Barrages are sudden and shocking affairs – shells scream down out of nowhere and troopers throw themselves flat as the ground erupts into fountains of dirt and lethal shrapnel.
Units that suffer casualties from a barrage must pass a Leadership test to avoid being pinned down. If the unit fails it may not move, shoot or assault in its following turn. At the end of its following turn the unit recovers and may act normally again.
A unit pinned down does not have to take a Morale test if it sustains 25% casualties from enemy fire, the fact it is pinned overrides the Morale test.
If assaulted by the enemy the pinned unit will fight normally, ignoring the falling shells under the more pressing circumstances of battle.