A reader was doing some research on 19th-century firearms, and wrote to ask me why so-called "market hunting" had been banned in the USA in the latter part of that century. The reason was that so many waterfowl and migratory birds were being slaughtered for the "market" by commercial hunters that they had become endangered. The tool of choice for these hunters was the so-called "punt gun".
The history of such guns starts in the 19th century, when the rise in demand for meat in the marketplace led to mass-hunting of waterfowl. Also, the best women's fashions at that time featured feathered hats and feather trimmed dresses and therefore there was a large demand for feathers as well. To meet these demands, professional hunters began to custom-build larger caliber weapons for the task. The punt gun emerged during this period as a commercial way to hunt waterfowl. A punt gun is essentially a large caliber shotgun. Since they have huge barrel diameters (around 2 inches or 50 mm.), they are capable of firing over 1 pound (approx. 0.5 kg.) of shotgun pellets at a time.
Since such a weapon cannot be really held at the shoulder by normal human beings because of the huge weight and immense recoil, they were often fixed to the boats used for hunting. These boats were called punts (a flat-bottomed boat with a square bow designed for shallow water usage) and designed to maneuver around shallow swamps and marshes where water birds would generally feed. This practice of attaching the gun to the punt is what gave the punt gun its name. The hunter would simply mount the punt gun facing forward and maneuver the boat to point to the whole flock of birds without startling them. If multiple hunters were present, they would all move their boats in a parallel line facing the flock of birds. Then, at a given signal, the punt guns would all open fire simultaneously. The recoil of a punt gun was so much that it would often push the punt backwards by several inches.
Since the punt guns generally fired a large amount of shotgun pellets, one of these could easily account for something like 50 birds with just one trigger pull. To increase their hunting efficiency, groups of professional hunters would often maneuver 8-10 punts into position and fire at a flock simultaneously, accounting for the entire flock at one time. In fact, punt guns were so successful in hunting that they depleted wild bird populations and were eventually banned in many US states by the 1860s. Later on, the US federal government passed a law in 1918 banning the practice of market hunting completely, as well as the fashion feather trade by 1920. Hence, the use of punt guns in the US plummeted soon after. There are still a few hunters in the UK using punt guns in the 21st century, but they are limited by law to a barrel diameter of 44 mm. and max. shot weight of 1.125 pounds.
There's more at the link, and in this Wikipedia article.
Here are two videos showing the late shotgun guru, Tom Knapp, and a colleague demonstrating two punt guns. Imagine that the targets were instead a closely-packed flock of birds, and you can understand how deadly punt guns were to wildlife, and why they were banned.
Not your average shotgun, that!