RE: 300 win mag
I think for the bigger gameyou're looking to use this for (e.g. Elk, Moose, etc.) a good .300 WM is a fine choice. I have one I've hunted Elk with for several years. With a 180 gr Accubond, partition, Barnes or other bullet designed for penitrating heavier hides / bone and retainin its mass, you put this behind or on the shoulder of one of these animals and it's going to get the job done.
If sighted in at 200 yds center, you've got well out to 300 yds with plenty of power in the bullet to take out shoulder and penetrate through lungs.
The initial zeroing of the .300 WM is a bit of a challenge. But if you do the bore sighting first you should be able to minimize that. Then from year to year, I mostly have to just check that the scope is still on and now more than a dozen shots at that. I honestly never feel the recoil of my .300 WM Tikka T3 when I'm focusing on and taking the shot on an Elk.
Good luck!