<i>full automatic assault rifles are not legal in the US</i><p>That&#x27;s incorrect, they are legal federally, but some states have made them illegal.<p>In order to purchase an automatic weapon, you need to submit a form to the FBI, provide fingerprints, have your local police chief sign-off (or create an LLC) and pay a $200 tax.<p>It&#x27;s a very thorough background check.<p>Not many people buy them since the cheapest weapons cost $10,000 and go up to $50,000.  This is due to the limited supply since civilians can only buy automatic weapons that were built before 1986.