1. Short title This Act may be cited as the Stop Harassing Owners of Rifles Today Act or as the SHORT Act . 2. Definition of firearm (a) In general Subsection (a) of section 5845 of the Internal Revenue Code of 1986 is amended to read as follows: (a) Firearm (1) In general The term firearm means— (A) a machinegun, (B) any silencer (as defined in section 921 of title 18, United States Code), and (C) a destructive device. (2) Exception The term firearm shall not include an antique firearm or any device (other than a machinegun or destructive device) which, although designed as a weapon, the Secretary finds by reason of the date of its manufacture, value, design, and other characteristics is primarily a collector's item and is not likely to be used as a weapon. . (b) Shotguns not treated as destructive devices Section 5845(f) of the Internal Revenue Code of 1986 is amended by striking except a shotgun or shotgun shell which the Secretary finds is generally recognized as particularly suitable for sporting purposes and inserting except shotgun shells and any weapon that is designed to shoot shotgun shells . (c) Conforming amendments Section 5811(a) of the Internal Revenue Code of 1986 is amended by striking , except, the transfer tax on any firearm classified as any other weapon under section 5845(e) shall be at the rate of $5 for each such firearm transferred . (d) Effective date The amendment made by this section shall apply to calendar quarters beginning after the 90-day period that starts on the date of the enactment of this Act. 3. Elimination of disparate treatment of short-barreled rifles and short-barreled shotguns used for lawful purposes Section 922 of title 18, United States Code, is amended— (1) in subsection (a)(4)— (A) by striking , machinegun and inserting or machinegun ; and (B) by striking short-barreled shotgun, or short-barreled rifle, ; and (2) in subsection (b)(4)— (A) by striking , machinegun and inserting or machinegun