Breech-loading swivel guns were developed surprisingly early, and were used from 1370 onward. The guns were loaded with mug-shaped chambers, in which gunpowder and projectile had been filled in advance. The chamber was then put in place, blocked with a wedge, and then fired. As the loading was made in advance and separately, breech-loading swivel guns were quick-firing guns for their time. An early description of a breech-loading swivel gun puts the weight of the gun at 118 kg, equipped with three chambers for rotations, each 18 kg in weight, and firing a 280 g lead shot. The guns had a disadvantage: they leaked and lost power around the chambers, but this was compensated by the high rate of fire as multiple chambers could be prepared in advance. Breech-loading swivel gun could fire either