Performance. I am one that likes the AR platform and have about 6 calibers but I would not take one in 6 Arc. I am interested in the Arc but intend to have it in a bolt rifle.
If it fits my needs why do I need to use something that is "better"?
I have personally explained the reason why I chose to buy TWO bolt 6mm arc's is because I don't need the "extra" of a 6mm CM and I wanted something different than a 243.
I shot a bolt gun in HP rifle competition for some 20 years (after shooting Garand for at least 5). It is a common belief that bolt guns are more accurate than gas guns, and if you're shooting those bughole benchrest matches, that is true, but, a good match Garand is capable of sub MOA which is good enough for XTC matches. I was enlightened when some AR's started appearing on the line at matches and soon impressed by the scores their shooters turned in.
As far as hunting accuracy (MOA 5 shot groups in my book), I've built two AR lowers and used PSA uppers to complete, both shot MOA groups. A Bushmaster Predator shot sub MOA out of the box. This was a 5 shot sight in target and my hunting partner sat down and shot a mirror image 5 shots which would have overlapped my group.
and a Dtech 243 WSSM did the same. Shot the 3 shots, moved up 1/2 MOA and shot third shot hitting POA. So don't sell the AR's too short.