...All the bullets I have used in hardcast have been commercially made with a BHN of 20 to 22 and in the four cartridges I shoot them out of they zip right on through WHATEVER they come in contact with! Thankfully I have yet to loose a shot critter, so I shouldn't complain about or question the BHN of those bullets....
What's wrong with 2 holes and dead critters?? That's what a hardcast is supposed to do.
It's not a problem, it's a feature!