Blast

Each time you gather attack dice for a [BLAST] weapon, add one additional attack dice for every five models that were in the target unit in the Select Targets step (rounding down). If this ability takes the form [BLAST X], each time you gather attack dice for such a weapon, add X additional attack dice for every five models that were in the target unit in the Select Targets step (rounding down) instead.  Example: If a [BLAST 2] weapon with an A characteristic of 3 targets a unit containing 12 models, you would gather four additional attack dice for that weapon (for a total of seven for that weapon).