Laws regarding AR pistol upper

[that one guy]

What?s the laws regarding AR pistol uppers?

[Capybara]

Not a good idea to have one laying around unless you own a registered pistol lower? As long as you own a pistol lower, nobody can nab you for constructive possession.

[tabascoz28]

There was probably a time that you could have a pistol lower without a mag lock. That's not me, I got mine a few years ago hoping one of the challenges in the courts would be resolved. It hasn't.

Pistol uppers also may be gassed differently so if your plan is to switch stuff out, get an adjustable gas block so you don't have to mess around with different buffers. I had to run a heavier one, especially for the 9mm blowback, first time I felt finger slap.

[ar15barrels]

What?s the laws regarding AR pistol uppers?

Pistol uppers are no problem as long as you also possess a pistol lower.

Pistol uppers are no problem if you do not possess any AR rifle lowers.

Possessing an AR pistol upper without an AR pistol or SBR or MG lower is federal constructive possession of a short barreled rifle if you also possess AR rifle lowers but do NOT possess another lower that would be legal to use with the AR pistol upper even if you NEVER actually assemble an illegally configured gun.

Put another way, always have a "path to legality" for everything you possess and you are unlikely to have legal problems.