Well, I normally hate 6mmās because most are very overbore, to a point where a .257 or 6.5mm would be the much better option... Examples being the .243 Win/6mm Rem vs. .25 CM/.257 Bob vs. 6.5 Cm/.260 Rem.
That said, Iāve been heavily invested in 6.5 Grendel for like 15 years now in the AR world, and always said it would really shine in a bolt gun. Well, my past experiences with Howa, and recently with the Ruger American Ranch have not been so positive, so I was a bit depressed that nobody has been producing good high-quality 6.5 Grendel bolt guns. I would love to see a Christensen Arms Scout or MPR in 6.5 Grendel. And since the 6.5 Grendel and 6 ARC share the same parent case (bolt face) and the same MDT magazines, it would be SUPER easy for Christensen to make a 16" 8-twist 6.5 Grendel rifle. Plus, if I don't like this 6mm ARC, I can always rebarrel it to a 6.5 Grendel with a simple barrel swap, since everything else is the same.
Well, along comes the 6 ARC, and at first I thought it was the dumbest thing ever, because it's basically just a 6.5 Grendel necked-down to 6mm, and there weren't really anything but varmint bullets out there for 6mm (to my knowledge, as I had not really researched them)... Aaaaaaaand, then I found out that the standard twist for the 6 ARC was a 7.5" twist, and that several companies are now making 103-115gr. 6mm bullets. So, I decided I couldn't really pass up the opportunity to grab one, since my local store had it in stock. No recoil, and amazing ballistics, with lots of very heavy-for-caliber high-BC bullet options now, and still retaining good velocities, and I can reform 6.5G brass in a pinch, if I need to... It would be a great coyote and varmint rifle. So I decided to pull the trigger on it to match the MPR .308 Win.
I was a huge 6mm ARC hater from the very beginning... It's what pissed off Jeff Broz and got me banned from LRO. But I'll admit when I'm wrong. That said, I still maintain my position that the 6.5 PRC is a useless barrel-burner (unless you plan to ONLY shoot 150-160gr. bullets)... In which case, you might as well buy/build a 7 PRC that shoots 140-200 grain bullets, and get something worth owning. Just my $0.02.