(a) The county board of any county may, by ordinance, regulate or prohibit within unincorporated areas the discharge of firearms in any residential area where such discharge is likely to subject residents or passersby to the risk of injury. However, such an ordinance shall not limit the right to discharge a firearm for the lawful defense of persons or property, or in the course of making a lawful arrest, when such use of force is justified under Article 7 of the Criminal Code of 2012.
     (b) For the purposes of this Section, a “residential area” is any area within 300 yards of at least 3 single or multi-family residential structures.