Shotguns Demystified

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Shotguns Demystified

Shotguns – and shotgun ammunition – are not very simple, easy to understand topics. While rifle and pistol ammunition are not as complicated, the nature and versatility of shotguns means that there are additional factors to consider and understand.

The most obvious difference between shotguns and shotshell types is gauge. I’ll start with that.


Shotguns, and shotgun shells, are sized by gauge. Unlike rifles and pistols, where higher numbers generally indicate larger and more powerful calibers, shotgun gauges become progressively larger and more powerful as the gauge number decreases. As you might imagine, the larger and more powerful shotguns also offer greater recoil, which may not be desirable.

The three most commonly available shotgun gauges in the United States are 12, 20, and .410. Still fairly common, though not as much as the other three, is 28 gauge. Finally, although 10 gauge and 16 gauge ammunition can still be found in specialty stores, newly manufactured firearms in these gauges are very rare.

Gauge, put simply, refers to the number of lead balls in the diameter of the shotgun bore that equal 1 pound. In other words, 12 lead balls with the exact diameter of a 12 gauge shotgun bore (.73″) weigh 1 pound, while it would take 20 lead balls in the diameter of the smaller 20 gauge shotgun bore (.62″) to equal 1 pound. The exception to this rule is .410 – it’s technically 68 gauge, although no one ever refers to it by this name, and it was at one point in time referred to by ammo manufacturers as 36 gauge!

While .410 shotguns are quite useful for very young or small shooters, adults of almost all shapes and sizes should have no problems handling a 20 gauge shotgun, especially if low recoil ammunition is used. The 20 gauge offers a significant step over .410 in terms of utility and power, and is a better choice for survival purposes unless an extremely lightweight or small firearm is an absolute necessity. 12 gauge is similarly more powerful than 20 gauge, although the difference is not as great. Still, it should be noted that skill (practice and experience) with whatever you weapon you choose is more important than the raw data surrounding that weapon.

Shell Length

Within each gauge are various shell lengths. These numbers are defined as the length of the shell after it has been fired, not the length of the unfired shell – the front of the plastic shotshell hull opens forward as it is fired, causing the shell to become longer.

Shotguns will be stamped with the length of the shells they can fire – for example, 12 gauge shotgun ammunition is referred to as “2 3/4 inch” or “3 inch”. A common name for a shotgun that can fire a 3 inch shell is Magnum, while shotguns capable of firing 3 1/2 inch shells are often referred to as Super Magnum. Shotguns are capable of firing a shell that is shorter than what might be specified on the barrel, but should not be loaded with longer than what the barrel is stamped with.

Types of Shotshells

There are three basic types of shotgun shells – slugs, buckshot, and birdshot. Slug shells fire one large projectile, which is, naturally, called a slug. Buckshot shells fire between a few and a few dozen smaller projectiles of various diameters. Birdshot shells are loaded with hundreds of tiny projectiles that, like buckshot, vary in diameter.

The amount of shot and the size of the shot depend on the gauge of the shotgun and the length of the shotshell. Choosing which type of shotshell to buy depends on what you intend to use it for.

Uses Of Shotguns & Shotshells

Shotguns are extremely versatile, and are far more than the short-range weapons they are often made out to be in TV shows and movies. With certain types of slugs, hunters across America take deer and other game animals from hundreds of yards away with shotguns each year. Of course, many more people use shotguns for what we normally think of shotguns being used for, such as bird hunting or home defense. Still, you should be aware that you can do many things with just one shotgun, especially if it is a type that allows you to swap barrels.


Slugs are used for hunting as well as defensive purposes. Because they consist of one large projectile, they offer the chance to do a large amount of damage with one well-placed shot.

Slugs are referred to by weight, most commonly in ounces. The heavier and faster the slug, the more damage it will do, and the more recoil shooter will feel. Some slugs are referred to as rifled slugs, but they do not provide any extra accuracy over non-rifled slugs – they are simply designed to be compressed through a shotgun choke tube, which I will discuss later.

Another type of slug is the sabot slug. This consists of a lead or copper projectile, significantly smaller than the diameter of the shotgun bore, which is held inside a plastic “sabot” that flies apart as soon as it is outside of the barrel, leaving the smaller projectile to fly towards the target with a higher velocity than a larger and heavier slug. This type of shotshell is generally intended for rifled shotgun barrels, and is surprisingly accurate even at 200 or 300 yards.

Slugs will often penetrate thicker barriers such as car doors and windshields without being deflected or slow down as much as pistol bullets and even some rifle bullets, which is why some law enforcement agencies use slugs. When in areas where encounters with bears or other large predators are likely, slugs are the most common shotshell choice, for they will penetrate tissue and bone far better than buckshot or birdshot.


Buckshot, as the name implies, was originally intended for hunting deer sized animals. Like slugs, they are used for hunting as well as defensive purposes. At relatively close ranges, it offers the hunter or shooter a small amount of leeway in terms of missing the vital zone of an animal.

However, buckshot does not meaningfully spread at close range, despite the common myth of not needing to aim a shotgun. For example, at 5 yards, the largest group one is likely to see from 12 or 20 gauge buckshot could be covered by a closed fist.

Buckshot is referred to by “number.” Like gauge, as the number decreases, size increases. Buckshot sizes include 4, 3, 2, 1, 0, 00, 000, and 0000. It is possible to describe buckshot as being roughly equivalent to pistol ammunition diameter – “#4 buck” is a little bigger than a .22 bullet, while “0000 buck” is almost as big as a .40 caliber bullet.

Because buckshot is round, a single buck pellet will weigh less than a single pistol bullet of the same or similar diameter. That said, a shotgun firing, say, nine 000 buck pellets with roughly the same diameter as a 9 mm pistol bullet offers a certain advantage over the pistol, which can only fire one projectile at a time.

The most common buckshot size for a 12 gauge shotgun is 00. This shot is .33 inches in diameter, and a 12 gauge shotgun with a 2 3/4″ or 3″ shell holds between 8 and 15 pellets of this size. 20 gauge shotguns are often found with smaller shot sizes, such as 20 pellets of #3 buck, because this smaller shot stacks better inside the smaller 20 gauge shotshell hull.


Like buckshot, the name implies what this type of shot is intended for, it is generally referred to by numbers, and it gets bigger as the numbers get smaller. Unlike buckshot, birdshot may also be referred to by letters, and birdshot is generally very small, with some of the most common shot sizes (for example, 7 and 8 ) being around .1″ in diameter.

While buckshot shells are described with the size and number of pellets, birdshot is measured in weight, because there are so many tiny pellets in each shell. For example, a “1 oz #8 shotshell” contains 410 pellets that are .09″ in diameter.

Birdshot is designed to humanely kill birds and other small animals without causing too much tissue damage, which could result in there being too little meat to recover for human nutrition purposes. Birdshot is thus ideal for survival situations where the hunting of very small game and birds may be easier or more commonly encountered than the hunting of larger animals such as deer.

However, birdshot is not intended for defense against large or violent predators, be they human or animal. It will not reliably and consistently penetrate deep enough through muscle, fatty tissue, and bone to reach vital organs, which is necessary to stop a violent attack within seconds. It is true that birdshot could cause wounds that might cause death within hours or days, but this is not desirable when seconds matter.

The largest birdshot sizes, F and FF, stop just short of #4 buckshot in size. Larger birdshot sizes are intended for, not surprisingly, larger birds. Turkey and goose hunters go for larger shot sizes than duck, dove, or quail hunters. Because these numbers can be confusing, it is common to refer to buckshot pellets as “#2 buck,” while birdshot pellets are referred to as “#2 shot.”

Because federal and state regulations prevent the use of lead shot when hunting waterfowl, ammunition manufacturers started producing shot made from steel and other materials. Steel is less dense than lead, meaning that with sizes being equal, lead retains more energy at range. However, waterfowl hunters compensate for this by choosing correspondingly larger steel shot sizes that provide roughly the same amount of energy, and thus penetration, per pellet.

Shotgun Factors

In addition to the previously mentioned chamber length, shotguns are offered with rifled and smoothbore barrels as well as various choke tubes. Also, shot selection has a major effect on recoil.

Rifled versus Smoothbore Barrels

Rifled barrels, as I touched on above, are basically intended to shoot certain types of slugs. If buckshot or birdshot are used in rifled barrels, exceptionally poor patterns and accuracy will be noted, even at very close range. However, with slugs, rifled barrels are extremely useful and accurate. For other purposes, go with a smoothbore shotgun barrel.

Choke Tubes

The purpose of a choke tube is to force the “cloud” of shot to a smaller diameter as it flies through the air. Choke varies from cylinder bore, which is simply the same diameter as the shotgun barrel, to extra full, which offers a significant constriction of barrel diameter. Some of the more common choke sizes are improved cylinder and modified, which are useful for skeet and trap shooting as well as hunting small birds at close to medium ranges. If you intend to fire slugs, you should either choose a shotgun that has a fixed cylinder bore “choke,” or purchase and install cylinder bore or skeet size choke tubes, if your shotgun has a barrel threaded for the use of choke tubes.

While it might seem that using a choke tube, thus decreasing the width of the shot pattern, would make hitting a small target harder, shot that spreads too much becomes much less effective as range increases. Yes, a large pattern means that some pellets might be on target, but there might be too few hits to make a difference, and the pellets that miss the intended target can travel on to cause unwanted or unintended damage.


Recoil is a basic function of projectile mass, projectile velocity, and firearm mass. While the operating system of the firearm, for example semi automatic versus pump action, has an effect on recoil, the most common way to reduce recoil with the shotgun is to choose a type of shot or slug loaded with a lighter or slower projectile or number of projectiles.

There are minor differences, but a shotgun loaded with a 1oz slug traveling at 1250 ft./s is going to recoil in a remarkably similar manner to a shotgun loaded with 1oz of #8 shot traveling at 1250 ft./s. It is up to the shooter whether they want to purchase low recoil ammunition, which might only have 7/8oz of shot or might only be traveling at 1150 ft./s, for example.

Because it pertains to the topic of recoil, and because you might see it on certain types of shotshell boxes, I will mention drams, which you might see as “dr. eq.” or “dram equivalent.” This is a throwback to the days when cartridges were loaded with black powder. Dram equivalent numbers were added to some shotshell boxes so that potential purchasers would understand how powerful the cartridge was compared to a standard black powder load. This is of little consequence today, and it is more important to pay attention to the other factors mentioned on the shotshell box.

Final Thoughts

The best thing to do is to purchase several different types of ammunition to test and practice with the ammo – slug, buck, birdshot, or some combination of the types – you choose. I hope that this article has given you a clear understanding of the topic – please feel free to ask questions.

Reprinted with permission from Willow Haven Outdoor.

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