I just came across a super deal on a AR15 from one of my friends. The only problem is the guy he bought it from is a Class III holder and modified it to use M16 parts (burst) When the Class III guy sold it to my friend he removed the auto parts and reinstalled the legal AR15 parts. The reciever now has been permanantly changed by grinding/drilling. Is the reciever by itself illegal in this form. If it were anyone else I would not bother but I trust my friend and he is giving me a good deal. It would not be to my advantage money wise to buy another reciever and swap out the parts.