Off the NRA website regarding Illinois gun laws:
Machine Guns
It is unlawful to sell, manufacture, purchase, possess or carry any weapon from which more than one shot may be discharged by a single function of the trigger, including the frame or receiver of any such weapon.
It is unlawful to sell, manufacture, purchase, possess or carry any combination of parts designed or intended for use in converting any weapon into a machine gun, or any combination or parts from which a machine gun can be assembled.
There is an exception to the above prohibition, providing for the manufacture, transportation, and sale of machine guns to law enforcement and military personnel for official purposes, provided such weapons are “broken down in a non-functioning state or not immediately accessible.”
-Safety is no accident, unless you accidentally leave the safety on when you intend to shoot.