Seems like AR pistols are a massive gray area... So you can convert a rifle lower to a pistol legal configuration? Or pistol to legal rifle? They don't start life as just one and stay just one? And really who checks every serial number in your safe to keep folks legit? Can you own a pistol upper before you own a pistol lower?
What separates a SBR upper from a pistol upper?

Any day I'm above the grass and I'm not a zombie is a good day! JYD#138