I have heard that some elephants shot in the head with a 700 Nitro were not knocked down.

However I did miss the brain of an elephant once at @4 yards with my 450 No2.
I stepped out in front of her at @3 yards. Instead of dropping her head and comming she stopped,reared back and began to turn.

I fired the right barrel.

It knocked the elephant down, from the actual fall, it looked as it was unconsious, and the second shot was fired into the chest from the front at a quartering angle.

WE, The PH and I were concerned with other elephants for a few seconds, more shots were fired, over their heads, which worked to stop them and turn them away, the shot elephant got up and headed away. Two shots to the rear had little effect, a reload and a shot to the side brain finished the deal.