Engine Purge

Use this Stratagem at the start of your Movement
phase if the Devestator Doctrine is active. Until
the start of the next battle round, when resolving
an attack made with a Heavy or Grenade weapon
by an IRON HANDS model from your army, on
an unmodified wound roll of 6 add an additional
1 to the Armour Penetration characteristic of that
weapon fir that attack. You can only use this Stratagem
once per battle.