Hellfire Shells

Use this Stratagem in your Shooting phase, when
an ADEPTUS ASTARTES INFANTRY model
from your army shoots with a heavy bolter, a hellstorm heavy bolter, or an executor heavy
bolter. You can make only one attack with that
weapon this phase, but if a hit is scored, the
target suffers d3 mortal wounds and the attack sequence ends. MONSTER units suffer 3 mortal wounds instead of d3.