Cover worsens the firer's Expertise target; defined cover areas block LOS.
How it works
If at least half the unit is in cover the whole unit benefits: Soft +1, Moderate +2, Hard +3 to the firer's required roll, but never worse than 6+. Fire into or out of cover only if within 2" of its edge; targets in the same cover area only within 6". Flamethrowers and tank cannon ignore cover.
If the target of a firing attack is in cover the number the firer needs to roll to hit (its' expertise) is modified as shown below