I have a Cooper in 6.5 Creedmoor. I have shot 140, 130/129 and 120gr bullets. All have performed very well.
My most accurate load and most consistent velocity load is 130gr Berger, Hunter powder(yea, Ramshot), and LRM primer. I'm actually jumping it rather far as well. Around .040, if I remember correctly.
I've shot 140 Amaxs, they did well. Not quite as good as the Bergers. Also have used 129gr SST. RL-17 gives best velocity for me, use with 129's for hunting. Hunter comes close to RL-17 velocity for me. But better groups. H-4350 shot well, gave up over 100fps from Hunter, and did not match Hunters SD's.
Every load has easily been sub MOA, the Bergers will usually shoot around .300 or less. Unless I drink to much coffee, then a bit more. I am the weakest link by far with this rifle.
Good luck, have fun.