[quote=@Frizan]
<Snipped quote by Peik>

I'm no expert either, but I assume, with absolutely no prior knowledge, broadhead arrows were made for, indeed, cutting into cloth or leather armor, but in conjunction with the point of the arrow piercing into the actual body of your enemy. So the main point of the arrow was still to dig into its target instead of cutting them up at range.
[/quote]

From what studies I've had, the broadhead was for penetrating the ribcage of large game such as deer.  Having only two blades and more metal involved it had greater weight and could pass between the ribs if it hit on the correct part of the rotation.  If not, it had the mass to punch through the ribs directly.

Armor piercing arrows were narrower with either a diamond like cut or another type with a pronounced point.  Though, some broadheads did have swept back barbs for human targets.  After all, penetrating a ribcage is what they're best at.