The wall piece was a type of firearm used during the 18th century by the national and colonial armies of most European countries. Essentially, it was a scaled-up version of the army's standard infantry musket, operating under the same principles, but with a bore of up to one-inch (25.4 mm) calibre. These weapons filled a gap in firepower between the musket and the lightest artillery pieces, such as the swivel gun. Wall pieces were so named because they were designed to be used along the walls of fortifications. They were equipped with a yoke at the point of balance, which tapered into a pivot, which could be inserted into several sockets along the walls, which would absorb the recoil of the piece and also provide a stable gun platform. (In this respect they were much like a scaled-down version of the swivel gun.) Wall pieces could also be mounted on very light carriages for service in the field, usually in support of the larger guns. They were also used on small naval vessels.
This sort of weapon may also be found described as an amusette, especially when deployed in the field.