I think you will be disappointed.
Expecting that accuracy from that type AR just isn't going to happen with a human behind the rifle.

Having said that, the most accurate barrel would be a high end custom with a tight match chamber and properly headspaced bolt. Why do you need a .5 MOA SBR???


John 8:12 "I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life."