a cartridge bag of gunpowder was loaded first. a double bag was used with heated shot to prevent leakage of grains of gunpowder as the bag was rammed down the cannon. once the bag was in place, a wad of moistened clay or cloth was rammed down against the bag to shield it from the heated shot, which was loaded next. if the cannon was to be fired at a downward angle, another wet wad was rammed against the ball to prevent it from rolling out.