I've only thumped a couple of deer with my 308, but I came to the calibre late in life as they say.
If you drive a 165gr. Partition at an easily obtainable 2650fps(22"bbl)
And set things for 3" high at 100yds.
You end up only 6.75" low at 300yds, and packing 1522ftlbs, of energy.
That's more than enough gun, bullet, enregy, and a small enough drop to knock 'ol Bullwinkle on his @#$% no problemo.