I'm struggling to understand how this is even a question...
I sometimes wonder if WWll had anything to do with it. The 30/06 for human targets in all scenarios. And then all those vets coming home and hunting the ubiquitous whitetail deer with it imbedded it into the mental climate of the culture as the ever-after human, deer-sized creature cartridge. Which it is good at but not necessary.
Then in the 50’s and 60’s and on even into the 90’s you have writers like Bob Hagel, Bob Milek, and and others waxing on the 338, 340, and the 375 for elk and moose and it seems reasonable that for these big animals a cartridge-size increase was needed. Proportion, you know. And it was probably true to some extant due to poorer bullets. I bought into it in the 80’s and 90’s having hunted with a 340 for two decades. It was lethal but not necessary.
As the it’s-the-bullet-not-the-headstamp era dawned on the loons, it became obvious that smaller, “lesser” cartridges thus loaded were more than adequate. Yet the perception that bigger for elk is always better remains.
Obviously, the military figured out that the “small” 5.56mm was lighter to carry and adequate for killing or maiming (even better because you don’t have to kill an enemy but maim him to burden the whole system) humans. Obviously, maiming doesn’t transfer to hunting game animals.
I killed my last 6x6 easily with a hand loaded 284 Win.
