So I went to Mississippi to pick up a receiver. I knew that I could transfer it as a rifle, and not as a pistol, but the FFL had the new form, so I told him to mark it as a receiver and see what BATFE had to say. Well, it took a bunch of calling around on the BATFE agent's part, but after three (maybe four) "I don't know, let me check with someone higher up"s, she finally came back with a no go. I wasn't really surprised, but thought it was interesting that there was some confusion as to whether it was legal or not.