The Hughes Amendment to the Firearm Owners Protection Act (FOPA) made the transfer of machine guns that were not registered for transfer previous to the date that the Act was signed into law illegal for private ownership. From the institution of the Gun Control Act of 1934 until the signing of the FOPA in 1986, only two instances of a legal, privately owned machine gun being used in a crime were recorded. This is a law that severely restricts a class of weapons that have been historically proven to not be used in criminal activity.
Before and since the FOPA, illegally owned and/or manufactured machine guns have been used in multiple crimes. The only effect that the FPOA has had on the average citizen is to insure that they cannot afford one. Criminals do not register their illegal firearm