essohbe/Nick9130White:
As for just the appearance/sound of full auto operation, a Wisconsin guy went to prison after he loaned his AR-15 to a guy, who took it to a Wisconsin range.
The gun had Not been altered, but after the rifle's malfunction made it Appear to go full auto for a few rounds, somebody must have called the ATF.
I don't know which website had the link to the news story.
The ATF persuaded the judge not to allow a firearms expert to testify about the known malfunctions, from what I remember
reading (a year ago?).