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.