Reply to ``Electrodynamic force law controversy''

Our paper [Phys. Rev. E 58, 2505 (1998)] confirmed the validity of both Ampère and Grassmann's force law even for the action exerted on a part of a current loop. Since that part can be an element of a circuit, both force laws also predict the same internal stresses and the same recoil for a railgun. Graneau and Graneau [preceding paper, Phys. Rev. E 63, 058601 (2001)] neglected the action on the breech of the railgun, an action that produces the same recoil for both force laws. The reaction to the force exerted on the armature does not act on the rails but on the breech that, simply because of symmetry, undergoes a force equal and opposite to the one acting on the armature.