There are a lot of variables. Everybody thinks about velocity and energy, but there is also momentum.Or high country or plains deer.
It was my understanding that the smaller dimension calibers, while perhaps not as good at breaking bones, penetrate most tissue just as well because they are narrower profile going faster. Think of a fast jab with a hypo vs a slower push with a pencil. IDK, I actually agree with the side that says size doesn't matter!
it isn't the diameter of the projectile that affects penetration as much as the mass of the projectile.
A smaller diameter projectile, all else being equal (ogive, mass and velocity) will penetrate farther because it has less resistance from smaller frontal area and greater sectional density.
But the .300 win mag shoots 180 grain and larger projectiles. More mass penetrates farther because it has more momentum - this is especially true with denser tissue or bone. An elk has larger bones than a deer - it can easily weigh twice to more than three times as much so it needs and has larger bones to support that weight - larger muscles too.