The solid copper bullets work differently than your standard lead bullets. The solid copper bullets have less hydrostatic shock than the same weight lead bullet does from the same cartridge. What does this mean? The actual wound channel will be smaller than a lead bullet. The solid copper bullet does not create the massive wound channel like the same weight lead bullet does. The benefit of the copper bullet is penetration. You will 99% of the time get an exit wound with the solid bullet. Lead bullets, no so much. Often times you recover the bullet or fragments of the bullet under the off-hand side of the skin. The lead bullet will expand more and create a larger hydrostatic shock wound channel. I have had numerous customers go away from the Barnes TSX bullets because of this. A lot of these customers go on big time hunts and shoot many animals. From my shooting and hunting experiences, I have seen the same thing. I won't use or recommend the solid bullets, unless you need the penetration, like for dangerous game and such. The solid bullets will expand, but leave a smaller exit wound, which will limit your blood lose on the ground.

So a shot behind the shoulder into the lungs will result in a dead deer. But the hydrostatic shock created is much less than a lead bullet, which allows the deer to run off. Sure, the deer went down somewhere, but maybe not close enough to find with a decent amount of blood trail.

Exactly. To make up for, or get more shock, you reduce the bullet weight and add the speed.

With all due respect, that actually makes no sense. So a larger TSX produces little "hydrostatic shock" but a smaller one blitzing even faster does? I'm not buying it.

A smaller hole may take a few more seconds to kill (and that can mean an extra 50-100 yards of tracking). This either can be no issue or a big issue, depending on where one is hunting.

This is why the OP lost the 2 animals, the bullets likely did not deform as it travelled through the target. Yes the animals almost certainly died from these wounds, but a much lighter TSX pushed as fast as possible is more likely to open up in the animal, leading to greater internal damage and likley quicker expiry.

Shooting a Cape buffalo with a 100 grain solid is not as good as shooting one with a 400 grain solid. Period. Same principle.

Poke a hole in buff's heart with either 100g or a 400g, its gonna die. Period. Same Principle.

Poke a hole in buff's heart with either 100g or a 400g, its gonna die. Period. Same Principle.