Frag (n)
After rolling to hit with a weapon using the Explosive or Grenade keywords, roll a (n) dice 4+ test (x) for the strength of the attack. No modifiers or rerolls allowed. Models in the target cube must roll a 3 dice Survive test (x)
The shooter rolls once for the attack and then each model in the cube rolls separately for their Survive test (enemy and friendly models are all affected)
Draw or Survive has more successes: Attack fails to cause any hits
Frag has more successes: The difference in number of successes is the number of hits caused. (refer to Damage and Death on page 20 in the rulebook)
Whatever the results of the attack, all surviving models in the target cube are thrown one cube in a random direction (refer to Scatter on page 28 in the rulebook) and are then pinned.