He proudly exhibited the rifle that was used to make the kills - a single shot .22 bolt action rifle!
That's one way to do it with a .22. Another is up the nasal cavity. Then there's the trick with a 12-bore shotgun, inserted up the rear after lifting the tail, suppository fashion. Marksmanship is not an issue, and the damage is done by internal haemmorage from the expanding powder gasses, with the type and direction of the shot load of less importance. The primary factor in the choice of shooter for that sort of most rude slaughter aside from stealth, is that the shooter be the fastest runner possible, for obvious reasons. And the more the beast runs, the more it injures itself, with death coming after two or three days of agony.
There was a kill of a circus bull in the US in the mid-1960s using a .22 short, by a drunken rube showing off his handgun to his lady companion. Imagine his surprise upon being presented with the bill for his localized safari, following the beating he received from the animal's handlers.