Although I have 40 hunting rifles, I have weeded down my ACTUAL use guns to 2. I use my 375 Ruger Alaskan for 90% of my hunting. My best hunting load is a 250gr GMX over a max charge of Ramshot. I get between 2675 & 2720f/s. I have 4 boxes of Hornady outfitter 250gr GMX factory ammo and it chronographs 2700 f/s, so I am happy to duplicate the factory speed with equal accuracy in the 20" barrel.
And just to keep from getting bored, I occasionally take my Winchester Extreme Weather in .30-06. I use 165gr GMX bullets in that too. But if forced to only have 1 gun/load, it would be the 375 cause you cant overkill an animal, but you sure as hell can underkill. I practice shooting 3x a week at all practical distances and field positions, and shoot the 375 very well. It took a bit of time to master, but its worth it.