The present invention provides an ammunition disabling system for selectively disabling ammunition that is operatively coupled to a selectively changeable material. In the operative state the material permits transmission of a percussive impact through the material for enabling firing of the ammunition; and in the deactivated state the material inhibits transmission of the percussion wave through the material for preventing firing of the ammunition. The ammunition disabling system includes an energy wave generator with an energy wave source that emits an energy wave at a frequency resonant a natural frequency of the material. When the ammunition with the material are exposed to the energy wave, the energy wave induces a response (physical and/or chemical) in the material that results in a mechanical change in the material from the operative state to the deactivated state by degrading the mechanical structure of the material.