I've shot elk with:
70-pound bow, Easton aluminum arrow, Zwickey broadhead
.270 Winchester, 150 Speer Grand Slam and Nosler Partition
.30-06, various 180-200 grain bullets, mostly 200 Partitions
.300 WSM, 180 Nosler E-Tip at 2850 fps
.300 Winchester Magnum, 200-grain Nosler Partition
.300 Weatherby Magnum, 200-grain Nosler Partition
Have also shot a few elk with the .338 Winchester Magnum, but all had been previously shot by somebody else, because I was guiding or "backing up." One really didn't need another shot, since my wife had already put a 150-grain .270 Partition through both lungs. This has always worked, pretty quickly, but the elk was heading downhill, away from a ridge we had to haul it back up.
The only real problem occurred with the 150-grain .270 Grand Slam, an early version (late 1970's) that didn't hold together very well. Later Grand Slams have worked much better.
