A friend of mine that I work with is in the "being drug along" stage right now with AA. I think he is going to order a barrel from Black Hole so he can build his now.
He blames me, as my wife has one and that is why he got interested in that caliber. I told him from the start to go with the Black Hole barrel, or just get a 25WSSM upper.
You will love your 6.5 Grendel. My wife sure loves hers. Neither coyotes nor antelope are not so fond of it however.
I am looking at building either a 6PPC (I believe the parent cartridge of the Grendel), or a 6 DTI, (6.8 SPC necked down) for my next project.