Someone mentioned M&A Parts earlier. Not sure what their reputation is nowadays, but I bought a 20" Varmit kit off those boys a couple years ago and I am extremely happy. It's just a bench rifle, though, with a Nikon M223 scope and Nikon mounts. I use Nikon's "Spot On" website for ballistics, which is just about the coolest thing. Oh, I dropped in a Timney trigger for s&g's.
Good luck on your build, but if you are just getting in to this stuff remember to be safe. An upper from M&A is properly head-spaced and test fired before leaving the factory.
Good luck on your build, but if you are just getting in to this stuff remember to be safe. An upper from M&A is properly head-spaced and test fired before leaving the factory.