Requires background check and Department of Justice authorization to purchase ammunition. Prohibits possession of large capacity ammunition magazines. Establishes procedures for enforcing laws prohibiting firearm possession by specified persons. Requires Department of Justice's participation in federal National Instant Criminal Background Check System. Fiscal Impact: Increased state and local court and law enforcement costs, potentially in the tens of millions of dollars annually, related to a new court process for removing firearms from prohibited persons after they are convicted.