I'm not sure if this is the best place to post this but I'll try here and hope for the best.
I was talking with a fellow today and he told me about a source that makes lowers in halves that can then be screwed together to make a complete, functional lower. He told me that because it is not a complete receiver until the halves are screwed together it is not considered a firearm (in the normal context of the term, not the NFA firearm definition) so the halves can be individually shipped between individuals without an FFL transfer. Does anyone here know how valid his statements are in regard to the "non-firearm until assembled"? I was under the impression that the serial numbered part had to be FFL transferred but since a 50% receiver is not technically a receiver, I'm at a loss to understand how they are getting by with this, if indeed it is true. I have not verified any of this because I'm not going to waste a bunch of time researching this if it is just another urban legend.
I'm not interested in a discussion about the longevity or any other functional aspect of a screw build just the aspect of having a way to beat the system, so to speak.