what about recoil for a younger shooter for say .300 in deer hunting, .350 is something I have shot but not a fan. also not looking to do .458 or .4506.5 grendel (speaking from experience) is excellent with 2 caveats.
1. You need to be proficient with 5.56
2. 5.56 is MUCH cheaper to practice with
6.5 Grendel nearly doubles your effective range, nearly doubles your energy at all ranges, over 5.56. It, along with 6mm ARC, are great cartridges to maximize the range of the little AR platform. These are apples and oranges in comparison to 300 AAC.
300 AAC is pointless unless you intend to run subsonic with a supressor. Nearly every cartridge out there offers more punch than 300 AAC, and quite a few that offer greater range. For hunting out to 300 yards (depending on the game, Grendel is great), for hunting at near distances several cartridges offer a great advantage over 556 or even Grendel. 458 SOCOM, 450 BM, and 350 legend all offer huge advantage in energy at near distances.