The National Firearms Act of 1934 makes it illegal for civilians to own machine guns without permission from the Federal Government. The National Firearms Act of 1934 levies a $200 tax on each newly manufactured machine gun and a $200 tax each time the ownership of the machine gun changes. In addition, each machine gun is registered with the Bureau of Alcohol Tobacco and Firearms (BATF) in the National Firearms Registry.

To purchase an NFA weapon, you must submit two sets of fingerprints, a recent photo, a sworn affidavit that transfer of the NFA firearm is of "reasonable necessity," and that sale to and possession of the weapon by the applicant "would be consistent with public safety" and endure a background investigation. In addition, the application must be signed by a chief law enforcement officer with jurisdiction in the applicant's residence.

The National Firearms Act also regulates shotguns with barrels less than 18" or less than 26" overall length and rifles with barrels less than 16" or less than 26" length overall. The National Firearms Act also regulates firearm silencers. In addition the National Firarms Act regulates destructive devices such as bombs, grenades, rockets, missiles, and mines.

The text of the National Firearms Act as amended is available online at: U.S. Code Title 26, Subtitle E, Chapter 53: Machine Guns, Destructive Devices, and Certain Other Firearms.