How Do Bullets and Shells Differ?
It doesn’t take long once you enter the world of firearms to understand that there are many variations on verbiage. Oftentimes, those variations occur because people are using different words to discuss the kinds of ammo that handguns, rifles or shotguns use.
Most commonly, people say that rifles and handguns shoot bullets. When talking about shotguns, people are more likely to use the term shells. There are a number of other names for what these firearms shoot, such as cartridges or rounds for handguns and rifles and slugs or shot for shotguns.
Sometimes, the different words are simply determined by the way someone speaks and can be somewhat interchangeable. But there are real differences between handgun or rifle cartridges and shotgun shells. Setting aside any similarities between things like slugs and bullets, the differences in what you shoot out of a shotgun versus other guns are actually significant.
A major way in which these types of ammunition differ has to do with the composition of shotgun shells versus that of handgun and rifle cartridges. Cartridges for other guns are very straightforward: They have a brass casing that holds the powder, a small primer on the end of the casing that will ignite the powder and the round that will be fired, which is pressed into the opening of the casing.
Shotgun shells follow the same basic pattern as that of the other rounds: They're also comprised of a primer, powder, and the projectile to be delivered. But the major difference is that shotgun shells have what is called a shot cup or wad.
The shot cup, interestingly enough, is exactly what it sounds like. It’s a small cup that holds the shot that will be fired when the trigger is pulled. Since shotgun shells are loaded with pellets called shot, there has to be something to hold them in place until they’re ready to exit the barrel. That's what the shot cup does.
The shot cup is actually covered entirely by the casing. As you are likely aware, in handgun and rifle cartridges, the bullet is exposed. This has the effect of not only making them look completely different but also alters how they operate. The shell casing is crimped at the end and it expands open with the explosion of the gases as the shot cup pushes out the pellets. Although we will discuss this in more detail in just a moment, it's important to note here that shotgun shell casings are often made of plastic whereas handgun and rifle cartridges use brass.
Cartridges vs. Shells
One of the first things you’ll notice is that the name for what shotguns shoot is a shell. This term is different from any other gun. It is similar in both function and reference to a cartridge for the other guns.
Cartridges (or rounds, as they are commonly called) are the completed package of primer, casing, gun powder and projectile. For a shotgun, this is referred to as the shell casing or just simply shells.
Shotgun shells are put together differently than cartridges for other guns. This is largely due to how other guns operate. Both handguns and rifles can actually produce tremendous chamber pressure when the round is fired; Shotguns, on the other hand, do not produce this same tremendous pressure.
This is due to the design of the shotgun. Since shotgun barrels have a larger bore than handguns or rifles, this means there is less pressure within it because the gases have more area to cover. Because other guns have smaller inner areas, the pressure in them is greater. This increased pressure requires that the casing for the cartridge be made of a stronger material than what shotguns require.
Why Is it Called a Shell?
A shotgun shell refers to the all-encompassing round in the same way the word cartridge does. The shells for a shotgun are the things that you load into it when you're ready to shoot. While the term may have changed, the function is the same.
There are competing theories as to why shotgun shells are called shells. Some say that it is because the cartridges act like a shell for the propellant, wadding and shot — meaning that it’s only there to protect the rest from outside harm. Shotshells do not need to function in the same way cartridges do because of the aforementioned chamber pressure issue, so in that regard, they truly are just a protective shell to hold things together until they need to come out.
Additionally, shotguns operate similar to how artillery is fired, and both trace their roots back to the early canon. Canons evolved into modern artillery, and the smooth-bored muskets of the past evolved into shotguns. The rounds fired by artillery are also referred to as shells, and a constant barrage of artillery on a target is referred to as shelling the target.
Because a shotgun operates in a similar manner to artillery and because shotguns fire clusters of pellets that impact in a barrage, you could say that the target is being shelled by the shotgun.
While there may be some element of truth in both stories, the reality is that the word shell comes from shell casing. It's merely a descriptor — it’s called a shell because it is a shell.
Shot vs. Bullets
This brings us to another difference between cartridges and shells. Slugs aside, shotgun shells don’t have bullets. Shotgun shells have a specified number of pellets similar to BBs in a BB gun. These pellets are called shot — hence the name shotgun.
In other types of guns, a cartridge fires out one single round that follows along the rifling of the barrel, spinning to maintain accuracy and allowing it to travel great distances. In a shotgun, the explosion sends a group of pellets down the smoothbore where they spread out rapidly as they accelerate towards the target. The difference in how these operate is night-and-day.
Think of a bullet as a precision instrument. A bullet is aimed at a specific point and fired in the hopes that it hits that specific point. A shotgun, on the other hand, is aimed at an area. Once fired, the ammo blankets that area. Where a bullet is a scalpel, shotgun shells are like a hammer. One is used for precision, the other for blunt trauma.
Types of Shot
There are different types of shot, as well. There are ones that have larger round pellets, and these are known as buckshot. Others have smaller pellets and are often called birdshot.
Buckshot, as the name implies, is intended for larger game like a buck and can even be used for self-defense purposes. Birdshot (or small game loads) is intended for birds, rodents and other varmints.
Since we’ve mentioned slugs a couple times already, now would be a good opportunity to address them. Slugs are essentially bullets designed to be fired from a shotgun. Slugs are encased in a shotgun shell instead of pellets. Since shotguns don’t have rifling, the slugs themselves are rifled. They’re great to use for self-defense but aren’t as accurate or capable of covering distances as a round from a rifle would be.
As you can see, shot shells are completely different from the rounds fired by handguns and rifles. At the same time, they operate along the same principles in many regards.
It just goes to show you that firearms are a rich and full world for you to inhabit. The more you investigate and look into every aspect of gun culture, the more you’ll see just how different yet similar everything is. If you feel like tumbling further down that rabbit hole, feel free to hang around and read some more blog posts.