In 1989, the Bureau of Alcohol, Tobacco and Firearms (BATF), with the support of President Bush, banned importation of 43 "semiautomatic assault rifles." [29] According to the BATF, these weapons lacked a "sporting purpose" as set forth in 18 U.S.C. 925(d)(3). [30] The BATF Working Group identified assault weapons using the following criteria: military appearance, the likelihood that they were originally, or could easily be transformed into, fully automatic weapons, and cartridge size. [31]

Seven features were considered in determining military appearance:
(1) large capacity magazines that enable the weapon to shoot more rounds without reloading;
(2) folding stocks, which provide better concealability and portability and which are not generally present on traditional sporting rifles;
(3) pistol grips, which enhance control when firing with one hand, a maneuver not generally used in hunting;
(4) flash suppressors, which conceal the shooter's location;
(5) bipods for stability;
(6) capacity to accept bayonets or grenade launchers; and (7) night sights (since nighttime hunting is generally illegal).
[32] The Working Group also examined whether the weapons originally had been, or could easily be transformed into, fully automatic weapons. In general, guns that were originally fully automatic were suspected of having been transformed into semiautomatics solely to evade import laws and thus were classified as "military" in nature. Meanwhile, to help identify a weapon's overall sporting purpose, the Working Group examined advertisements and articles about the weapons and sent out questionnaires to experts, magazines, and shooting clubs. [33]

Using these criteria, the BATF classified forty-three weapons as assault weapons. In so doing, it established a non-arbitrary method for distinguishing assault weapons from other semiautomatic weapons.