Speed most definitively is the way to kill cats I am told (and read). My friend Allen Day is on video with Mark Sullivan executing a one shot kill on a Cape Buffalo with his 300 Win Mag (his 458 had broken the extractor). Allen related to me Sullivan allowed him to do so because Allen could shoot.
Speaking of Sullivan, I asked him about two specific kills on his videos on lion, one with a 30-378 and a 378 (both Weatherbys of course). Both cats were huge but when shot with those calibers, they curled up and shivered as if electrified. He also has many other kill shots on lions with doubles, 375s and 400s, in fact, over a dozen. None of them dropped like with the two aforementioned Weatherbys.
I also have John Sharp on video with a client using a 303 on a Buffalo, took him about seven or eight shots, all perfectly placed to knock him down. Shot placement is of course paramount, but banking on just that and using a "good enough" caliber on game is asking for trouble and that goes for any game. Like everything, this is just my opinion, based on my knowledge and guided by experience (which ain't much).
