I understand that we're all mostly hunting deer. But I did find an interesting reference about terminal performance. This would suggest that the type of bullet depends more on the class of game animal, and velocity to an extent. A very large heavy animal may require a bullet that does provide maximum penetration to reach deep into the vitals in order to put it down quickly. The particular bullet that I was asking about is a .45-70 bullet. I'm not doubting what has been said, it's just that there's different applications for different animals, whether that happened to be buffalo, moose, bear, muskox, etc...as opposed to deer. To just think about how large a horse is compared to a deer. And handguns are being referred to because of their lower velocities, which the .45-70 also has, especially when fired from some older rifles and when loaded with some powders. Keep in mind that I'm only guessing about the types of animals. Maybe they're called thick skinned game.
Classes of bullet
There are three basic classes of bullet:
those designed for maximum accuracy at varying ranges
those designed to maximize damage to a target by penetrating as deeply as possible
those designed to maximize damage to a target by deforming to control the depth to which the bullet penetrates.
The third class may limit penetration by expanding or fragmenting.......
Flat point
The simplest maximum disruption bullet is one with a wide, flat tip.[citation needed] This increases the effective surface area, as rounded bullets can allow tissues to "flow" around the edges. It also increases drag during flight, which decreases the depth to which the bullet penetrates. Flat point bullets, with fronts of up to 90% of the overall bullet diameter, are usually designed for use against large or dangerous game. They are often made of unusually hard alloys, are longer and heavier than normal for their caliber, and even include exotic materials such as tungsten to increase their sectional density. These bullets are designed to penetrate deeply through muscle and bone, while causing a wound channel of nearly the full diameter of the bullet. These bullets are designed to penetrate deeply enough to reach vital organs from any shooting angle and at a far enough range. One of the common hunting applications of the flat point bullet is large game such as bear hunted with a handgun in a .44 Magnum or larger caliber. The disadvantage of flat point bullets is the reduction in aerodynamic performance; the flat point induces much drag, leading to significantly reduced velocities at long range.
http://en.wikipedia.org/wiki/Terminal_ballistics