pick_six wrote:Also, if you start from a stripped lower, how would anyone know or prove it was anything but a pistol first? The silliness of federal gun law.
If the stripped lower left the manufacturer as a stripped lower, it would have been registered with the ATF as an AOW (any other weapon). These can be made into either a pistol or a rifle without paperwork. If you bought a finished lower (stock, pins, and trigger), this is registered with the ATF as a rifle and it can not be made into a pistol without filing the correct paperwork.
The only way they'd prove it is if they contacted either the manufacturer, or the ATF and sought the information on how it left the factory.
This is worth keeping in mind if you ever buy a stripped lower second-hand. Did they purchase it that way, or strip it out of a prebuilt rifle? It'll matter if you ever want to build it as a pistol and stay on the right side of the law.
I actually registered one of my pistols as an SBR (HK USP) just in case I ever wanted to pick up one of those stocks that fits around the pistol. I also have an Kriss Vector and a DPMS lower registered as an SBR. It's a pain to do, but I think it's worth it.