It's been like 3 editions since I've seen a basilisk in use and I'm unsure exactly how they work, it says the range is 36"-240" does that mean it can't fire at anyone below 36"?
Barrage weapons can fire indirectly. This means they can fire at a target that they do not have line of sight to, as long as the target is beyond their minimum range (if applicable). When firing indirectly, the Ballistic Skill of the firer is not subtracted from the scatter distance; unless a Hit! is rolled on the scatter dice, the blast marker always scatters a full 2D6". If a Barrage weapon has line of sight to its target it can fire directly, even if the target is within its minimum range.