No person, except a police officer in the performance of duty, shall, within the city, discharge any gun, pistol, or firearm of any description or carry any such weapon, unless it is dismantled or broken apart, or carried in a case in such a manner that it cannot be discharged. This section does not prevent the carrying of a hand gun within the city under a permit subject to the restrictions imposed by law or exception of use at ranges licensed under § 132.04 of this chapter.