I've toyed with a gazillion cals like all of us, invented several wildcats in the dimmer hours and ordered the reamers therefor to recreate what's already happening- differently. In the end, for those of us who enjoy hunting more than shooting, who else has to sit back and laugh? All the usual suspects caliber wise, in the end, do the same thing inside 200 yards, heck for the most part 400 yards. I've agonized over my dislike for the .277" bore on peculiar concerns such as minimally smaller bullet selection than the 7mms, or minimally poorer BC's than the 6.5's... only to have a .270 in my lap after trades and find that heck, it's as good as any .260, .280, or .300 WSM at dropping a buck.
I've come to see that since the technology is the same- launching a bullet via the pressure of burning powder down a rifled bore- that essentially within the realm of all the usual choices all is identical. The variables left are the shooter, and bullet construction. Whether you're shooting a TSX or a cheapo C&C has shown itself to matter far more than whether the rifle is a .270 or a .35 Whelen or a .303 for me. This said, I do believe sectional density matters, but nearly all calibers in the usual range have high or at least reasonable SD options.
Now, my choices are a lot more tame than they used to be; I want to be able to feed it, therefor components must be readily and affordably available, and well, that's about it. Gone are my exotics as anything feedable means it's established; proof enough it works without splitting the hairs of .270 and .280. Also, so few of us hunt outside 400 yards all the minute trajectory differences between say a .270 and a .308 become meaningless. I'm guilty of splitting a million hairs myself, even started threads on the matter. But in the end, doesn't it all start to look a bit silly? Every cartridge has a case, powder, primer, and a bullet. The usual choices are all of comparable effect and became a 'usual choice' through being a sensible middle ground. I'm starting to think more of our hobby is arguing about differences that essentially don't exist than shooting them! I'm as guilty as the next guy, and vow for my choices will become much simpler and more boring. Hopefully my rhetoric will too as a result!