I agree for shooting the 140, heavier bullets, the 6.5 Creedmoor looks like the cat's meow. However, I should have clarified, I would limi bullet weight to 120/125, like I did in my previously owned 6.5/284. I loaded to to 2.78" and in a 24" bbl got right at 3200fps, it was a real killer, flat too. But that last round would give me fits, never did feed right.
I've also seen 6mm Remingtons in Model 7's, so a 6.5/57 Improved might be doable in a Model 7 action. I'm just brainstorming, typical Wildcat disorder, ha.