Hola Alvaro!
Wasn't me who used a GPA on a black bear!
Eileen and I have recovered a few monolithics--along with one Fail Safe--that have lost all their petals. Some have been designed that way, like the 40-grain Cutting Edge Raptor that Eileen used at 4300 fps from a .22-250 to crumple a pronghorn maybe 5 years ago. The antelope was quartering toward Eileen at about 150 yards, so she put it just inside the near shoulder, and the doe dropped instantly. Found out why during butchering: The bullet had cracked the bottom of the spine and the far shoulder blade, before ending up under the skin. I can't remember what the remaining shank weighed (Eileen has it in her collection somewhere) but Raptors are designed to lose their petals, and it wasn't much more than 50% of its original weight, maybe 25 grain--yet it penetrated around 18 inches.
The others have all been bullets that tend to retain all their petals, One was an original Barnes X-Bullet, the hollow-point, without shank grooves, a 120-grain from a 6.5x55 that I used on a big axis deer. The range was around 130 yards, and the buck was quartering toward me so I shot it through the shoulder. It ran 35-40 yards, on three legs, before going down. The bullet had hit the big shoulder joint, ending up under the flank skin on the other side, losing all its petals and retaining 77.5% of its weight--but even without the petals the front end was "mushroomed," measuring .41 inches across.
Eileen shot a Namibian gemsbok bull as it almost faced her at 200 yards, using a .30-06. The 165-grain Fail Safe cut a carotid artery and crunched the bottom of the spine, so the bull dropped right there. The bullet ended up under the rump skin with all the petals gone, retaineing 80% of its weight--but again the front end was mushroomed (riveted?) a little, and oddly enough also .41 across, even though the caliber was larger than the 6.5 X used on my axis deer.
Eileen's last elk was taken with a 130-grain TTSX from her custom .308 Winchester at about 250 yards. Again, the BIG cow was quartering on, and staggered 20-25 yards toward us before falling. The bullet broke the shoulder slightly above the big joint, and was found under the rib-skin on the opposite side without any petals--though one was found a couple inches from the bullet. Retained weight was 62%, and the front end was also mushroomed a little, to .40 at the widest point.
We have a pretty good collection of recovered monolithic bullets, mostly Barnes because they've been around longest, but also E-Tips and GMX's. I do suspect that we find more than some other hunters because we personally butcher all the animals that go into our freezers, and make it a point to look for bullets--rather than taking the animals to a meatcutter. In fact a few years ago we recovered two monos in a row, both 100-grain TTSX's from Eileen's NULA .257 Roberts, the first from a quartering-away cow elk, and the second from a directly facing pronghorn doe.
The Berger bullets we've used have punched the typical very small hole at the entrance--sometimes so tiny you have to part the hair to find it--which ruins far less meat any monolithic we've used. Then they violently expand inside the animal, sometimes so much they don't exit, though even when they do the meat damage is minimal because they're going VERY slowly by then. Have talked to a very few people who had Bergers break up at the entrance when they hot big bone, ruining some meat, but so far we haven't encountered that in the dozens used to take big game from pronghorns to a red stag about the body size of a 3-year-old bull elk.
