May sound stupid, but I've been sitting here this morning trying to come up with a way in my mind that the average homebuilder could make a bent sheetmetal lower receiver that utilized standard AR components, and would mate up with a standard AR complete upper? Doesn't necessarily need to look like your standard milled lower mind you. Maybe like an AK style grip and trigger guard, weld on buffer tube mount, steel blocks welded or riveted in as structural members to hold the width, and to support the upper pivot pins, sheet metal magwell utilizing standard AR mag release. Seems doable in my mind, if not necessarily practical. One of those "do it because you can, not because you have to" kinda things. I think it would be an interesting experimental build. Kinda cool to make your own lower, and it not be like an 80% lower that you finished, but actually built completely.
Am I totally out in left field? Is there some critical piece of the engineering puzzle that I'm not thinking about, that's a show stopper? Not necessarily saying that I'm gonna build it, just trying to figure out if it's possible.
What say you, O great AR gurus?