A bullet can certainly fail and the critter is still dead. A dead animal is not necessarily the outcome of good bullet performance. I shot a black bear with my 9.3X300 WM at about 60 mtrs just peeking over a grassy knoll at me. I aimed just below the chin and touched off at him. The bullet actually just touched the bottom of the lower jaw (didn't even break the jaw just cut a tiny trough in the jawbone) and then proceeded to enter the chest in excess of 20 different pieces. The bear was absolutely stone dead, but the bullet was a total and abysmal failure. The bullet was a 270 gn Speer HC at right around 3000 fps. There is not a soul on this site that would call this performance anything but an absolute and total bullet failure..........however he is still the biggest blackie I have killed to date.......Went to Matrix bullets after this with this cartridge and took a nice grizzly and wolf thereafter.
OP...I have used the 270 gn TSX bullet on several trips to Africa with my 375 H&H and very highly recommend them. I have shot everything from duiker to leopard to lion and hippo with this bullet and have been very pleased with it's overall performance. I have recovered many of these bullets and the performance is pretty predictable......if very heavy bone is hit they will shed some or all of the petals, but on lighter bone and soft tissue they come out picture perfect every time.
I talked with two very distraught buffalo hunters at the airport in Lusaka Zambia who were using GMX bullets in their 458 Lotts and one guy lost 2 buffalo and the other lost his as well. Both professed to be very good shots with their rifles and were completely bewildered as to why they were empty handed and empty pocketed. Their PH was the same guy I was using and we discussed their losses at length and the only conclusion was total bullet failure. He confirmed that all hits were exactly where they were supposed to be, but the buffalo ran off and never died, or at least on that day or the next......I have steered clear of GMX bullets for this reason and can give no personal experiences, thank God, for I fear they would not be good ones.
Africa is not the place to do bullet testing if one is paying for the animals he hits. I tend to do mine on black bears..........Regardless one wants to arrive with a rifle and load that gives 100% confidence and has proven itself to be a top performer on the size of game being pursued. This can be difficult and that is where forums like this can be helpful because it is difficult to get all that experience oneself. Whereas many on this forum have taken many varied animals with many varied cartridges and bullets, and to call upon their experience is priceless.
My son has taken upward of 3 dozen animals with his 375 Ruger using 260 gn Accubonds. He used this rifle and load on his first solo trip to Africa and shot everything with it right up to and including 2 eland, as well as moose and grizzly at home. He is very impressed with the performance of this bullet cartridge combo and made a couple 400 mtr shots in Africa with it as well. Apparently his PH was equally impressed with the performance as well as his ability. This is another bullet I would highly recommend on any game up to, but not including the nasties. I would have no qualms whatsoever of taking on any animal, elephant included with my 270 TSX load. One of the reasons I use this rifle and load in Africa a lot........did I mention how much I hate elephants.........
Just my experiences you can take them for what they are worth, or what you paid for them.....