@1894, that's not the problem mate. High weight retention at the right speed will cause less meat damage that a bullet that fragments. Its speed that's the problem, as high speed and a large frontal area transfers too much energy in the form of shock. Excessive force has been used for the gameweight, hence wrecking the carcass.
An example from the other end of the .30 cal spectrum. If I shoot a red hind with a .30-30 at 100yd with a hard round nose 170gr bullet, the bullet will mushroom and leave a good sized exit, but with only slight peripheral bruising or bloodshot meat. That's because it is hitting the animal at about 1800fps, and the hydraulic shock from the bullet strike is very low.
The .300 Win Mag however, that's hitting the same sized animal at 2800fps. The hydraulic shock - the pressure wave through the animal's body - breaks the tissue and hence the flow of blood through the meat. Watch the slow-mo shots of this happening. Here's a really good example with a .30 cal magnum... slow even the slo-mo down to 0.25x and watch the incredible shock wave through the body.
A well hit meat animal shot with a heavy, super fast bullet at close range will often end up being cut in half and the entire forequarters chucked out. I did exactly that recently with a small red hind hit with the 28 Nosler at ~250m, the bullet exited just
behind the shoulder yet the entire offside shoulder was wrecked, right up through the front of the backstrap, just a pulpy gooey bloodshot mess. The nearside shoulder around the POI looked like it was hit by a truck.