The Rigsby Coil Gun,
Invented by a Texas man named Virgil Rigsby in 1934, the Rigsby Coil Gun was a machine that was unique in that it used electromagnets as its source of ignition. A coil gun, also known as a Gauss gun, does not use an expanding gas propellant such as gunpowder. Rather the projectile is propelled down the barrel using a series of electromagnets which, if timed right, will pull the projectile down through the barrel and out of the bore at high velocity..
The Rigsby Coil Gun fired at a rate of 150 rounds per minute with little sound or recoil. It was featured in a 1936 edition of Popular Mechanics but other than that saw little use of exposure. The military was uninterested in the design because it was large, delicate, and required massive amounts of power to operate.