I've had only one bullet/cartridge/game combination that caused me to say, "no more." I used the 350 Rem Mag with the 200 gr. Hornady SP at 2650 fps to shoot three black bears, but no more. The first one I shot at 30 yards in and out ribs, and found it 20 yards away. There was a small blood trail leading to it. The second one I shot quartering away at 60 yards, and found no blood and no bear. It got into some head high grass in a swamp, and I figured I must have made a bad shot. The third I shot the same as the second. It went about 40 yards, but didn't go into the grass. The only blood I found was a small amount from it's nose. Again, no penetration. Maybe I was pushing that bullet too fast.
I haven't yet tried a bullet/cartridge combo that didn't work on a deer, but maybe I've just been lucky.
Hard to say with the two you didn't recover, who knows. I've shot only deer with that bullet in a 358 Win about 100 fps slower and worked well. I have a bunch of the 200 Core Lokts (SP and RN) and though generally not as accurate, I think they're a little tougher, at least they act like it.
