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 and private sport. Punt guns were usually custom-designed and so varied widely, but could have bore diameters exceeding 2 inches (51 mm) and fire over a pound (≈ 0.45 kg) of shot at a time. A single shot could kill over 50 waterfowl resting on the water's surface. They were too big to hold and the recoil so large that they were mounted directly on the punts used for hunting, hence their name. Hunters would maneuver their punts quietly into line and range of the flock using poles or oars to avoid startling them. Generally the gun was fixed to the punt; thus the hunter would maneuver the entire boat in order to aim the gun. The guns were sufficiently powerful, and the punts themselves sufficiently small, that firing the gun often propelled the punt backwards several inches or more. To improve efficiency, hunters could work in fleets of up to around ten punts.
In the United States, this practice depleted stocks of wild waterfowl and by the 1860s most states had banned the practice. The Lacey Act of 1900 banned the transport of wild game across state lines, and the practice of market hunting was outlawed by a series of federal laws in 1918.
In the United Kingdom, a 1995 survey[which?] showed fewer than 50 active punt guns still in use. UK law limits punt guns to a bore diameter of 1.75 inches (44 mm) (1 1/8 pounder). Since Queen Victoria’s Diamond Jubilee in 1897 there has been a punt gun salute every Coronation and Jubilee over Cowbit Wash in Cowbit, Lincolnshire, England.
The film Tremors 4: The Legend Begins featured a punt gun used in combat. This punt gun was custom-built for the film and was 8 feet 4 inches (2.54 m) long, weighed 94 pounds (43 kg), and had a 2-inch-diameter (51 mm) bore (classified as "A" gauge by the Gun Barrel Proof Act of 1868 in Schedule B).
Desmond Bagley's 1973 thriller The Tightrope Men features a percussion-fired punt gun.