Playing as Venice last night a French army besieged Dijon. I had two units of Pavise Crossbowmen (120 in total). The siegers had one catapult unit (20 men, 2 catapults). The first 10-15 mins of the battle was spent in an artillary barrage by the catapults, and during that time my Pavise crossbowmen fired at them and no-one else. End result: Crossbowmen had spent all their ammunition (all 120 of them) and there are still 3 artillery crew left of the 20. Seemed a bit unfair to me.