In a major offensive the attacker will often attempt to soften up his target with a heavy bombardment before launching his attack. The barrage could come from artillery units far in the rear, close support vehicles like Griffons and Whirlwinds, or from orbital barrages and air strikes. All races and armies have their own forms of artillery support and aircraft, be they Tyranid Biovores and Dactylis, Eldar Night Spinners, Chaos artillery, Ork Fighta-bommerz, or whatever.
A Preliminary Bombardment is unlikely to cause massive damage to a well dug in force, but it will make the enemy troopers keep their heads down and some of them will be so dazed that they only react slowly to the assault which follows. The huge ground-shaking explosions of the bombardment can also help clear the way for an attack by destroying fixed defences like razorwire and tank traps.
Roll a D6 for each enemy infantry, bike or cavalry unit and each section of razorwire or tank traps on the tabletop. On a roll of 6 the unit or obstacle is hit. A squad takes 1D6 hits from the shelling, causing 1 wound each (make armour saves as normal), and must roll a Leadership test or be pinned in their first turn – see the barrage section of the rules for details. Troops which start the game in reserve cannot be hit by a Preliminary Bombardment.
A section of razorwire or tank traps is automatically destroyed by being hit, remove it from play.
Vehicles and bunkers are not affected by a Preliminary Bombardment, (long range shelling lacks the accuracy to hit specific targets), but you should still roll for troops inside them. (Some of the troops may have been caught in the open whilst running for the cover of their vehicles, or they may refuse to dismount from their armoured carriers for fear of more shelling.)