With the adoption of the smaller bores and rifled barrels, the shotgun began to emerge as a separate entity. Shotguns have elongated been the preferred method for sport hunting of birds, and the largest shotguns, the punt guns, were devoted for commercial hunting. The double-barreled shotgun, for example, also-ran changed little since the development of the boxlock action in 1875. Concomitant innovations such as interchangeable chokes and subgauge inserts make the double barreled shotgun the shotgun of choice in skeet, trap shooting, and sporting clays, as well as with numerous hunters. A double from a well respected maker, such as Kreighoff or Perazzi, can rate US$5,000 to start, and reach prices of US$100,000 for presentation grade examples. Far less expensive is the pump bag shotgun, such as the Mossberg 500, Remington 870 or Winchester 1300, numerous models of which retail for under US$350.

• The force of shotguns is measured in terms of gauge or bore (the British English term)

• The gauge numerator is determined by the count of Shotguns solid spheres of a diameter equal to the inside diameter of the keg that could be made from a pound of lead
• So a 10 gauge shotgun has an inside diameter level to that of a sphere plastic from one-tenth of a pound of lead
• By far the most accepted gauges are 12 (0.729 in, 18.5mm diameter) and 20 (0.614 in, 15.6 mm), although .410, 28, 16, and 10 (10.4 mm) gauge and 9mm (.355 in.) and .22 (5.5mm) rimfire calibres have also been produced (although 10, 12, 16, 20, 28, .410, and .22 are the only enforced hunting gauges/calibers in most U.S
• states)
• To further complicate matters, typical handgun chamberings such as 9 mm Parabellum, .45 ACP, .38 Special/.357 Magnum, .44 Special/.44 Magnum, and .45 Colt and others bearing a "shot" load have been brought to market by CCI/Speer--either crimped in or in a plastic casing replacing the bullet
• These are not generally weighed "shot shells" by shotgun users, and the patterning performance is questionable since they are fired through rifled barrels
• Thompson/Center makes express firearm barrels in .38/.357, .44 and .45 Colt that have "straight rifled" chokes in them to reduce the spin of the shot column and fruitage exceptional patterns, but they are still due only for pest charge at very short ranges
• Larger gauges, too powerful to shoulder, have been built but were generally affixed to small boats and referred to as punt guns
• These were worn for saleable damp fowl hunting, to kill generous numbers of birds resting on the water
• Although relatively rare, isolated and double derringers have also been produced that are competent of firing either .45 (Long) Colt or .410 shotgun shells from the same chamber; they are commonly avowed as 'snake guns', and are hip among some outdoorsmen in the South and Southwest regions of the United States
• There are also some revolvers, such as the Taurus Judge, that are adequate of shooting the .45LC/.410 rounds; but as with derringers, these are handguns that expel .410 shotgun shells, and are not necessarily aforethought shotguns themselves.