Some lack reading comprehension. It's "Pick Your Three Gun Battery fo NA BIG GAME", not which three guns I can live with to hunt everything?
It can vary from where you hunt. Some will need a shotgun, straight walled cartridge or muzzleloader to hunt where they live, others will not. Some can use 22 centerfires, others cannot. Some hunt in thick cover and a traditional lever action works great, prairie or mountain hunters would think a Marlin 336/Winchester 94 is next to useless.
For strictly big game where I live and hunt, Something in the 243/25-06/6.5Creedmoor/270 range would be the light, a 308/30/06/300WSM/300WM would be the medium, a 338WM or 375H&H would be the heavy.
I currently own a 25-06 and a 6.5 Creedmoor - pick 'em. I own both a 308 and a 300WSM - I'll take the 300WSM. I have a 375H&H. If I could only have one - 300WSM. I mostly hunt deer & antelope - could live with either the 25-06 or the 6.5 Creedmoor.
This is the 'Fire. Reading comprehension is not required.
You are correct about where you hunt affecting your choices. If I lived back in Iowa I'd put my .375 Winchester on the list. In various other restrictive states it would be my .45-70. If I lived where I could hut pigs by the sounder I'd have my .308 AR on the list.
We hunt Colorado for antelope, deer and elk and Wyoming for antelope. I could easily go back to using only a 7mm RM, as I did for the first 20+ years, but that wouldn't be as much fun. Centerfire .22 are not legal for big game in Colorado but they are in Wyoming. Mine is a slow-twist that shoots 40g bullets best and 50g OK so I wouldn't choose it for big game rgardless. But take your pick of the bolt rifle mix: .243 win, .257 Roberts, 6.5CM, 6.5-06AI, .280 Rem, 7mm RM, .308 Win, .30-06, .300WM and .338WM. The 6.5CM and 6.5-06AI are heavy barrels so I wouldn't choose them for anything longer than short carry work - definitely no humping the mountains after elk. And my bolt .308 is a short barrel - a joy to carry but not as well suited for the big stuff as some of its brethren. I have a Savage action with no barrel that will likely become a 6.5PRC or .375 Ruger later this year so add those to the mix.
Questions like this are fun to ponder but the truth is you don't need three different rifles for light varminting to whatever. A .30-06 can do it all. As did my 7mm RM for 20+ years.
