I’d have to go with the 7prc for one “do it all” rifle in the lower 48. I drank the hornady koolaid and am a fan boy of the PRC cartridges. 7 PRC seems to be a happy medium and carry sufficient energy for most anything. The recoil isn’t terrible and even better with a brake/ suppressor. 22-24...
+1 for exos k4. The load distribution is even and transferred to your core/ lower extemities. I’ve found the lumbar support and hip belt to be most comfortable when compared to some of the other packs, although I haven’t carried weight and been on extended trips with others.