Either one would be fine. I've had Colt MTs that would shoot 3/8" with no other tweaks but a good scope and Black Hills match ammo. This
is what I know about the Compass Lake chamber. I've not owned a Windham, but have every intention of getting one in the next few months. Based on what I've seen and read, I think they are, arguably of course, one of the best ARs out there for the money.