This spell permits an indirect fire siege engine to bombard its targets with greater accuracy, delivering more Damage. The siege weapon receives a +1 enhancement bonus per four caster levels (maximum +5) on targeting rolls and Damage rolls. If used on a direct fire siege weapon, this spell gives a weapon a +1 enhancement bonus per four caster levels (maximum +5) on attack and Damage rolls. An enhancement bonus does not stack with a masterwork weapon's +1 bonus on attack rolls. This bonus does not allow a weapon to bypass Damage reduction aside from magic.