That's not entirely true, as the way I understand it with lightly jacketed varmint bullets, the added twist is essentially stressing them a bit more, causing quicker upset when they strike flesh.
I've seen the fast twist help provide more "lift" when striking small game while shooting slow and fast twist rifles of the same cartridge side by side, in such rounds as the 223, 223 AI, 220 Swift, and 243.
I'm just not convinced it really shows up on big game. "Lost in the noise" as it were.
