I was hoping someone could point me in the right direction for some legal help. Can I build a pistol out of my 80% lower, or do I need to use a designated pistol lower. What are the main design differences between the pistol lower and rifle lower? Does it make a difference if the lower is billet rather than forged? I've got a KT lower that has been sitting around for way too long that I want to try and finish. I now have access to all the metal tooling I need to complete it. I was thinking of buying a 10.25" commando upper and putting on it. As long as I don't have a forward grip and stock everything is good, right?
Thanks
Junglerogue

Legally speaking the "pistol" marked lowers mean absolutely nothing.  The only thing that matters is that the receiver was never built as a rifle.  

I would say that because you aren't manufacturing a lower for sale and it doesn't need to be registered, yo are fine with it being a pistol or rifle. They are the same in all dimensions. Billet vs. forged are highly and scientifically debated near daily (both work).

Build it up and post pics, just be sure you don't have the correct components to assemble a SBR without it being registered.