Round ball and round nosed bullets slip through tissue, where high speed bullets, and flat nosed bullets, or balls that flatten out as they enter flesh, cut a huge hole through the flesh, causing much hemorrhaging, tissue distruction due to hydro static shock, and a huge shock to the nervous system, which can often render the animal unconscious, so it bleeds to death where it was hit. The high speed bullets, that are so much smaller in diameter than our RB, kill with the hydrostatic shock WAVE that follows the base of the bullet into the wound channel. The actual hole that burned into the meat may be less than 1/4", but the Hydrostatic shock wound can actually be several inches in diameter, cause far more blood loss, and damage to nerves further away from the wound channel than any slow moving large bullet, or RB can ever expect to do. The flat nosed bullets, and our soft Round Lead Bullet kill because they present a flatten nose to the wound, making a much bigger wound channel, but also creaating a second shock wave, the one off the base of the ball or bullet, and now a second wave off the flat nose, or flatten front of the RB. That is why a round ball seems to be so effective shot into thin-skinned animals, like deer, or even something as small as a rabbit. Remember that flattening is occurring in the body of the animal, so that the transformation of the shape of the RB causes other releases of energy that produce waves of pressure to surrounding flesh and tissue of organs. The RB acts, in effect, like a modern hollow point bullet, only at much lower velocities. The RB is not the projectile of choice for shooting large game animals, with thick skins, and deep bodies. There a bullet makes more sense, and Elmer Keith proved that even a slow moving pistol bullet, with a flat nose, will effectively kill large bear, moose, caribou, and elk. His semi-wadcutter designs are still copied today.
You don't have to skin out or gut a dead animal to see how these things work. If you shoot at paper, a round ball and a round nosed bullet leave a hole with a small center removed altogether, but with fracture lines radiating from that hole. These were made as the round nose stretched then broke and slipped through the paper. A wad cutter leaves a cut round hols, with very little fracture lines around the edge. A faster, semi-wadcutter bullet goes through that same paper like a paper punch, leaving almost no fracture lines around the clean edge. A jacketed rifle bullet with a round nose leaves a similar hole in paper as a round nose lead bullet, or a round ball. A jacketed hollow point leaves a hole with ragged edges, but the small hole in the middle is the diameter of the circumference of the hollow point. A soft point bullet just leaves a ragged edged hole. Only the caliber tells you that you are looking at a rifle bullet hole. You can separate rifle from pistol holes by examining the back of the targets. The rifle bullets will fray more of the paper and drive it ahead and to the side of the bullet as the bullet penetrates the paper. You have to manually push the paper back together to see how much paper is left. With the spitzer shapes, the very small point leaves the smallest actual hole through the paper.