did you ever get the AFG issue resolved?
I got an email form the batfe saying that they would forward my question to the correct department, then give me an answer. I asked two different guys that worked at local shops and they both said that the AFG would make it an AOW... so I'll probably just avoid it and save the AFG for a rifle.
is mine and it only cost me $340....Yay me!!!! http://www.gunbroker.com/Auction/ViewItem.aspx?Item=185207286
was a link to that question on m4.carbine,i lost it now,but it seems the lower has to be registered as a full auto,then you can use an AFG on a AR pistol,if you go on m4 hit the search option and ask,that's how i came up with what little info they had.