I'm in the process of collecting parts to build my first AR upper receiver, in part because I haven't been able to find a complete AR I like that's in stock, so I figure if there is a gun ban at least I can upgrade/backup my current AR parts. I ordered a JP enterprises BCG, and a wilson combat m4 barrel because it's the same diameter as my current DPMS lo pro. This barrel has a diameter of .920 which in my understanding is wider than the typical AR barrel. Does that limit me in my choice of upper receivers? I don't know whether to backorder a Wilson Combat or Noveske upper, or if I shoud go ahead and order an in stock JP enterprises upper, but I'm concerned since JP doesn't make any barrels in .920 that it wouldn't fit. As I say, this is my first build.