Powerful weaponry is quite capable of punching through different types of armour. This is shown by a weapon's Armour Piercing value. Nearly all weapons have an Armour Piercing rating. This is most commonly 6, but potent weapons like bolters and heavy weapons might have values of 5, 4 or even less. Some sample Armour Piercing ratings for different weapons are shown below.
| Weapon | AP |
|---|---|
| Splinter Rifle | 5 |
| Boltgun | 5 |
| Heavy Bolter | 4 |
| Lascannon | 2 |
The lower the rating the better, because it indicates the armour save the weapon can defeat and automatically punch through. So, a bolter with an Armour Piercing rating of 5 automatically pierces armour which has a save of 5 or 6; a lascannon with its Armour Piercing rating of 2 automatically pierces armour which has a save of 2, 3, 4, 5 or 6.
If the weapon's Armour Piercing value is sufficient to punch through armour as described then the target gets no save at all. The armour is ineffective against the shot.
If the weapon's Armour Piercing value is not able to automatically punch through the armour then the target can attempt to save as normal.
EXAMPLE: A bolter has an Armour Piercing value of 5 so Armour saves of 5 or 6 are automatically ignored. Saves of 4+ are taken as normal.