Blast weapons fire shells, missiles or energy bolts that explode on impact, potentially injuring several victims with shock waves and shrapnel. When you fire a blast weapon roll to hit as normal. If the shot misses it has no effect. If it hits place the Blast marker over the target unit to see which models are affected.
Models partially covered are hit on a D6 roll of 4 or more, models completely covered are hit automatically. The defending player has to remove any casualties inflicted from the models directly beneath the Blast marker.
Unscrupulous players may be tempted to use blast weapons to pick off leaders and heavy weapons in an unrealistic fashion. To prevent this the following rule applies. The owner of the target unit can move an incoming Blast marker onto a different part of the target unit providing that:
a) The Blast marker covers the same number of models (or more) in the same unit.
b) The new target is within the firer's range and line of sight.
Diagram: Blast Weapons — a Blast marker template is placed over a target unit. A model fully under the marker is hit automatically ("Hit"), while a model only on the edge of the marker is hit only on a D6 roll of 4+ ("Hit on 4+").
Errata — Chapter Approved: Main Rules Clarifications (v2.0): When repositioning a Blast template on your unit after an opponent has hit it, you may reposition it so that it covers enemy models as long as it still covers at least as many of yours as it did originally.
Errata — Chapter Approved: Main Rules Clarifications (v2.0): When a unit fires multiple Blast templates on the enemy (say a Devastator squad firing four frag missiles), and several missiles hit, place one Blast template and multiply that by the number of hits to determine how many models might be wounded.
Errata — Chapter Approved: Main Rules Clarifications (v2.0): Markers that are placed by a player – whether they use the large or small Blast template – and which do not have to test for scatter may be repositioned.