A punt gun is a type of extremely large shotgun used in the 19th and early 20th centuries for shooting large numbers of waterfowl for commercial harvesting operations. These weapons are characteristically too large for an individual to fire from the shoulder or often carry alone, but unlike artillery pieces, punt guns are able to be aimed and fired by a single person from a mount. In this case, the mount is typically a small watercraft. Many early models appear similar to over-sized versions of shoulder weapons of the time with full-length wooden stocks with a normal-sized shoulder stock. Most later variations do away with the full-length stock — especially more modern models — and have mounting hardware fixed to the gun to allow them to be fitted to a pintle.

A shotgun is a long-barreled firearm designed to shoot a straight-walled cartridge known as a shotshell, which discharges numerous small spherical projectiles called shot, or a single solid projectile called a slug. Shotguns are most commonly used as smoothbore firearms, meaning that their gun barrels have no rifling on the inner wall, but rifled barrels for shooting sabot slugs are also available.