I am putting together a precision build, not a battle rifle, and have a few questions on a upper receiver. I am looking to get the most accuracy I can out of this setup. I have a Krieger 20" DCM barrel. I have read about Vltor MUR A-1, Raineir Arms Billet Ultra Match, Larue Stealth Upper and also the Mega Billet upper. I am wondering which might be best from an accuracy standpoint? Any real difference from a standard forged upper? I have read about the thicker wall and truer dimensions. I am not really worried about the cost, just looking to get the most accuracy I can. I have a good deal linned up on a Mega Billet set, but was wanting some people to chime in with real life experience. Again, this build is to make a real tack driver so small differences mean something. Thanks much.
   

You wont gain any accuracy with a billet upper. They are not worth the extra $$$ IMO. Go with a standard $95 upper. I also bought a receiver face lapping tool and squared off the front of my receiver. I dont know how much difference it makes on an AR but it cant hurt.