To me it's not choosing the perfect caliber but the perfect load in a caliber of your opinion. I say opinion because that's all it is. They all will get it done. Even a .243 will consistently kill elk. And if you can't kill elk every time with a .243 then you can't shoot. It's as simple as that. Sounds harsh but the debate of fire power has long grated on the marksman capability to put it where it belongs. The 270 win has became the standard minimum elk cartridge in the recent decades. So anything equal to or above should get a general consensus. I'd buy a 375 H&H if I had any doubts. HEHE