: Firearms like the AR-15 are semi-automatic, meaning they fire only one round per trigger pull. These are often referred to as "assault weapons" in political legislation, but they lack the selective-fire capability of military rifles. Popular Models and Features
: True fully automatic assault rifles have been strictly regulated under the National Firearms Act of 1934 .
Technically, the U.S. Army defines an as a selective-fire weapon (capable of both semi-automatic and fully automatic fire) that uses an intermediate cartridge.
: Civilians can generally only purchase automatic weapons manufactured before May 19, 1986. These require a federal background check, a $200 tax stamp, and can cost upwards of $15,000.