The best alloy for cavitation control at high velocities is about 30% WW 70% lead, and I spelled out that alloy primarily for those who will be using a single alloy bullet for hunting and want to drive it at the highest speed possible and still retain enough weight for good penetration.
Straight WW is excellent for softnoses, with the shank hardened much as necessary to control breakdown at the velocity of interest. In other words. If one is only interested in 2000 fps loads, air cooled WW with a pure lead nose would be optimum, but for higher speeds up to about 2800 fps make the shank hard as possible.
If shooting real hard lead at temps below about 0 F, without a softnose, one can expect the bullet to disintegrate into powder on impact. I'm most experienced with 30 caliber bullets and tend to speak accordingly. Larger bullets stress the alloy more than small, so one has to expansion test whatever he is loading to be sure the bullets will withstand the impact he is putting on them.
