Quote Originally Posted by Handel
Listened quite carefully during the last siege - fortress with cannon towers. The sounds wes definitely of ballistas, not cannons. what the towers really shot I don't know - I am quite confused now. What the towers shot looked as firebolts wich set the siege tower in fire.
The towers appear to get extra ammo while there is siege equipment in range, at least in the higher end settlements. You'll see only regular shots coming out when it is only troops but if it's a siege tower/ram or an artillery piece that wondered too close, you'll see the regular ammo fired plus a flaming shot.