Originally Posted by Hef
No. That would be an unregistered SBR. Even owning a lower receiver (stripped or complete) and a short barrel upper (whether sold as a pistol upper or not) would be considered an unregistered SBR.
Apply, wait for tax stamp, then build.
I'm waiting on my tax stamp for a 10.5" AR SBR. My examiner told me that they're really busy so it will be a few months.
If you have a virgin stripped lower you can build a pistol out of it if you wanted. To do so (if a pistol AR is legal in your area) would not require a SBR Tax Stamp.