It is unlawful for any person to discharge any firearm or gun or rifle or other gun or device discharging by the use of powder, air or springs any bullet, shot or other object, or any sling or slingshot in the city, except in duly licensed shooting galleries and/or on pistol and rifle ranges approved by the chief of police. The provisions of this section shall not apply to peace officers acting within the scope of their official duties. [1937 Code § 550.]