They are fairly hard. I would guess 92-6-2 Hardball alloy, with a Brinell that most people call 16. It's a standard "hard" alloy. I've not shot any animals with that specific bullet, but I have shot some with that specific alloy in 44 cal. As long as they fit your gun and don't lead things up, they would be fine for hunting. Cast flat points aren't designed to expand. The size of the meplat on the bullet coupled with its speed determines the size of the wound channel. They will break bones and exit from nearly any angle, even at moderate velocities.