Railgun

A railgun is a type of artillery that fire projectiles at supersonic speeds by launching them out of using electromagnetism instead of gun powder. Current expectations for railguns are a 400 mile (643.6 kilometer) range and an impact velocity in excess of Mach 8. Current problems with railguns are power generation and barrel life. Railguns require large amounts of power to work in the first place. They also go through barrels quickly because of the extreme temperatures inside the barrel. Railguns currently only exist as prototypes and in science fiction.