From Age of Sigmar - Lexicanum
Cannons are war machines created and used by Ironweld Arsenal armies. These lavished weapons when well-build can last for centuries.
It consists of a cannon set on broad wheels. Engineers can inscribe Runes of Accuracy into the cannon shells to guide them to their target.
To build an Cannon Gun it requires an expert Cogsmith with a specific set of skills, which ends up carrying their pride.
Three Duardin crew this war machine and if it needed they can protect themselves with their tools.