Monster Bombards have the following profile and rules:
Monster Bombards may re-roll the distance bounced by the cannon ball and failed rolls To Wound. If a Misfire is rolled, add -1 to the result on the Blackpowder Misfire Chart.
Source: Warhammer Armies Project: Unofficial 9th Edition (v2.2)
Monster Bombards have the following profile and rules:
Monster Bombards may re-roll the distance bounced by the cannon ball and failed rolls To Wound. If a Misfire is rolled, add -1 to the result on the Blackpowder Misfire Chart.