In each friendly Shooting phase, even when engaged in close combat, the Doomwheel unleashes three bolts of warp lightning. Sometimes this is not desirable and so the Warlock Engineer may choose to take a Leadership test in an attempt to stop the Doomwheel from firing. If the test is failed, the machine fires as normal.

Each warp lightning bolt has an 18" range and will strike the nearest unit (friend or foe), regardless of terrain or line of sight. Roll for each bolt separately, measuring from the Doomwheel's base. If the closest unit dies from the first bolt, the second bolt hits the next closest unit in range, and so on. If two targets are equidistant, the owning player may choose which unit is struck. The Zzzzap bolts are Warpstone Weapon.

To work out how powerful the warp lightning is, roll an artillery dice. If you roll a number (2, 4, 6, 8,10) then this is the Strength of all the bolts for this turn. Each unsaved wound is multiplied to D6 wounds. If you roll a misfire result something has gone awry. No more shots are fired this turn and you must roll immediately on the Doomwheel Misfire chart.