I have killed 3 of them on different safaris. All with a .416 Rigby and 400 grain A-Frames. Two went down quickly and the 3rd was a not so merry chase. Cat bait and food for the camp staff. Had we come across buff cows I would have shot them instead.
The Giraffe was the only animal I have ever killed that gave me hunter's regret. Beautiful, graceful creatures that cause no harm.
Study their anatomy and use enough gun!
