I used a single 154 Spire Point in my .280 Ackley, loaded down to 2800 fps, to kill an Asian water buffalo a couple of years ago. Perfect double carotid artery hit and an exit hole in the far side of the neck of about one-inch.
A single well-placed bullet can do magic.
I've killed lots of deer and several elk with the Hornady 154-grain Spire Point Interlocked. It is a wonderful bullet in all possible ways.
In thinking back, I cannot remember ever having the need to shoot twice on any big game animal I've killed with a 154. Nor can I remember a critter struggling more than a few yards.
Heck of a bullet.
Steve