Shot this guy decades ago in Botswana at 21 yards with a 500-450 H&H that was pushing .458/480gr Woodliegh softpoint at 2150 FPS with 5000 ft/lbs of energy. You can see the first shot in the chest, definitely a killer, but he required two more shots before he was down for the count. Seconds seem like a lifetime with 500 pounds of claws and teeth at spitting distance. My second shot hit him square in the chest, with the slug settled just under the skin in his rump with 90+% weight retention and expanded to the size of a quarter. While he reacted at the shots, it didn't take long to regain his sense of fight. Based on this particular hunt and several other game animal taken from Impala to Cape Buffalo, unless the central nervous system is destroyed, knockdowns cannot be counted on.