Unyielding Chitin

Use this Stratagem in your Charge phase or your opponent’s Shooting phase, when a TYRANID
PRIME or TYRANID WARRIORS unit from
your army is chosen as the target for an
attack made with a ranged weapon. Until the end
of that phase, when resolving an attack made
with a ranged weapon against that unit, reduce
the Damage characteristic of that weapon by 1, to
a minimum of 1, for that attack.