Trying to decide on a 20” grendel Match Barrel

[FLshooter]

I just got off the phone with Mark at precision firearms.
He recommends a 24 inch Krieger heavy barrel .Said it’s his best barrel and gets best groups .
I was wanting a 20 inch medium contour barrel but I also want half inch groups@100 yrds and I’m going to shoot it at the 600 yard range .
There is no difference in price between a 20 or 24 inch barrel. At this point , i’m not ready to order yet .I would appreciate some more feedback.