The 6mmARC is basically the 6mmAR cleaned up and legitimized. I have been lusting after that one for a while, just didn't want to put up with all the wildcat stuff. So for me it's a no brainer, I'm jumping in. It should shoot flatter than the Grendel and stay supersonic to further distances. Either a 100grain 6mm or a 130 grain 6.5mm or 160 grain 7.62, I don't think that coyote or deer would tell the difference. Dead is dead. I like reaching out to prairie dogs, so I prefer the flatter shooting 6mm.