Once the marker has been placed, roll for scatter using a scatter dice and an artillery dice. Assuming that you didn't roll a misfire on the artillery dice, it's now time to find out whether or not your shot was on target.
If a hit is rolled on the scatter dice, the shot has landed on target. In this case, we ignore the number shown on the artillery dice – the hit is all we need. If an arrow is rolled, the shot has missed its original target and scatters off elsewhere. Move the marker a distance in inches equal to the result of the artillery dice divided by half, in the direction shown on the scatter dice.
Using your tape measure, extend a 'shot' line from the cannon's barrel all the way to the marker – this is the direction the cannonball travels straight forward. If you roll a misfire, something goes wrong when the cannon fires. You'll now need to roll on the Black Powder War Machine Misfire chart to discover the seriousness of the situation. Regardless of the result rolled, the cannon does not shoot this turn.