RE: which gun? 30-06 or .300 magnum
I have shot a couple 300 win mags, WOW, I hate that recoil.
I bought a Marlin MR7, 30-06. My friend hand loaded me up some 150gr, pushing them at just under 3000 fps. Plenty accurate for deer out to 300. Would go bigger for blackbear, don't know about moose. I can shoot the 150 gr all day long, the 185 gr he handloaded starts to kick good.
I always view the 300 as a 300+yd gun, under that the 30-06 should work well enough as long as you can shoot it accurately (which less recoil will help with).
--Jim