[Aguila Blanca]

A few years ago there was also a vendor of 80% AR-15 lowers who was also a manufacturer of actual, 100%, serial-numbered lower receivers. As I understand it, on Saturdays they would host 80% days -- anyone local enough to make it to their facility could come in, pop their newly-purchased 80% receiver into the comapny's CNC machine, push the button ... and however many minutes later out would come a finished AR-15 lower receiver.

Somebody blew the whistle on them, the BATFE got involved, and I don't recall the details. The result, per my fuzzy recollection, was that the BATFE ruled that when they said people were allowed to complete the final 20% themselves, that meant the people had to complete the final 20% themselves. Putting the receiver in somebody else's CNC machine, programmed with somebody else's program, and just pushing the START button doesn't qualify as finishing the last 20% yourself. To be honest, I don't have a problem with that. To me, doing that (if that is, indeed, what they were doing), does strike me as skirting the letter (not to mention the intent) of the law.

Then somewhere along the way I heard or read that the BATFE had extended that to mean that even if you did all the work on a traditional Bridgeport milling machine, you had to actually own the machine. I'm a lot less sure about that, and I don't know how to verify or refute it.