Good morning Andrew.
We have a rule for guns as follows:- If the battery is at sea level it can fire at the usual distances as fir ships until the ship is within musket range on the ruler. If the guns are on cliff tops they get extra range out to sea up to one and a half rulers distance, but over a ruler they only have half effect rounded up. So for instance a battery with say five A's at long range at extra long would only have three A's. Once a ship is at chain shot range, the guns cannot depress to hit.

For overshoots, if another ship is within chain shot range and directly in line behind the one fired at, any misses ie 0 chits are redrawn as A chits to see if the ball hit the non targeted ship.

Rob.