Rifle. A weapon designed or redesigned, made or remade, and intended to be fired from the shoulder. Also, designed or redesigned and made or remade to use the energy of the explosive in a fixed cartridge to fire only a single projectile through a rifled bore for each single pull of the trigger, and shall include any such weapon which may be readily restored to fire a fixed cartridge.
32 CFR § 552.126
For the purpose of this part, the following definitions apply: