All good informative posts guys. The only thing I can add is "your shot placement at the moment of truth." Under perfect conditions I will hold just behind the shoulder on a broadside shot. "not-so perfect conditions." Late in the evening, in dark timber, bull quartering towards you, You have to make a quick shot. I am going to do one of these three things.
1-Shoot him in the front shoulder?
2-Shoot him in the neck?
3-Pass on the shot and wait for a better shot/another day?
If you shoot him in the neck & hit the spine he will drop on the spot. If you shoot him in the shoulder? He might run? He might drop on the spot? He might just stand there like nothing happened? I have shot elk in the vitals and had them just stand there after the shot like nothing happened. When this happens I shoot again. I will shoot until they hit the ground if needed. I have had a three bulls that have taken two vital shots & they almost got a third shot but they fell over before I could get the shot off. My point is elk aint your typical whitetail. When/If you shoot a bull do not stand there & admire your shot. If he is still standing put more lead in him.

I should mention 90% of the time I elk hunt with a 300-win mag with 200-grain Nosler Partition handloads. The other 10% of my elk hunting is spent with my 7mm.STW with 140-grain Nosler Partitions hanloads. IMHO my 300-win mag is a better elk round. My 300-win mag is also a full 3-pounds lighter than my 7mm-STW.[&:]

Good luck,

WK