Flinch,

I've killed elk with these;
.308 Winchester, 150 grain Power Point-Model 88 Winchester,
.308 Winchester, 165 grain Sierra Boat Tail, Savage 99,
.30-06, 180 grain Nosler Partition, Winchester Model 70's
.338 Win Mag, 225 grain Trophy Bonded Bearclaw,Model 70

Of those, the .338 has become my favorite.