Ok, so I want to change my AR-15 to Fully Auto. Before anything else is said, I know that I need to know someone with a FFL to ge the parts. (Got that part) And I know that it has to be registered as a class 3 firearm. (I know how to do that) But what I dont know is, What parts do i need to convert??? Also this is a pic of the wep I want to convert. "If it helps any its a Bushmaster XM-15 E2S"