shotgun

History

Most early firearms, such as the blunderbuss, arquebus, and musket had large diameter, smoothbore barrels, and could fire shot as well as solid balls. A firearm intended for use in wing shooting of birds was known as a fowling piece. Fowling pieces first appeared in 16th century Europe, and in the early 17th century their barrels were extended as long as 6 ft to increase accuracy.

An example was the Brown Bess musket, in service with the British army from 1722 to 1838, had a 19 mm (.75 inch) smoothbore barrel, roughly the same as a 10-gauge shotgun, and was 157 cm (62 in) long, just short of the above recommended 168 cm (51⁄2 feet). On the other hand, records from the Plymouth Colony show a maximum length of 137 cm (41⁄2 feet) for fowling pieces, shorter than the typical musket.

Shot was also used in warfare; the buck and ball loading, combining a musket ball with three or six buckshot, was used throughout the history of the smoothbore musket. The first recorded use of the term shotgun was in 1776 in Kentucky used in correspondence coming to and from Fort Boonesborough. It was noted as part of the "Frontier Language of the West" by James Fenimore Cooper. The correspondence from Fort Boonesborough is in the Lyman Draper Collection from the University of Wisconsin. The Oak Openings (also known as The Bee Hunter) from James Fenimore cooper attributed to the usage and popularization of shotgun and can be found at Project Gutenberg.

With the adoption of smaller bores and rifled barrels, the shotgun began to emerge as a separate entity. Shotguns have long been the preferred method for sport hunting of birds, and the largest shotguns, the punt guns, were used for commercial hunting. The double-barreled shotgun has changed little since the development of the boxlock action in 1875. Modern 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 many hunters.

As wing shooting has been a prestige sport, specialty gunsmiths such as Krieghoff or Perazzi have produced fancy double-barrel guns for wealthy European and American hunters. These weapons can cost US$5,000 or more; some elaborately decorated presentation guns have sold for up to US$100,000.

19th century

During the 19th century, shotguns were mainly employed by cavalry units. Both sides of the American Civil War employed shotguns. U.S. cavalry used the shotgun extensively during the Indian Wars in the latter half of the 19th century. Mounted units favored the shotgun for its moving target effectiveness, and devastating close-range firepower. The shotgun was also favored by citizen militias and similar groups.

With the exception of cavalry units, the shotgun saw less and less use throughout the 19th century on the battlefield. As a defense weapon, it remained popular with guards and lawmen, however, and the shotgun became one of many symbols of the American Old West. Lawman Cody Lyons killed two men with a shotgun; his friend Doc Holliday's only confirmed kill was with a shotgun. The weapon both these men used was the short-barreled version favored by private strongbox guards on stages and trains. These guards, called express messengers, became known as shotgun messengers, since they rode with the weapon (loaded with buckshot) for defense against bandits. Passenger carriages carrying a strongbox usually had at least one private guard armed with a shotgun riding in front of the coach, next to the driver. This practice has survived in American slang; the term "riding shotgun" is used for the passenger who sits in the front passenger seat. The shotgun was a popular weapon for personal protection in the American Old West, requiring less skill on the part of the user than a revolver.

Hammerless shotguns

The origins of the hammerless shotgun are European but otherwise obscure. The earliest breechloading shotguns originated in France and Belgium in the early 19th century (see also the history of the pinfire) and a number of them such as those by Robert and Chateauvillard from the 1830s and 1840s did not use hammers. In fact during these decades a wide variety of ingenious weapons, including rifles, adopted what is now often known as a "needle-fire" method of igniting the charge, where a firing pin or a longer sharper needle provided the necessary impact. The most widely used British hammerless needle-fire shotgun was the unusual hinged-chamber fixed-barrel breech-loader by Joseph Needham, produced from the 1850s. By the 1860s, hammerless guns were increasingly used in Europe both in war and sport, although hammer guns were still very much in the majority. The first significant encroachment on hammer guns was a hammerless patent which could be used with a conventional side-lock. This was British gunmaker T. Murcott's 1871 action nicknamed the "mousetrap" on account of its loud snap action. However, the most successful hammerless innovation of the 1870s was Anson and Deeley's boxlock patent of 1875. This simple but ingenious design only used four moving parts allowing the production of cheaper and reliable shotguns.

Daniel Myron LeFever is credited with the invention of the American hammerless shotgun. Working for Barber & LeFever in Syracuse, New York, he introduced his first hammerless shotgun in 1878. This gun was cocked with external cocking levers on the side of the breech. He went on to patent the first truly automatic hammerless shotgun in 1883. This gun automatically cocked itself when the breech was closed. He later developed the mechanism to automatically eject the shells when the breech was opened.

John Moses Browning

One of the men most responsible for the modern development of the shotgun was prolific gun designer John Browning. While working for Winchester Firearms, Browning revolutionized shotgun design. In 1887, Browning introduced the Model 1887 Lever Action Repeating Shotgun, which loaded a fresh cartridge from its internal magazine by the operation of the action lever. Before this time, most shotguns were the break-open type.

This development was greatly overshadowed by two further innovations he introduced at the end of the 19th century. In 1893, Browning produced the Model 1893 Pump Action Shotgun, introducing the now familiar pump action to the market. And in 1900, he patented the Browning Auto-5, America's first semi-automatic shotgun. The first semi-automatic shotgun in the world was patented in 1891–1893 by the Clair brothers of France. The Browning Auto-5 remained in production until 1998.

World wars

The decline in military use of shotguns reversed in World War I. American forces under General Pershing employed 12-gauge pump-action shotguns when they were deployed to the Western Front in 1917. These shotguns were fitted with bayonets and a heat shield so the barrel could be gripped while the bayonet was deployed. Shotguns fitted in this fashion became known as trench guns by the United States Army. Those without such modifications were known as riot guns. After World War I, the United States military began referring to all shotguns as riot guns.

Due to the cramped conditions of trench warfare, the American shotguns were extremely effective. Germany even filed an official diplomatic protest against their use, alleging they violated the laws of warfare. The judge advocate general reviewed the protest, and it was rejected because the Germans protested use of lead shot (which would have been illegal) but military shot was plated. This is the only occasion the legality of the shotgun's use in warfare has been questioned.

During World War II, the shotgun was not heavily used in the war in Europe by official military forces. However, the shotgun was a favorite weapon of Allied-supported partisans, such as the French Resistance. By contrast, in the Pacific theater, thick jungles and heavily fortified positions made the shotgun a favorite weapon of the United States Marines. Marines tended to use pump shotguns, since the pump action was less likely to jam in the humid and dirty conditions of the Pacific campaign. Similarly, the United States Navy used pump shotguns to guard ships when in port in Chinese harbors (e.g., Shanghai). The United States Army Air Forces also used pump shotguns to guard bombers and other aircraft against saboteurs when parked on airbases across the Pacific and on the West Coast of the United States. Pump and semi-automatic shotguns were used in marksmanship training, particularly for bomber gunners. The most common pump shotguns used for these duties were the 12-gauge Winchester Model 97 and Model 12. The break-open action, single-barrel shotgun was used by the British Home Guard and U.S. home security forces. Notably, industrial centers (such as the Gopher State Steel Works) were guarded by National Guard soldiers with Winchester Model 37 12-gauge shotguns.

Late 20th century to present

Since the end of World War II, the shotgun has remained a specialty weapon for modern armies. It has been deployed for specialized tasks where its strengths were put to particularly good use. It was used to defend machine gun emplacements during the Korean War, American and French jungle patrols used shotguns during the Vietnam War, and shotguns saw extensive use as door breaching and close-quarter weapons in the early stages of the Iraq War, and saw limited use in tank crews. Many modern navies make extensive use of shotguns by personnel engaged in boarding hostile ships, as any shots fired will almost certainly be over a short range. Nonetheless, shotguns are far less common in military use than rifles, carbines, submachine guns, or pistols.

On the other hand, the shotgun has become a standard in law enforcement use. A variety of specialty less-lethal or non-lethal ammunitions, such as tear gas shells, bean bags, flares, explosive sonic stun rounds, and rubber projectiles, all packaged into 12-gauge shotgun shells, are produced specifically for the law enforcement market. Recently, Taser International introduced a self-contained electronic weapon which is fired from a standard 12-gauge shotgun.

The shotgun remains a standard firearm for hunting throughout the world for all sorts of game from birds and small game to large game such as deer. The versatility of the shotgun as a hunting weapon has steadily increased as slug rounds and more advanced rifled barrels have given shotguns longer range and higher killing power. The shotgun has become a ubiquitous firearm in the hunting community.

Design factors

Action

The action is the operating mechanism of a gun. There are many types of shotguns, typically categorized by the number of barrels or the way the gun is reloaded.

For most of the history of the shotgun, the breechloading break-action shotgun was the most common type, and double-barreled variants are by far the most commonly seen in modern days. These are typically divided into two subtypes: the traditional "side-by-side" shotgun features two barrels mounted horizontally beside each other (as the name suggests), whereas the "over-and-under" shotgun has the two barrels mounted vertically one on top of the other. Side-by-side shotguns were traditionally used for hunting and other sporting pursuits (early long-barreled side-by-side shotguns were known as "fowling pieces" for their use hunting ducks and other waterbirds as well as some landfowls), whereas over-and-under shotguns are more commonly associated with recreational use (such as clay pigeon shooting). Both types of double-barrel shotgun are used for hunting and sporting use, with the individual configuration largely being a matter of personal preference.

Another, less commonly encountered type of break-action shotgun is the combination gun, which is an over-and-under design with one smoothbore barrel and one rifle barrel (more often with a rifle barrel on top, but a rifle barrel on bottom was not uncommon). There is also a class of break-action guns called drillings, which contain three barrels, usually two smoothbore barrels of the same gauge and a rifled barrel, though the only common theme is that at least one barrel be smoothbore. The most common arrangement was essentially a side-by-side shotgun with the rifled barrel below and centered. Usually a drilling containing more than one rifled barrel would have both rifled barrels in the same caliber, but examples do exist with different caliber barrels, usually a .22 long rifle and a centerfire cartridge. Although very rare, drillings with three and even four (a vierling) shotgun barrels were made.

In pump-action shotguns, a linearly sliding fore-end handguard (i.e. pump) is manually moved back-and-forth like a hand pump to work the action, extracting the spent shell and inserting a new round, while cocking the hammer or striker. A pump-action shotgun is typically fed from a tubular magazine underneath the barrel, which also serves as a guide rail for the pump. The rounds are fed in one by one through a port in the receiver, where they are lifted by a lever called the elevator and pushed forward into the chamber by the bolt. A pair of latches at the rear of the magazine hold the rounds in place and facilitate feeding of one shell at a time. If it is desired to load the gun fully, a round may be loaded through the ejection port directly into the chamber, or cycled from the magazine, which is then topped off with another round. Well-known examples include the Winchester Model 1897, Remington 870, and Mossberg 500/590.

Gauge

The gauge number is determined by the weight, in fractions of a pound, of a solid sphere of lead with a diameter equal to the inside diameter of the barrel. So, a 10-gauge shotgun nominally should have an inside diameter equal to that of a sphere made from one-tenth of a pound of lead. Each gauge has a set caliber. By far the most common gauges are 12 (0.729 in, 18.5mm diameter) and 20 (0.614 in, 15.6mm); other, less common gauges include 10, 16, 24, 28, 32, and 67 (.410 bore).

Different gauges have different typical applications. 12-gauge shotguns are common for hunting geese, large ducks, or other big larger gamebirds; professional skeet and trap shooting; military applications; and home-defense applications. 16-gauge shotguns were once common for hunters who wanted to use only a single shotgun for gamebirds normally pursued with 12- or 20-gauge shotguns, but have become rarer in recent years. 20-gauge shotguns are often used for gamebirds such as doves, smaller ducks, and quail. 28-gauge shotguns are not as common but are classic quail-hunting guns. .410-gauge shotguns are typically used for squirrel hunting or for sportsmen seeking the challenge of killing game with a smaller load.

Other, less common shotgun cartridges have their own unique uses. Ammunition manufacturer CCI produces 9mm Parabellum (.355 in.) and several other popular pistol calibers up to .45 ACP (11.43mm), as well as smaller calibers such as .22 Long Rifle (5.5mm) and .22 Magnum (5.5mm). These are commonly called snake shot cartridges. Larger gauges, up to 4 bore, too powerful to shoulder, have been built, but were generally affixed to small boats and referred to as punt guns. These were used for commercial waterfowl hunting, to kill large numbers of birds resting on the water.

Handguns have also been produced that are capable of firing either .45 (Long) Colt or .410 shotgun shells from the same chamber; they are commonly known as "snake guns". Derringers such as the "Snake Slayer and Cowboy Defender" are popular among some outdoorsmen in the South and Southwest regions of the United States. There are also some revolvers, such as the Taurus Judge and Smith & Wesson Governor, that are capable of shooting the .45LC/.410 rounds; but, as with derringers, they are not considered shotguns.

The .410 bore (10.4 mm) is unusual, being measured in inches, and would be approximately 67 "real" gauge, though its short hull versions are nominally called 36-gauge in Europe. It uses a relatively small charge of shot. It is used for hunting and for skeet. Because of its very light recoil (approx 10 N), it is often used as a beginner's gun. However, the small charge and typically tight choke make it more difficult to hit targets. It is also frequently used by expert shooters because of the difficulty, especially in expensive side-by-side and over-under models for hunting small bird game, such as quail and doves. Inexpensive bolt-action .410 shotguns are a very common first hunting shotgun among young preteen hunters, as they are used mostly for hunting squirrels, while additionally teaching bolt-action manipulation skills that will transfer easily later to adult-sized hunting rifles. Most of these young hunters move up to a 20-gauge within a few years, and to 12-gauge shotguns and full-size hunting rifles by their late teens. Still, many who are particularly recoil-averse choose to stay with 20-gauge shotguns all their adult life, as it is a suitable gauge for many popular hunting uses.

Shot

Most shotguns are used to fire "a number of ball shot" (pellets), in addition to slugs and sabots. The ball shot is, for the most part, made of lead, but this has been partially replaced by bismuth, steel, tungsten-iron, tungsten-nickel-iron, and even tungsten polymer loads. Non-toxic loads are required by federal law for waterfowl hunting in the U.S., as the shot may be ingested by the waterfowl, which some authorities believe can lead to health problems due to the lead exposure. Shot is termed either birdshot or buckshot depending on the shot size. Informally, birdshot pellets have a diameter smaller than 5 mm (0.20 in) and buckshot are larger than that. Pellet size is indicated by a number; for birdshot, this ranges from the smallest 12 (1.2 mm, 0.05 in) to 2 (3.8 mm, 0.15 in) and then BB (4.6 mm, 0.18 in).

For buckshot, the numbers start and end with 4, 3, 2, 1, 0 ("single-aught"), 00 ("double-aught"), 000 ("triple-aught"), and 0000 ("quadruple-aught"). A different informal distinction is that "birdshot" pellets are small enough that they can be measured into the cartridge by weight, and simply poured in, whereas "buckshot" pellets are so large they must be stacked inside the cartridge in a fixed geometric arrangement to fit. The diameter in hundredths of an inch of bird shot sizes from No. 9 to No. 1 can be obtained by subtracting the shot size from 17. Thus, No. 4 bird shot is 17 – 4 = 13 = 0.13 inches (3.3 mm) in diameter. Different terminology is used outside the United States. In England and Australia, for example, 00 buckshot cartridges are commonly referred to as "S.G." (Swanshot gauge) cartridges.

Pattern and choke

Shot, small and round and delivered without spin, is ballistically inefficient. As the shot leaves the barrel, it begins to disperse in the air. The resulting cloud of pellets is known as the shot pattern, or shotgun shot spread. The ideal pattern would be a circle with an even distribution of shot throughout, with a density sufficient to ensure enough pellets will intersect the target to achieve the desired result, such as a kill when hunting or a break when shooting clay targets. In reality, the pattern is closer to a Gaussian (normal) distribution, with a higher density in the center that tapers off at the edges. Patterns are usually measured by firing at a 30-inch (76 cm) diameter circle on a large sheet of paper placed at varying distances. The hits inside the circle are counted, and compared to the total number of pellets, and the density of the pattern inside the circle is examined. An "ideal" pattern would put nearly 100% of the pellets in the circle and would have no voids—any region where a target silhouette will fit and not cover 3 or more holes is considered a potential problem.

A constriction in the end of the barrel known as the choke is used to tailor the pattern for different purposes. Chokes may either be formed as part of the barrel at the time of manufacture, by squeezing the end of the bore down over a mandrel, or by threading the barrel and screwing in an interchangeable choke tube. The choke typically consists of a conical section that smoothly tapers from the bore diameter down to the choke diameter, followed by a cylindrical section of the choke diameter. Briley Manufacturing, a maker of interchangeable shotgun chokes, uses a conical portion about three times the bore diameter in length, so the shot is gradually squeezed down with minimal deformation. The cylindrical section is shorter, usually 0.6 to 0.75 inches (15 to 19 millimetres). The use of interchangeable chokes has made it easy to tune the performance of a given combination of shotgun and shotshell to achieve the desired performance.

The choke should be tailored to the range and size of the targets. A skeet shooter shooting at close targets might use 127 micrometres (0.005 inches) of constriction to produce a 76 cm (30 in) diameter pattern at a distance of 19 m (21 yd). A trap shooter shooting at distant targets might use 762 micrometres (0.030 inches) of constriction to produce a 76 cm (30 in) diameter pattern at 37 m (40 yd). Special chokes for turkey hunting, which requires long range shots at the small head and neck of the bird, can go as high as 1500 micrometres (0.060 inches). The use of too much choke and a small pattern increases the difficulty of hitting the target, whereas the use of too little choke produces large patterns with insufficient pellet density to reliably break targets or kill game. "Cylinder barrels" have no constriction.

Barrel length

Shotguns generally have longer barrels than modern rifles. Unlike rifles, however, the long shotgun barrel is not for ballistic purposes; shotgun shells use small powder charges in large diameter bores, and this leads to very low muzzle pressures (see internal ballistics) and very little velocity change with increasing barrel length. According to Remington, modern powder in a shotgun combusts completely in 25 to 36 cm (10–14 in) barrels.

Since shotguns are generally used for shooting at small, fast-moving targets, it is important to lead the target by firing slightly ahead of the target, so that when the shot reaches the range of the target, the target will have moved into the pattern.

Shotguns made for close ranges, where the angular speed of the targets is great (such as skeet or upland bird hunting), tend to have shorter barrels, around 24 to 28 inches (61–71 cm). Shotguns for longer range shooting, where angular speeds are small (trap shooting; quail, pheasant, and waterfowl hunting), tend to have longer barrels, 28 to 36 inches (91 cm). The longer barrels have more angular momentum, and will therefore swing more slowly but more steadily. The short, low angular momentum barrels swing faster, but are less steady. These lengths are for pump or semi-auto shotguns; break-open guns have shorter overall lengths for the same barrel length, and so will use longer barrels. The break-open design saves between 8 and 15 cm (3–6 in) in overall length, but in most cases pays for this by having two barrels, which adds weight at the muzzle. Barrels for shotguns have been getting longer as modern steels and production methods make the barrels stronger and lighter; a longer, lighter barrel gives the same inertia for less overall weight.

Shotguns for use against larger, slower targets generally have even shorter barrels. Small game shotguns, for hunting game like rabbits and squirrels, or shotguns for use with buckshot for deer, are often 56 to 61 cm (22–24 in).

Shotguns intended for all-round hunting are a compromise, but a 72 to 74 cm (28–29 in) barrel pump-action 12-gauge shotgun with a modified choke can serve admirably for use as one gun intended for general all-round hunting of small-game such as quails, rabbits, pheasants, doves, and squirrels in semi-open wooded or farmland areas in many parts of the eastern U.S. (Kentucky, Indiana, Tennessee) where dense brush is less of a hindrance and the ability to have more reach is important. For hunting in dense brush, shorter barrel lengths are often preferred when hunting the same types of game.

Caliber conversion sleeves

Shotguns are well suited for the use of caliber conversion sleeves, allowing most single- and double-barrel shotguns to fire a wide range of ammunition. The X Caliber system consists of eight adapter sleeves that allow the 12-gauge models to fire: .380 ACP, 9mm Luger, .38 Special, .357 Magnum, .40 S&W, .44 Special, .44 Magnum, .45 ACP, .45 Long Colt, .410 gauge and 20-gauge ammunition. They even make four adapter sleeves that allow the 20-gauge models to fire: 9mm Luger, .38 Special, .357 Magnum, .45 ACP, .45 Long Colt, and .410 gauge ammunition.

Ammunition

The extremely large caliber of shotgun shells has led to a wide variety of different ammunition.

Shotshells are the most commonly used round, filled with lead or lead substitute pellets.

Of this general class, the most common subset is birdshot, which uses a large number (from dozens to hundreds) of small pellets, meant to create a wide "kill spread" to hunt birds in flight. Shotshells are described by the size and number of the pellets within, and numbered in reverse order (the smaller the number, the bigger the pellet size, similar to bore gauge). Size nine (#9) shot is the smallest size normally used for hunting and is used on small upland game birds such as dove and quail. Larger sizes are used for hunting larger upland game birds and waterfowl.

Buckshot is similar to but larger than birdshot, and was originally designed for hunting larger game, such as deer (hence the name). While the advent of new, more accurate slug technologies is making buckshot less attractive for hunting, it is still the most common choice for police, military, and home defense uses. Like birdshot, buckshot is described by pellet size, with larger numbers indicating smaller shot. From the smallest to the largest, buckshot sizes are: #4, (called "number four"), #1, 0 ("one-aught"), 00 ("double-aught"), 000 ("triple-aught") and 0000 ("four-aught"). A typical round for defensive use would be a 12-gauge 2+3⁄4-inch (7.0 cm) length 00 buck shell, which contains 9 pellets roughly 8.4 millimetres (0.33 in) in diameter, each comparable to a .38 Special bullet in damage potential. New "tactical" buckshot rounds, designed specifically for defensive use, use slightly fewer shot at lower velocity to reduce recoil and increase controllability of the shotgun. There are some shotgun rounds designed specifically for police use that shoot effectively from 50 yards (46 m) with a 20-inch-diameter (510 mm) grouping of the balls.

Slug rounds are rounds that fire a single solid slug. They are used for hunting large game and in certain military and law enforcement applications. Modern slugs are moderately accurate, especially when fired from special rifled slug barrels. They are often used in "shotgun-only" hunting zones near inhabited areas, where rifles are prohibited due to their greater range.

Specialty ammunition

The unique properties of the shotgun, such as large case capacity, large bore, and the lack of rifling, has led to the development of a large variety of specialty shells, ranging from novelties to high-tech military rounds.

Brenneke and Foster type slugs have the same basic configuration as normal slugs but have increased accuracy. The hollowed rear of the Foster slug improves accuracy by placing more mass in the front of the projectile, therefore inhibiting the "tumble" that normal slugs may generate. The Brenneke slug takes this concept a bit further, with the addition of a wad that stays connected to the projectile after discharge, increasing accuracy. Both slugs are commonly found with fins or ribs, which are meant to allow the projectile to safely squeeze down during passage through chokes, but they do not increase stability in flight.

Flechette rounds contain aerodynamic darts, typically from 8 to 20 in number. The flechettes provide greatly extended range due to their aerodynamic shape and improved penetration of light armor. American troops during the Vietnam War packed their own flechette shotgun rounds, called beehive rounds after the similar artillery rounds. However, terminal performance was poor due to the very light weight of the flechettes, and their use was quickly dropped.

Grenade rounds use exploding projectiles to increase long range lethality. These are currently experimental, but the British FRAG-12, which comes in High Explosive (HE), High Explosive Armor-piercing (HEAP) and High Explosive Fragmenting Antipersonnel (HEFA) forms, is under consideration by military forces.

Flexible baton rounds, commonly called bean bags, fire a fabric bag filled with birdshot or a similar loose, dense substance. The "punch" effect of the bag is useful for knocking down targets; the rounds are used by police to subdue violent suspects. The bean bag round is by far the most common less-lethal round used. Due to the large surface area of these rounds, they lose velocity rapidly, and must be used at fairly short ranges to be effective, though use at extremely short ranges, under 3 m (9.8 ft), can result in broken bones or other serious or lethal injuries. The rounds can also fly in a frisbee-like fashion and cut the person or animal being fired at. For this reason, these types of rounds are referred to as less-lethal, as opposed to less-than-lethal.

Uses

The typical use of a shotgun is against small and fast-moving targets, often while in the air. The spreading of the shot allows the user to point the shotgun close to the target, rather than having to aim precisely as in the case of a single projectile. The disadvantages of shot are limited range and limited penetration of the shot, which is why shotguns are used at short ranges, and typically against smaller targets. Larger shot sizes, up to the extreme case of the single projectile slug load, result in increased penetration, but at the expense of fewer projectiles and lower probability of hitting the target.

Aside from the most common use against small, fast-moving targets, the shotgun has several advantages when used against still targets. First, it has enormous stopping power at short range, more than nearly all handguns and many rifles. Though many believe the shotgun is a great firearm for inexperienced shooters, the truth is, at close range, the spread of shot is not very large at all, and competency in aiming is still required. A typical self-defense load of buckshot contains 8–27 large lead pellets, resulting in many wound tracks in the target. Also, unlike a fully jacketed rifle bullet, each pellet of shot is less likely to penetrate walls and hit bystanders (though in the case of traditional 00-Buck, overpenetration of soft and hard targets may be an issue). It is favored by law enforcement for its low penetration and high stopping power.

On the other hand, the hit potential of a defensive shotgun is often overstated. The typical defensive shot is taken at very close ranges, at which the shot charge expands no more than a few centimeters. This means the shotgun must still be aimed at the target with some care. Balancing this is the fact that shot spreads further upon entering the target, and the multiple wound channels are far more likely to produce a disabling wound than a rifle or handgun.

Sporting

Some of the most common uses of shotguns are the sports of skeet shooting, trap shooting, and sporting clays. These involve shooting clay discs, also known as clay pigeons, thrown in by hand and by machine. Both skeet and trap competitions are featured at the Olympic Games.

Hunting

The shotgun is popular for bird hunting (called "game-shooting" in the United Kingdom, where "hunting" refers to hunting mammals with a pack of hounds), it is also used for more general forms of hunting especially in semi-populated areas where the range of rifle bullets may pose a hazard. Use of a smoothbore shotgun with a rifled slug or, alternatively, a rifled barrel shotgun with a sabot slug, improves accuracy to 100 m (110 yd) or more. This is well within the range of the majority of kill shots by experienced hunters using shotguns.

However, given the relatively low muzzle velocity of slug ammunition, typically around 500 m/s (about 1600 feet per second), and the blunt, poorly streamlined shape of typical slugs (which cause them to lose velocity very rapidly, compared to rifle bullets), a hunter must pay close attention to the ballistics of the particular ammunition used to ensure an effective and humane kill shot.

At any reasonable range, shotgun slugs make effective lethal wounds due to their tremendous mass, reducing the length of time that an animal might suffer. For example, a typical 12-gauge shotgun slug is a blunt piece of metal that could be described as an 18 mm (.729 inch) caliber that weighs 28 grams (432 grains). For comparison, a common deer-hunting rifle round is a 7.62 mm (.308 inch) slug weighing 9.7 grams (150 grains), but the dynamics of the rifle cartridge allow for a different type of wound, and a much further reach.

Shotguns are often used with rifled barrels in locations where it is not lawful to hunt with a rifle. Typically, a sabot slug is used in these barrels for maximum accuracy and performance. Shotguns are often used to hunt whitetail deer in the thick brush and briers of the Southeastern and upper Midwestern United States, where, due to the dense cover, ranges tend to be close – 25m or less.

Sabot slugs are essentially very large hollow point bullets, and are streamlined for maximum spin and accuracy when shot through a rifled barrel. They have greater ranges than older Foster and Brenneke-type slugs.

People often use semiautomatic or pump-action shotguns for hunting waterfowl to small game.

Industrial

Another use are industrial shotguns, used for buildup of slag in kilns. They are similar in usage but differ than powder-actuated tools. These are also used in the mining and cement industry for knocking down overhands and residue buildup, etc. A known example of an industrial shotgun is the 8-gauge Remington MasterBlaster.

Law enforcement

In many countries, especially the United States and Canada, shotguns are widely used as a support weapon by police forces. One of the rationales for issuing shotguns is that, even without much training, an officer will probably be able to hit targets at close to intermediate range, due to the "spreading" effect of buckshot. This is largely a myth, as the spread of buckshot at 25 feet averages 8 inches, which is still very capable of missing a target. Some police forces are replacing shotguns in this role with carbine rifles such as AR-15s. Shotguns are also used in roadblock situations, where police are blocking a highway to search cars for suspects. In the U.S., law enforcement agencies often use riot shotguns, especially for crowd and riot control where they may be loaded with less-lethal rounds such as rubber bullets or bean bags. Shotguns are also often used as breaching devices to defeat locks.

Military

Shotguns are common weapons in military use, particularly for special purposes. Shotguns are found aboard naval vessels for shipboard security, because the weapon is very effective at close range as a way of repelling enemy boarding parties. In a naval setting, stainless steel shotguns are often used, because regular steel is more prone to corrosion in the marine environment. Shotguns are also used by military police units. U.S. Marines have used shotguns since their inception at the squad level, often in the hands of NCOs, while the U.S. Army often issued them to a squad's point man. Shotguns were modified for and used in the trench warfare of World War I, in the jungle combat of World War II and the Vietnam War. Shotguns were also used in the Iraq War, being popular with soldiers in urban combat environments. Some U.S. units in Iraq used shotguns with special frangible breaching rounds to blow the locks or hinges off doors when making a surprise entry into a dwelling.

Recently, shotguns have proven to be one of the few effective means of repelling incoming drones in military conflicts due to their heightened ability to shoot and hit fast and small targets with the use of pelletted ammo such as buckshot and birdshot shells.

Home and personal defense

Shotguns are a popular means of home defense for many of the same reasons they are preferred for close-quarters tasks in law enforcement and the military.

Legal issues

Globally, shotguns are generally not as heavily regulated as rifles or handguns, likely because they lack the range of rifles and are not easily concealable as handguns are; thus, they are perceived as a lesser threat by legislative authorities. The main exception is a sawed-off shotgun, especially a lupara, as it is more easily concealed than a normal shotgun.

Australia

Within Australia, all shotguns manufactured after 1 January 1901 are considered firearms and are subject to registration and licensing. Most shotguns (including break-action, bolt-action and lever-action shotguns) are classed as "Category A" weapons and, as such, are comparatively easy to obtain a licence for, given a legally recognised "legitimate reason" (compare to the British requirement for "good reason" for a FAC), such as sport shooting or hunting. However, pump-action and semi-automatic shotguns are classed as "Category C" (magazine capacity no more than 5 rounds) or "Category D" (magazine capacity more than 5 rounds) weapons; a licence for this type of firearm is, practically speaking, unavailable to the average citizen due to the difficulty and red tape of acquiring one. For more information, see gun politics in Australia.

Canada

Canada has three classifications of firearms: non-restricted, restricted, and prohibited. Shotguns are found in all three classes.

All non-restricted shotguns must have an overall length of at least 660 mm (26 in). Semi-automatic shotguns must also have a barrel length of no less than 469.9 mm (18.50 in) and with a capacity of 5 shells or less in the magazine to remain non-restricted. All other shotgun action types (pump/slide, break open, lever, bolt) do not have a magazine limit restriction or a minimum barrel length provided the overall length of the firearm remains more than 660 mm (26 in) and the barrel was produced by an approved manufacturer. Shotgun barrels may only be reduced in length to a minimum of 457 mm (18.0 in). Non-restricted shotguns may be possessed with any Possession and Acquisition Licence (PAL) or Possession-Only License (POL) and may be transported throughout the country without special authorization and may be used for hunting certain species at certain times of the year.

Semi-automatic shotguns with a barrel length of less than 469.9 mm (18.50 in) are considered restricted and any shotgun that has been altered so its barrel length is less than 457 mm (18.0 in) or if its overall length is less than 660 mm (26 in) is considered prohibited. Restricted and prohibited shotguns may be possessed with a PAL or POL that has been endorsed for restricted or prohibited grandfathered firearms. These shotguns require special Authorization to Transport (ATT).

The Canadian Firearms Registry was a government-run registry of all legally owned firearms in Canada. The government provided amnesty from prosecution to shotgun and rifle owners if they fail to register non-restricted shotguns and rifles. The long gun portion of the registry was scrapped in 2011.

See online for an official Canadian list of non-restricted and restricted and prohibited firearms.

United Kingdom

In the United Kingdom, a Shotgun Certificate (SGC) is required to possess a "Section 2" shotgun. These cost £50 and can only be denied if the chief of police in the area believes and can prove that the applicant poses a real danger to the public, or if the applicant has been convicted of a crime punishable by imprisonment for a term of three years or more or if the applicant cannot securely store a shotgun (gun clamps, wire locks and locking gun cabinets are considered secure). The round number restrictions apply only to the magazine, not the chamber, so it is legal to have a single-barreled semi-auto or pump-action shotgun that holds more than 3 rounds in total, or a shotgun with separate chambers (which would need to also be multi-barrelled). For a shotgun to qualify as a section 2 shotgun, it must meet the following criteria:

Prior to an SGC being issued, an interview is conducted with the local Firearms Officer. In the past, this was a duty undertaken by the local police, but after the 1984 PACE Act and 1992 PEACE Act this function has been shifting more out to civilian staff. The 1984 PACE Act was established after many injustices occurring in the 1970s, and provided (and provides) protection to the citizens and their privacy whether free or detained. This act pushes for "interviews" to be conducted, rather than interrogations. These interviews must be recorded and on record, and the officer is not allowed to hide parts of said interview or evidence. The 1992 PEACE Act added upon this, which pushed for more of an "interview" rather than a sometimes coercive interrogation that may result in a false positive when it comes to crime. According to the U.S. Department of Justice's journal on the effects of these acts, they have reduced turnout of information gained from said interviews, and now almost only novice offender is likely to give information and be affected by said interviews according to a study in 1986. In the process the officer will check the location and suitability of the gun safe that is to be used for storage and they (or an "interview specialist") will conduct a general interview to establish the reasons behind the applicant requiring an SGC.

An SGC holder can own any number of shotguns meeting these requirements so long as he/she can store them securely. No certificate is required to own shotgun ammunition, but one is required to buy it. There is no restriction on the amount of shotgun ammunition that can be bought or owned. There are also no rules regarding the storage of ammunition.

However, shotgun ammunition which contains fewer than 6 projectiles requires a section 1 Firearms Certificate (FAC). Shotguns with a magazine capacity greater than 2 rounds are also considered to be section 1 firearms and, as such, require an FAC to own. An FAC costs £50 but is much more restrictive than an SGC. The applicant must nominate two referees who are known to the applicant to vouch for his or her character; a new 'variation' is required for each new caliber of gun to be owned; limits are set on how much ammunition a person can own at any one time; and an FAC can be denied if the applicant does not have sufficient 'good reason'. 'Good reason' generally means hunting, collecting, or target shooting – though other reasons may be acceptable. Personal defense is not an acceptable reason.

United States

In the U.S., federal law prohibits shotguns from being capable of holding more than three shells including the round in the chamber when used for hunting migratory gamebirds such as doves, ducks, and geese. For other uses, a capacity of any number of shells is generally permitted. Most magazine-fed shotguns come with a removable magazine plug to limit the capacity to 2, plus 1 in the chamber, for a total of 3 rounds, while hunting migratory gamebirds. Certain states have restrictions on magazine capacity or design features under hunting or assault weapon laws.

Shotguns intended for defensive use have barrels as short as 18 inches (46 cm) for private use (the minimum shotgun barrel length allowed by law in the United States without federal registration). Barrel lengths of less than 18 inches (46 cm) as measured from the breechface to the muzzle when the weapon is in battery, or have an overall length of less than 26 inches (66 cm) are classified as short-barreled shotguns (SBS) under the 1934 National Firearms Act and are regulated. A similar short-barreled weapon having a pistol grip may be classified as an AOW or "Any Other Weapon" or "Firearm", depending on barrel length. A shotgun is defined as a weapon (with a buttstock) designed to be fired from the shoulder. The classification varies depending on how the weapon was originally manufactured.

Shotguns used by military, police, and other government agencies are regulated under the National Firearms Act of 1934; however, they are exempt from transfer taxes. These weapons commonly have barrels as short as 12 to 14 inches (30 to 36 centimetres) so that they are easier to handle in confined spaces. Non-prohibited private citizens may own short-barreled shotguns by passing extensive background checks (state and local laws may be more restrictive) as well as paying a $200 federal tax and being issued a stamp. Defensive shotguns sometimes have no buttstock or will have a folding stock to reduce overall length even more when required. AOWs transfer with a $5 tax stamp from the BATFE.