Once a hit has been scored on a vehicle roll a D6 and add the weapon's Strength characteristic to it. Then compare the total against the vehicle's Armour Value.
If the total is less than the vehicle's Armour Value the shot bounces off.
If the total is equal to the vehicle's Armour Value the shot causes a 'glancing hit'.
If the total is greater than the vehicle's Armour Value the shot scores a penetrating hit.
EXAMPLE: A lascannon shot hits the front of a Space Marine Predator that has an Armour Value of 13. Rolling a D6, the player scores a 4, and adds this to the lascannon's Strength of 9 for an Armour Penetration total of 13. This equals the Armour Value of the Predator and so inflicts a glancing hit.
Further example Armour Values for different vehicles are shown on the chart overleaf.
Ordnance Weapons. Ordnance weapons fire such enormous projectiles that they can smash through armour or hit with such force that the target vehicle's crew are turned to mush. When you roll to penetrate a vehicle's armour with an ordnance weapon you get to roll two dice instead of one and pick the highest result.