I suggest the Accubond. They are essentially the same bullet as the NBT, but have the core bonded to the jacket so they penetrate better. Since they are otherwise identical to like-weight BT's, they have the same ballistics-supposedly.

Otherwise, try a Nosler Partition bullet! In almost 50 years of using these, I have only found 2 of them inside the animal. And after these had busted up a lot of bone. All the rest went through, and let blood out both sides of the critter! Not only that, but the front half usually actually blows up in the middle of an animal, doing MAX damage to the machinery in there.....