 times the force of a "one-ton car moving at a hundred mph". Railguns aren't sci-fi anymore.
We'd seen experimental lab models of a railgun weapon that were impressive enough, but they were just that: lab models. Enormous, room-filling contraptions that looked nothing like something you'd see on the deck of a destroyer. But for the first time, the Navy says it's successfully tested a fully weaponized railgun built by BAE, a private weapons firm. This is a huge milestone, bending the thing away from paper and fiction. "It finally looks like a gun," the Navy told us. And they're right. Each round is designed to destroy ships, land targets, and missiles (ha!) with nothing more than kinetic energy— the equivalent of throwing a rock through someone's window. Right now the Navy's employing deliberately non-aerodynamic rounds that slow down (so the Virginian testing ground doesn't level a town), but they'll be refined into GPS-guided piercing conical chunks down the line. But that line is long.
The plan is to continue testing over the next five years, ramping up the energy level to 32 megajoules and beyond. How to power such an extraordinary gun is another question entirely, however. The Navy is hoping for an ambitious rate of ten rounds per minute, but at the moment, there's nothing in our fleet that could deliver that kind of juice. Batteries "similar to those used in hybrid cars" seem to be the best option, but batteries run out. And you don't want to run out of batteries in the middle of a naval battle. The Navy also doesn't seem to have a clue how it'll use the railgun as an anti-missile system, one of its stated plans.
Between budget cuts and engineering hoops, the day a railgun sees real action on the seas is probably very far away and, besides, we don't have any enemies to use it against beyond spooky Cold War ghosts. But the the destructive spectacle the railgun represents, and the tremendous leap beyond the kind of guns we've been using for almost a century now, is profound.

Rico says the military has always wanted the latest toys, and will find a use for them eventually...