An electromagnetic launcher having spaced-apart rails for launching a projectile by means of a current-carrying armature between the rails includes a breech end loop connected to a current commutating firing switch. A low resistance shorted loop is positioned in proximity to the breech loop and generates a current in a direction counter to the commutated breech current. The arrangement reduces the equivalent breech inductance which in turn reduces communication arcing energy as well as the duration of arcing, thereby prolonging firing switch life.