Relentless Onslaught

Use this Stratagem in your Shooting phase, when
a Core Infantry unit from your army is selected
to shoot. Until the end of the phase, each time a
model in that unit makes an attack with a Rapid
Fire weapon, an unmodified hit roll of 6 scores
one additional hit.
The Necron soldiery stride forward, tracking their
targets and unleashing volley after volley with
merciless efficiency.