I feel like blunt damage would have made more sense for MCH.

[Ephier]

Saying it penetrates armor is not good enough, that's a very vague definition as anything is 'piercing' if you push it hard enough. If you threw a golf ball hard enough you'll give someone a golf ball shaped hole in their body instead of a bruise, that doesn't make it 'piercing' any more than a bullet.

The definition is not vague.

pierce
pɪəs/Submit
verb
1.
(of a sharp pointed object) go into or through (something).

By definition, if the bullet (whether round, pointy, stuffed animal, piece of toast) is going fast enough to GO INTO the object, it is piercing. Your reference to the golf ball is piercing if it is travelling at a fast enough speed.

Even then something sharp is truly "round" at the tip on a microscopic scale. it is impossible to make something into a truly perfect point.