The Federal Assault Weapons Ban, a provision of the Violent Crime Control and Law Enforcement Act of 1994, expires due to a 10-year sunset provision. The ban defined and outlawed the sale of semiautomatic “assault weapons” and magazines capable of holding ten or more rounds, and prohibited the possession of illegally imported or manufactured weapons. Supporters of the ban said it aided police officers and reduced gun violence; opponents said its provisions were arbitrary and ineffective.