It shall be unlawful for any person to fire or discharge any firearm, air gun, slingshot, bow, crossbow, or other device designed to fire, project, or throw any stone, bullet, or other hard substance within the village; provided, however, that this section shall not apply to any police officer discharging a firearm in the performance of his duty, nor any citizen from discharging any firearm when lawfully defending his person or property. (1974 Code)