Also everything I'm doing is completely legal. I'm not skirting the law lol. Federal law prohibits federal firearms dealers (FFLs) from transferring pistols to anyone under 21. It does not prohibit private sales, however in 2014 we passed i-594 which prohibits private purchases essentially.
Federal law does not prohibit POSSESSION or MANUFACTURE. When you finish an 80% lower you are essentially manufacturing a firearm yourself. People under 21 can own pistols. Just needs to be on their own private property. I have a G19 I finished off an 80, I shoot it at the local range that I have a membership with. They're fine with it, I've even specifically asked them about it.