(4) extraordinarily destructive ammunition for these weapons, including armor-piercing and armor-piercing incendiary ammunition, is freely sold in interstate commerce; and
(5) the virtually unrestricted availability of these firearms and ammunition, given the uses intended in their design and manufacture, present a serious and substantial threat to the national security.
SEC. 3. COVERAGE OF 50 CALIBER SNIPER WEAPONS UNDER NATIONAL FIREARMS ACT.
(a) IN GENERAL- Section 5845(a) of the Internal Revenue Code of 1986 (defining firearm) is amended by striking `(6) a machine gun; (7) any silencer (as defined in section 921 of title 18, United States Code); and (8) a destructive device.' and inserting `(6) a 50 caliber sniper weapon; (7) a machine gun; (8) any silencer (as defined in section 921 of title 18, United States Code); and (9) a destructive device.'
(b) 50 CALIBER SNIPER WEAPON-
(1) IN GENERAL- Section 5845 of the Internal Revenue Code of 1986 is amended by redesignating subsections (d) through (m) as subsections (e) through (n), respectively, and by inserting after subsection (c) the following new subsection:
`(d) 50 CALIBER SNIPER WEAPON- The term `50 caliber sniper weapon' means a rifle capable of firing a center-fire cartridge in 50 caliber, .50 BMG caliber, any other variant of 50 caliber, or any metric equivalent of such calibers.'
(2) MODIFICATION TO DEFINITION OF RIFLE- Subsection (c) of section 5845 of such Code is amended by inserting `or from a bipod or other support' after `shoulder'.
(3) CONFORMING AMENDMENT- Section 5811(a) of such Code is amended by striking `section 5845(e)' and inserting `section 5845(f)'.
(c) EFFECTIVE DATE- The amendments made by this section shall take effect on the date of the enactment of this Act.