Here is a quick concept of the Crayling infantry in Steam Knight. Not all of them are equipped with the PB-244 Portable Cannonade (or 'Boomstick' in trencher terms) however most squads do have at least four to cover advances and deal with heavy targets, such as Ogres or war machines like seige towers and battering rams.
The Boomstick is a primitive scattergun - nowhere near as sophisticated as a shotgun - but manages to reflect the qualities of the cray themselves - light, efficient, and adaptible. The PB-244 is capable of firing anything small enough to be shoved in the barrel with a load of powder - rocks, nails, chain links, you name it. However they are also capable of firing specially-made explosive rounds for hard targets. Most cray infantry with the PB-244 have 2 of these shells issued at time of enlistment but are encouraged to seek out more, of the means to manufacture more, be it from enemy supply caches or fallen comrades.