That's going to be a great build, powell, geat part selection! A lot like my recent build and JonM's. Gotta love a BCM middy!
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
You'll remember the quality of a gun long after you forget how much you paid for it.
US Army 1966-69, VFW Life Member, Retired Geek