A railgun is a gun that fires a projectile (bullets or plasma) using a magnetic field produced by electricity. Unlike regular guns, it does not use gunpowder or other explosive propellants, and rarely needs to be cleaned or unjammed. Currently, most railguns are experimental and are not used in actual combat, but the United States Navy is expecting to have one operating soon. In theory, a railgun could fire a bowling-ball-sized projectile fast enough to destroy a small building, even over long distances. An ordinary gun can fire its projectile as fast as 2 km/s but a railgun might reach 3 km/s. Railguns are usually very large and not portable because of the need for a large power supply. There have been proposals to use ths technology for non-weapon purposes, such as aircraft and space launch vehicles and specialized tools.

The driving force of a railgun power is the magnetic field created when electricity runs through the rails from the positive to negative ends. The more electricity running through the rail, the stronger the magnetic field. The railgun projectile is positively charged so it is repulsed by the positive end. In most railguns millions of amperes are ran through the positive end to the negative end. When the positive charge run through the railgun nears and leaves the projectile lorentz force acts on the projectile. This propels it out of the rail gun.