I have been reading and researching about Form 1 conversions of a rifle lower to an SBR. But so far, no matter what I read, I can't seem to find a clear answer to what I would like to do: And that is--buy a complete factory lower from a name brand manufacturer (i.e. BCM, LMT, Colt, etc) and then go through the process of registering it as a SBR using Form 1. I would not own an upper with this lower. I would be buying only the lower. So, is it possible to register a factory complete lower purchased without an upper as a SBR? I realize that for some of you I am only showing my ignorance by asking this, but I am a retired attorney and I have studied the legalities until my mind is spinning. If someone out there knows the answer, please, HELP!!