Artillery Ammunition in the Middle Ages

These were hand cut by masons to approximate the diameter of the barrel. The introduction of cast iron cannonballs greatly increased impact power by standardizing size and weight and more snugly fitting the barrel. In addition, iron balls were sometimes retrievable where stone balls were destroyed on impact. And yet, while iron cannonballs are referenced as early as 1341, stone balls were preferred much longer because they were cheaper and their raw material far more plentiful. It took discovery of new deposits of iron and better mining techniques that allowed for deeper delving after ore to bring down the cost of iron ammunition.

A stone cannonball was also lighter, and so required less expensive black powder to heave it at the enemy. On the other hand, hand-cut stone balls inevitably varied in size and weight, and some fit a given barrel better than others. A bad fit resulted in wasted powder and reduced projectile force, as propulsive gasses escaped past the ball instead of pushing it from behind. This led to wide variation in the distance and accuracy of successive shots. In the 14th century, one cannoneer who hit the same target three times in succession was compelled to make a penitential pilgrimage, because observers could not conceive that this feat could have been accomplished without daemonic aid. In consequence, siege cannon-and these were by far the most common type of early guns-had to be hauled close to the targeted city or castle wall, because with point-blank shooting even imperfect guns did capable work of transforming the chemical energy of gunpowder to propellent force, as stone balls hurled at great speed cracked and broke opposing stone on impact.