I've taken two, both with my 340 and 225 TTSX bullets, first one was shot right in the pocket tight to the shoulder, but I didn't see that the shot angle was a bit quartered to. Bullet placement was perfect, clipped the back of the heart, (but just clipped), and clipped the bottom of the lungs. Bull was running off and second shot went high and shocked, but did not break the spine. When I got to him, he was getting back up and ready to fight, turned a bit and third shot broke both shoulders. Whew!!! Most unwilling animal I've ever seen.
Second nilgai was also quartering to, but I knew this. Bullet broke the near shoulder, destroyed the lungs. DRT.
Shoot them with a VERY strong bullet, smack in the shoulder as one would with African game.