he US Navy recently released footage of its first testfire of an electromagnetic railgun at their new terminal at Office of Naval Research and Naval Surface Warfare Center. Railguns use 20 to 32 mega joules of electromagnetic energy to fire projectiles at seven to nine times the speed of sound, according to a Congressional Research Service report on the weapons. Because they fire with electricity alone — not chemical explosives like conventional ammunition — railguns can potentially operate much cheaper and fire much much faster than weapons currently used by the Navy. The Navy has long sought the technology as...