It Seems like people are really happy with White Oak Armory Uppers, I looked at them and the only thing I dont like is the 18" heavy match uppers with Free float HG's dont have threaded muzzles, other than that another fine example of a good quality low cost match upper that should get you Sub MOA
WOA will thread the end and install a flash hider or brake if you want one. I did not want one because I won't be going into battle at my age (69).
PS: Here are 5 shots at 100 yds. which are less than 1/2". gun) - - - - - - - - - - - -