Here’s where you need to understand the difference between automatic and semi-automatic. Semi-automatic weapons are relatively easy to purchase. However, the only automatic weapons legal to purchase for civilians in the United States are the ones that have been registered between 1934 and 1986. According to the Bureau of Alcohol, Tobacco, Firearms and Explosives, an “assault rifle” (or automatic weapon) is a machine gun. No new machine guns can be made or sold to civilians. Automatic weapons have been heavily regulated since the National Firearms Act of 1934. Taking possession of such weapons requires paying a $200 federal transfer tax, filling out an application to register the weapon, submitting passport photos, getting your chief law enforcement official to sign your application, and submitting to an FBI background and fingerprint check. Those weapons are hard to come by and generally pretty expensive. You do not want to violate the Firearms Act. If you do, expect to sit in prison for 10 years as you figure out how to pay the $100,000 fine.