I would select a different barrel. I'd look toward somebody that makes complete AR bbls that are ready to shoot. I'd consider somebody like Satern, Shilen, etc.
For the bullets you intend to use, most would recommend a 1:7" or 1:8" twist rate.
"Tomorrow is the most important thing in life. Comes into us at midnight very clean. It's perfect when it arrives and it puts itself in our hands. It hopes we've learned something from yesterday."