Quote Originally Posted by OPFOR View Post
This is only partly true. Actual Armor Piercing ammunition (where they are most common, in military rifle calibers) have the same exact shape as non-AP rounds. They are different in their internal construction, because the materials do, in fact, affect their penetrating capabilities.

ETA: Additionally, velocity has quite a bit to do with whether a handgun round will penetrate soft body armor, as do many other factors (including bullet materials) to greater and lesser degrees.
inside the round is the armor piercing part, so it's only the same shape for reliability for feeding.