ENGINE PURGE

Use this Stratagem at the start of your Movement
phase if the Devastator 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 for that attack.
You can only use this Stratagem once per battle.