Not looking for a rifle to use at the range. Hunting, and I guess if SHTF scenario I could use it. Wouldn't be used as my primary home defense gun either. Price for rounds isn't really an issue. Which would you choose and why?
Are you sure price per round isn't an issue?
I looked into this also, and the deciding factor was cost of ammo, and availability.
.458SOCOM sells at roughly $3 a round. Too much for my tastes, although I loved the idea of an AR chambered for it. Basically a .45-70 in an AR platform.
.300BLK ammo is much cheaper and very available, and would be a great short/middle distance hunter, as well as a SHTF rifle.
I built my second AR as a .300BLK as a result. For more power at longer range, my next build will be a 6.5Grendel.