"What Does a Bigger Cartridge Get You?"
Id say, CONFIDENCE BASED ON PERSONAL EXPERIENCE,
What I see in the real world is that a good deal of the effectiveness of a firearm ,in any hunters hands will be related too the familiarity he has with it,and the amount of previous practice and confidence he has with that firearm.
As Ive stated in other threads I started my elk hunting experience using a 30/06 760 slide action, it killed every elk I shot ,lethality was never an issue, but I had little confidence in that rifle because the first few elk I shot ran after being hit (and hit well at fairly short distances BTW) being young I just KNEW I needed a bigger caliber and bought a 340 wby, I practiced extensively and hand load, and while the recoil had increased it was never a personal issue I considered objectionable.
Your obviously going to ask?
Did things improve?
well it depended on what your looking at,the next couple Elk I hit with the 340wby loaded with a 250 hornady sure reacted differently, most acted stunned, or staggered then fell, rather than running and falling like they did with the 30/06, but from a pragmatic view, a single shot from either rifle resulted in a dead elk rather rapidly.
I tend to TRUST the 33-45 caliber rifles loaded with 250 or heavier projectile,so thats what I carry my late hunting partner rarely carried anything but a 358 win BLR, and he killed 16 elk over 37 years we hunted together before he passed, so power is secondary to the CONFIDENCE YOU HAVE IN YOUR EQUIPMENT, and I could no more select the correct rifle for you than a wife or truck you want!