A system using Faraday's law to rapidly convert the kinetic energy of a magnetized and/or conducting projectile (112) into usable electrical energy includes a barrel (102) comprising a bore (104), a circuit including a coil (144) distributed along a length of the bore and means (154, 156) to store electrical energy, and a projectile (112) comprising at least one of a conductive material or a magnetic material magnetically coupled to the coil when the projectile is moving along the length of the bore. The circuit stores energy generated from an electric current induced in the coil when the projectile moving along the length of the bore causes a magnetic interaction between the coil and the magnetic material or the conductive material. The magnetic interaction also causes braking of the projectile. The system may be removably attached to a firearm (130).