A 6.5mm/140 of equal build to .308/180 will out-penetrate the latter. I just can't see any reason to go beyond a 140 in the Creedmoor, just like I really wouldn't shoot anything more than a 180 in the 308 Win.

The 140 out of the 6.5 CM hull gets all that can be reasonably gotten IMO.

“Perfection is Achieved Not When There Is Nothing More to Add, But When There Is Nothing Left to Take Away” Antoine de Saint-Exupery