Except as otherwise provided in section 3-7-5 of this chapter it shall be unlawful in said city, for any person under the age of eighteen (18) years to fire, discharge, shoot or operate, or to assist or participate in the firing, discharging, shooting, or operating, or to have in his or her possession, care, custody or control, any gun, revolver, pistol, firearm, spring gun, air gun, sling, slingshot, or device designed, or intended to discharge, or capable of discharging, any dangerous missile, or any cartridge, shell, ammunition or device containing any exploding substance, designed or intended to be used in or fired from any gun, revolver, pistol or firearm. (1960 Code)