I’ve always loved the name ‘rail gun’ – of all the various futuristic weapons concepts I’ve encountered, it’s probably the most down to earth name. And, since it’s based on an idea you can replicate at home with a bunch of wire and a battery, it’s always seemed one of the most practical.
The US Navy’s been interested in rail guns for use on their various capital ships – they’re aiming for a 64 MJ version that will be able to lob projectiles up to 200 miles.
A recent article in the MIT Technology Review describes a 10 MJ gun which is nonetheless scarily impressive. Particularly because, at over 2 kilometres a second, a 3 kg slug is travelling fast enough to cause flakes of aluminium on it to spontaneously combust, leaving an impressive fiery tail.