Removes the shotgun-related clauses from the definition of "firearm" in subsection (a) and renumbers/redesignates the remaining paragraphs.

Replaces the existing exclusion for certain shotguns/shotgun shells that the Secretary finds suitable for sporting purposes with a different exclusion that excepts shotgun shells and any weapon designed to shoot shotgun shells.

Amends 18 U.S.C. 922 by striking language in subsections (a)(4) and (b)(4).

Adds a provision preempting State or political subdivision laws that (1) impose a tax (other than a generally applicable sales or use tax) on making, transferring, using, possessing, or transporting a short-barreled shotgun in or affecting interstate or foreign commerce, or (2) impose marking, recordkeeping, or registration requirements with respect to such a shotgun, by declaring such laws shall have no force or effect.

Adds a new subsection (f) to 26 U.S.C. 5841 providing that, for any State or local short-barreled shotgun registration or licensing requirement that is determined by reference to the National Firearms Act, a person who acquires or possesses the shotgun in accordance with title 18, United States Code, is treated as meeting that State or local registration or licensing requirement.