I had a 6.5 Creed in a Savage Mod. 16 Weather Warrior. The rifle shot fine but was balky feeding which I attribute to the sharp shoulder angle. For that reason and the fact that the 7/08 would do what I need and is a proven round I would choose the 7/08.
Most of the cartridges based on the .308W are pretty good on accuracy. If you want a 6.5 maybe try the .260 Remington.
I doubt it. I’ve had several rifles chambered in 6.5 CM, and they’ve all fed smoothly and reliably, despite the shoulder.
I would say the feeding issues was from the gun alone. Just like the RAR's feed like schidt. Not because of what they are chambered for, but because they just feed like crap. I've seen that with some of my friends Savages with cheap mags, Tc Ventures, and other dollar store rifles. Its the nature of the cheap rifle beast. I've had Sako's, Tikka's (T3x and CTR's), and AR10's chambered for the 6.5 Creedmoor, and they fed flawlessly.