I just built an ar pistol in 556 with a 7.5 inch barrel. Now I know if you have a pistol upper you have to have a pistol lower if you have rifle lowers or its a constructive possession issue. Now that I have multiple complete ar rifles and one ar pistol, can I have multiple pistol length uppers for the one pistol lower?
Stupid question, but covering my bases, as I want a 300blk shorty upper to switch back and forth on the one pistol lower.

