In the United States, assault weapon is a controversial term used to define firearms with specified characteristics. The definition varies among regulating jurisdictions, but usually includes semi-automatic firearms with a detachable magazine, a pistol grip, and sometimes other features, such as a vertical forward grip, flash suppressor, or barrel shroud. Certain firearms are specified by name in some laws that restrict assault weapons. When the now-defunct Federal Assault Weapons Ban was passed in 1994, the U.S. Department of Justice said, "In general, assault weapons are semiautomatic firearms with a large magazine of ammunition that were designed and configured for rapid fire and combat use." The commonly used definitions of assault weapons are under frequent debate, and have changed over time.