If I wanted to build a fancy AR that could reach out there, I think I'd explore the 7mm Valkyrie. WHY, you ask? I have looked at it and it will do anything the 6.5 Grendel will do. But, I shoot a 7mm 150 grain Game King in my 7 mag and it has a BC of .535 an can reach out there. At 3200 fps, you'd best be at least 100 yards from your target. I've seen that bullet at close range do amazing meat damage and I've seen it fail to shoot through moderately sized whitetail deer at very close range. If I were to keep hunting with it in my 7 mag and didn't want to shoot longish ranges, I think I'd just slow it down. It's a very accurate bullet though. I shot a similar 150 match king from my Contender in IHMSA competition, very flat shooting. I think that bullet might be ideal at 7mm Valkyrie velocities, but the catcher might be the OAL. That's a long bullet in a short action. I have thought about it, though, just to show you I ain't pulling my opinions out of the ether. This proposed load would take some research and experimentation. Not REAL sure it'd work due to OAL. In my 7 mag, I've decided the 160 Nosler Partition is how I'll go from now on. The Sierra is a might frangible for those velocities. The Partition doesn't have the BC, though, but I don't really need it anymore. If I use that cannon, it'll be because the target is big, Nilgai or Elk or something.