A railgun is a device that uses electromagnetic force to launch high velocity projectiles, by means of a sliding armature that is accelerated along a pair of conductive rails. It is typically constructed as a weapon and the projectile normally does not contain explosives, relying on the projectile's high speed to inflict damage. The railgun uses a pair of parallel conductors, or rails, along which a sliding armature is accelerated by the electromagnetic effects of a current that flows down one rail, into the armature and then back along the other rail. It is based on principles similar to those of the homopolar motor.
Railguns are being researched as weapons that would use neither explosives nor propellant, but rather rely on electromagnetic forces to impart a very high kinetic energy to a projectile (e.g. APFSDS). While explosive-powered military guns cannot readily achieve a muzzle velocity of more than about 2 km/s, railguns can readily exceed 3 km/s, and perhaps exceed conventionally delivered ammunition in range and destructive force. The absence of explosive propellants or warheads to store and handle, as well as the low cost of projectiles compared to conventional weaponry come as additional advantages.
After the attack on The Flame Dragon on Koda villagers, Itami complained that the JSDF should have given railgun to deal with the Flame Dragon effectively in order to minimize casualties from the villagers. According to one of the JSDF official, the railgun is still under development by the US military and states the Flame Dragon won't stand a chance against a well-shot railgun since its can punch through its tough skin like tissue paper.