Some attacks can penetrate armour with an ease that belies their meagre strength.
Armour PiercingURL Copied!
Wounds caused in close combat by a model with this special rule (or who is attacking with a weapon that has this special rule) inflict a further -1 armour save modifier, in addition to those for Strength.
For example, a Strength 4 model with the Armour Piercing special rule would inflict a -2 armour save modifier when striking in close combat, rather than the usual -1.
If a model has a weapon with the Armour Piercing rule, only attacks made or shots fired with the weapon are Armour Piercing.