what is an armor piercing bullet?

[sarisataka]

11. It depends on the composition of the bullet

is a 7.62 full metal jacket bullet armor piercing? or perhaps a .40 caliber hollow point? or a 30-06? a 30-30? what about the dirty hairy .44 mag round, is that armor piercing?

all of those are "maybe" except for the hollow point; it is very difficult to design a HP round that is also AP.

To be an armor piercing bullet it needs to have a penetrator at its core made of a hard material such as tungsten, hardened steel or other such material. It is a matter of a design feature that specifically increases the capability of the bullet to penetrate armor.

It is possible to penetrate armor with non-armor piercing bullets. Large caliber rounds can smash through hard substances without being an armor piercing bullet.