(L) "Dangerous ordnance" does not include any of the following:
(1) Any firearm, including a military weapon and the ammunition for that weapon, and regardless of its actual age, that employs a percussion cap or other obsolete ignition system, or that is designed and safe for use only with black powder;
(2) Any pistol, rifle, or shotgun, designed or suitable for sporting purposes, including a military weapon as issued or as modified, and the ammunition for that weapon, unless the firearm is an automatic or sawed-off firearm;
(3) Any cannon or other artillery piece that, regardless of its actual age, is of a type in accepted use prior to 1887, has no mechanical, hydraulic, pneumatic, or other system for absorbing recoil and returning the tube into battery without displacing the carriage, and is designed and safe for use only with black powder;
(4) Black powder, priming quills, and percussion caps possessed and lawfully used to fire a cannon of a type defined in division (L)(3) of this section during displays, celebrations, organized matches or shoots, and target practice, and smokeless and black powder, primers, and percussion caps possessed and lawfully used as a propellant or ignition device in small-arms or small-arms ammunition;
(5) Dangerous ordnance that is inoperable or inert and cannot readily be rendered operable or activated, and that is kept as a trophy, souvenir, curio, or museum piece.
(6) Any device that is expressly excepted from the definition of a destructive device pursuant to the "Gun Control Act of 1968," 82 Stat. 1213, 18 U.S.C. 921(a)(4), as amended, and regulations issued under that act.