So I'm going to start a new build and I want to keep the barrel at 20". I haven't played with a 6.5 yet so I think I will now. Which would be better a 6.5 Creedmoor or 260 Remington, would I even see a difference between the two? I would lean towards the Creedmoor. I don't think I need a ton of velocity from it, it needs to get to 600 yards and the very occasional 900+ but at altitude like 9000'. I was thinking the 140's going 2600-2700 should get me there. Is that a resonable velocity number from 20"? Does one get any better brass life than the other? And it needs to feed from an AICS magazine. Thanks