As long as it is over 1800 fps the expansion is still violent and aggressive in Berger with my experience. At high muzzle velocity out of my 7 and 25 short mags with Berger I get carnage and tennis ball sized pass throughs. With chunks of lung getting pulled out at 100 yards.One of the issues with match bullets is the expansion is related to velocity and as it decreases expansion changes. The change is USUALLY a good thing.....until it's not.
On any traditional broadside shot, shoulder or ribs, velocity over 1800 fps any partition or hunting target bullet will expand and kill.
I purposely said that the penetrating quality of a partition loses effectiveness on less than ideal shots where you need deep penetration because of shot angle, which relates directly to the 600 yard shot on topic.
A 6.5 at 2800 fps mv is at about 1850 at 600 yards. So a 6.5 creed or 260 is at its limits. A magnum pushing 3000 fps is more better of course.
Everything is a tradeoff and very situational.