Shotgun Ammo 101 | Shotgun Ammo Explained

Shotguns are probably the most versatile type of firearm. They can be used for hunting large and small game, for wingshooting, clay games (such as trap, skeet, or sporting clays), tactical use, defense, and multigun. One of the aspects of shotguns that makes them so versatile is the drastically different types of ammunition available. Let’s go over the basic types of shotgun cartridges.

Basic Types of Shotgun Shells

If we ignore “specialty” rounds like “less-lethal” (used for riot control), or the multitude of exotic/novelty rounds like the flame-throwing “dragon’s breath,” flechettes (tiny steel darts), ball-and-chain or “bolo” rounds (and the list goes on), we can categorize nearly all shotgun ammunition into one of three categories: birdshot, buckshot, or slugs.

A birdshot shotshell is a (usually) plastic outer hull filled with tiny metal pellets of various size, ranging from FF (.23” in diameter) on the larger end of the spectrum to #12 shot (.05”) on the smaller end. In the U.S., most commonly available birdshot cartridges range from size T (each pellet being roughly .20 inches in diameter) through BBB (.19), BB (.18”), B (.17”), and then progressively smaller pellets numbered 1 through 9, with number 9 shot pellets measuring .08” in diameter.

For maximum effectiveness, shotshells should always be fired from a non-rifled shotgun barrel (i.e., smooth-bore). Firing shot through a rifled bore imparts a spin on the shot cloud that spreads the shot far too quickly, and leaves a “ring” shaped pattern with large open spaces in the center that make the shot ineffective. Rifled shotgun barrels are intended only for use with slugs (usually sabot slugs; see below).

The size of the shot used in birdshot shotshells depends on what you are hunting or which targets you’re shooting, the desired effect, the distance to the targets, and other factors. For example, you might select #7 birdshot, which contains hundreds of smaller pellets, if you are using your shotgun to hunt light-skinned birds or small animals (or shooting clay targets), but you might use #5 on larger, wild pheasants late in the season when their coat of feathers is thicker and you need more penetration for an ethical kill. For larger ducks and geese for which steel shot is required in most locations, you might select BB, BBB, or even T shot to get the effective level of penetration with the lighter, steel shot.

A buckshot cartridge is constructed similarly to birdshot, except that the pellets are much larger in size and there are far fewer of them. While a typical shotshell of #8 birdshot contains hundreds of tiny, lead pellets, a common “double-aught” (00) buckshot load might contain only 8 or 9 .33” lead balls. Buckshot is so named because it was designed for hunting larger game, such as deer (buck), but it is also devastatingly effective as a tactical or defensive cartridge.

Common sizes of buckshot in the US range in progressively larger sizes from #4 buckshot at .24” in diameter, through 3, 2, 1, then 0 at .32”, 00 at .33”, and finally “triple-aught” (000) at .36” for each pellet.

Slug Cartridges

Slug cartridges, instead of small, round lead pellets, contain a single, large metal bullet loaded in a plastic hull and are typically used for hunting large game or for defense. You should never shoot at an aerial target with a slug, since the “bullet” travels in a trajectory similar to a rifle or handgun bullet and can remain lethal for hundreds of yards. (Birdshot pellets have much less mass and lose their lethal energy within about 80 to 100 yards, depending on the size of the shot.)

Slugs are available in two common varieties: so-called “rifled” or “Foster-type” slugs are soft lead, with angled riflings molded into the sides to allow them to swage down through a shotgun choke safely. (Despite the confusing name, “rifled slugs” are intended to be fired in smoothbore barrels, and the “riflings” do not impart any spin to the projectile, despite what the experts hanging around your local gun counter may tell you.)

“Sabot” (SAY-bow) slug cartridges contain a smaller-diameter projectile, often with a hollow point, contained within a plastic housing or “sabot” that breaks away from the slug after leaving the barrel. This allows sabot slugs to be fired through rifled shotgun barrels, and they can be surprisingly accurate.

In some states, deer hunters are prohibited from using traditional rifles and are required to use shotguns for hunting large game, especially in more densely populated areas.

Always Use the Correct Gauge

Shotguns are available in many different “gauges” or calibers. The most common gauge in North America is 12 gauge. The number corresponding to the gauge refers to the number of pure lead balls of bore diameter that weigh one pound. Simple, right? Not really, but that’s still how shotgun calibers are named. A 20 gauge has a smaller bore diameter (and smaller shells) than a 12 gauge, because it takes 20 lead balls the size of the bore to weigh one pound, while a 12 gauge takes only 12. A 28 gauge is, of course, smaller still. The exception is a .410 bore, which is the smallest common shotgun caliber. For some reason the .410 leaves the “gauge” naming convention behind and is so named simply because the bore is .410” in diameter (which is around 67 ½ gauge). So, calling a .410 bore shotgun a “four-ten gauge” is incorrect.

You should always make sure that the gauge of your ammo matches the gauge of your firearm. For example, if you have a 12-gauge shotgun, you need to use 12-gauge ammo (of the appropriate length; see below). If you have a 20-gauge shotgun, you need to use 20-gauge ammo.

This might sound somewhat obvious. But it is possible to put a smaller shell into the chamber of a larger-gauge gun. The problem is that the shell will usually slide partially down the barrel and can obstruct the barrel, causing a dangerous, potentially lethal situation. As with all firearms, it’s vitally important to always use the right ammunition for your gun.

Pick the Right Shell Length

Shotgun shells come in different lengths. The longer the shell, generally the more powder and more shot it contains. The chamber size for a modern, standard shotgun is 2 3/4 inches for all gauge shotguns. There are also some that have a 3-inch chamber, and specialty hunting shotguns that have 3 ½” chambers.

There are three different common shell lengths:

1. Standard shells that are 2 3/4 inches long
2. Magnum shells that are 3 inches long
3. Super-magnum shells that are 3 1/2 inches long

Please note: the stated length of the cartridge refers to the CHAMBER, or the length of the cartridge hull AFTER FIRING. In other words, a 3” cartridge will measure a little less than 3” before firing. After firing, the hull opens up to let the shot out, and measures approximately 3”.

You should always use a shell that is the same length or shorter than the chamber of your shotgun. If your gun has a 3-inch chamber, you can safely use shells that marked 3” or 2 ¾”.

Choosing the right shotgun shell matters. So does choosing the right gun safe. Visit your local Liberty Safe dealer to find the right safe for your shotgun.

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