The culverin, also known as a hand bombard, consists of a simple smoothbore tube, sealed at one end except for a small hole used to ignite a gunpowder charge.

A wooden stock partially encases the barrel, allowing the wielder to hold it under his arm with relative ease when carrying it. Firing a culverin without support (such as a wall, a window, or a stand) imparts a –4 penalty on the attack rolls, and the wielder is knocked prone. A culverin uses 4 doses of black powder and grapeshot. Note that these statistics simulate only the original, hand-held culverins—their larger descendants are considered cannons and are dealt with in the section on siege weapons.