Artillery was Napoleon's forte. He had come through the ranks as an artillery officer and knew more than most about the deployment and effectiveness of the big guns. It is surprising, then, that he did not make better use of his artillery at Waterloo. Effective use of artillery involved massed fire intended to neutralise whole areas of the enemy position rather than to pick off individual targets. Grand batteries would be used to soften up the enemy line prior to an attack by infantry or cavalry. This was the intention at Waterloo but, since Wellington had perfected the art of deploying behind a reverse slope, the effect of the French artillery was not what it could have been.
It is surprising that Napoleon did not make better use of his artillery at Waterloo
Guns came in huge variety of shapes and sizes, ranging from 4 pdr horse guns up to 24 pdr siege guns. The most common type of ammunition used was round shot. This was a solid iron ball, useful for smashing through walls and other defensive structures. It was also particularly deadly against massed formations of infantry or cavalry. On dry days, the normal range of 700-900 yards would be greatly increased by bouncing the round shot along the ground. Obviously, the shot would not stop when it hit the first man or horse. Canister was also particularly deadly against massed formations; cylindrical cases filled with small iron balls and fired from a range of 200-600 yards with predictable consequences. Common shell was used by howitzers. This was a hollow sphere packed with gunpowder and fused, so as to explode on impact. Common shell was useful for setting fire to targets and firing over obstacles.