It seems that the KO value has been incorrectly reported on. I've read Taylor's work on it and he never says that he used "missing an elephant's brain by a small amount" as the criterion for developing the KO values, he just uses it as one of several examples. The value is also limited to just "massive" animals like buffalo, rhino, and elephant.
It appears that the KO value is misunderstood. He was using his experience in hunting to rate the actual effectiveness of heavier bullets on massive game. He never suggests that KO is a general theory of effectiveness. The context of the KO value is that Taylor saw muzzle energy as a poor measurement for evaluating killing power of bullets on massive animals and was looking for an alternative. His opinion was that bullet weight was not given adequate credit in the formula.
Essentially he is saying no more than that fast, heavy bullets that penetrate adequately at typically close ranges are superior for massive game. I don't think anyone disputes that today.
