I've heard about the concept on sci-fi shows, but didn't realise until I read this article that anyone was actually working to produce such a thing.The Naval Surface Warfare Center in the US has a working model of a rail gun that fires a 3.2kg projectile a distance of 200 nautical miles in 6 minutes, using an electromagnetic device.
The power of the impact is equivalent to "hitting a target with a Ford Taurus at 380 mph".
