Some pieces of ordnance are used for laying down a barrage in the same way as mortars (though on a much larger scale). These weapons will have G (for guess) suffixed to their range in the Weapon charts. These weapons do not need line of sight to fire but may have a minimum range. If the Blast marker scatters or is placed so that it is within minimum range, then it misses automatically.
Firing on the move. It is difficult enough calculating where a barrage will fall without its origin point moving around! Ordnance barrage weapons may only be fired when stationary. The vehicle may still pivot unless immobilised, however.
Firing Procedure. When you fire barrage weapons you have to state the target unit and then guess the range to it in inches from the firing unit. Intervening obstacles and terrain do not block the line of fire for these weapons, so you don't need a line of sight to the target in order to shoot at it.
Place the Ordnance Blast marker for the weapon at the distance guessed and then see if it landed on target by rolling the Scatter dice and a D6 together. If you roll a HIT symbol the shot lands at the range guessed. If an arrow symbol is rolled the marker is shifted in the direction indicated by the arrow a number of inches equal to the roll on the D6. Calculate hits on enemy models and remove casualties as for blast weapons (i.e. from beneath the Blast markers).