Primed with Basics: Understanding Gun Ammunition Made Easy

The firearms world has seen an enormous expansion over the last few years. While it is difficult to put an exact number on it, data shows that there are at least five million new gun owners that have joined the firearms community. Many of these new gun owners are absolutely new to the gun world and have little to no preexisting knowledge. However, understanding ammunition is as important as understanding your gun.

Understanding the Ammunition You Feed Your Gun

At times, those of us who have been at it since George Washington was a private forget that people may need some guidance on the basics. One area where that is important is ammunition. To the uninitiated, the wide variety of ammunition with its sometimes-cryptic nomenclature can be overwhelming. With that in mind, let’s take a look at the basics of ammo.

Components

First up, let’s take a look at the anatomy of a bullet. This is where we make our first distinction. While the object used to fire out of guns is sometimes referred to as a bullet, the official name is cartridge. The bullet is but one of the components of the cartridge and is the projectile that is launched down the barrel.

To new shooters, ammunition can be a confusing topic. Consequently, it is important to educate yourself about the ammunition your gun needs.

The individual components of a cartridge are as follows. The case is the metal shell that houses everything together. They are usually made from brass but can also be made from steel, nickel, and even aluminum.

Inside the case, we find the propellant. While it is often referred to as gunpowder, there are a wide variety of agents used in this role. The purpose of the propellant is to burn, produce gas pressure and launch the bullet through the barrel. At the bottom of the case is the rim. This is a point that even long-time gun owners do not know.

Rimless Ammunition

Most cartridges for our semi-automatic handgun are considered rimless. Now that does not mean they do not have a rim at all, but instead, it is the same diameter as the case. Guns such as revolvers have a more pronounced rim so they can sit flush against the cylinder.

Ammo comes in a wide variety of designs and in many cases is firearm specific. That makes gaining knowledge even more important.

Some cartridges are called semi-rimmed such as .38 Super and .38 ACP. But they are not usually part of a new shooter’s loadout.

At the very bottom of the case, you will see a small circular item embedded into the base of the case. This is the primer, and it’s what ignites the propellant when struck. The primer contains a small charge and sparks when struck by a firing pin or hammer.

Topping it all off is our bullet. There are numerous bullet types, but the most common one is called ball. These bullets have a lead core and are encased inside a copper jacket.

What is a Round?

Another term that is usually interchangeable with “cartridge” is “round.” This is especially true when discussions turn to how much ammunition may be needed for a class or exercise. You will need “x” number of rounds.

The process by which a round fires is also interesting. While seated securely in the gun’s chamber, a firing pin or hammer will strike the primer in the back of the round. That causes a small spark, which in turn ignites the propellant. The propellant begins to burn and creates gas. This super-fast expanding gas builds up on the back of the bullet and launches it down the barrel. The force is enormous, and the bullet is forced into the barrel.

It is important to note that an unfired bullet will not fit down a barrel. Only through the force of being launched will it enter the barrel and then leave the gun.

Picking the Right Ammunition

As I mentioned earlier, there are a wide variety of bullets to choose from. The driving force behind this variety is application. Traditional ball ammo will do the job if you are just looking for range ammunition for a little gun time.

If you are looking for personal-protection rounds, you should consider hollow-point bullets or jacketed hollow points (JHP). The bullet on these rounds is designed with a semi-hollow tip. In some cases, this hollow space may have a small piece of plastic in it. This design allows the bullet to expand once it strikes its target. This causes a larger wound channel and has a better chance of stopping a threat.

The hollow point design allows the bullet to expand and is ideal ammunition for self-defense.

A secondary benefit of these rounds is to minimize overpenetration. The chances are high that these expanding rounds will stay within our target and not pass through and cause danger to others.

It is important to choose the correct ammo in this situation. JHPs are the gold standard for personal protection and are used by law enforcement. While ball ammo will certainly put holes in a bad guy, you run the risk of overpenetration.

Ballistic Tip ammunition is popular for hunting for a number of reasons. The polymer tip ensures accuracy, while the hollow point allows expansion.

A round that is still around in small quantities is wadcutters. These are essentially flat-faced lead bullets. They were the precursor to JHP ammo and are known to make a big hole. Technology has eclipsed this round for personal protection, but some in competition circles still use it.

In addition to these bullets, there are a variety of unique designs that companies have introduced. For example, the Syntech bullet from Federal is a polymer-coated round that is well known to shoot clean and extend the life of your barrel.

Barrel Diameter

The next item that comes up in question is caliber. This can be confusing because we hear the terms like “9mm” and “.45” without much of a frame of reference. Caliber is the term for size designations for bullets and the inside diameters of the gun barrels through which the bullets are fired.

Most of the world uses metric sizing, while the commercial market in the United States uses a U.S. standard measurement. This can be confusing, but it can be cleared up pretty easily.

Ammo runs a wide range of sizes from the small .22 LR rounds to these large and powerful .50 BMG cartridges.

The measurements in metric are almost always a “diameter to length” ratio. For example, a bullet in the caliber 9x19mm is 9mm wide and 19mm long. Standard measurement ammo is very similar and looks at the diameter of the bullet in relation to inches. For example, .45 ACP is .45 inches in diameter.

This is where shooters need to take great care in buying the right ammo for their guns. While we may just ask for 9mm, you can end up with 9mm Kurz, 9×18 Makarov, 9×19 Para., or 9×21 Largo. Your firearm will have the specific caliber you need engraved on the barrel.

Terms that sometimes follow the numbers, such as .45 ACP, generally reference a design name. ACP, for example, stands for Automatic Colt Pistol. Once again, verify the ammunition your firearm is designed to shoot. Firing the wrong ammunition can be extremely dangerous.

Gauges

Another ammo area that has many people shaking their heads is shotgun shells. Now we ditch our caliber discussions and move into gauge. Gauge is a very old measurement system and is honestly antiquated in today’s world. It is, however, the standard by which shotguns are measured.

Gauge is determined by the number of lead balls of size equal to the approximate diameter of the bore that it takes to weigh one pound. For example, it would take 12 lead balls with the same diameter as a 12-gauge shotgun bore to weigh one pound.

Common shotgun gauges are 10-gauge, 12-gauge, 16-gauge, 20-gauge, and 28-gauge. The smaller the gauge number, the larger the shotgun bore.

Another difference is in construction. A rifle or pistol cartridge’s brass case contains primer, powder, and bullet. However, the shotgun’s shotshell consists of a hull that contains the powder, shot wad, and an amount of shot.

Shotgun gauge is determined by the number of lead balls of size equal to the approximate diameter of the bore that it takes to weigh one pound.

The primer is still located at the back of the shell. There is a wide variety of shotgun ammunition to choose from. Once again, it is application-driven. Birdshot is a large number of small lead pellets that work well for bird hunting. Buckshot is a smaller number of larger lead pellets that were originally designed for hunting deer, thus “buckshot.”

Buckshot has evolved as an exceptional personal protection round as well. We also can use slugs, which are a hefty lead round. Essentially a very large lead bullet. Like our other guns, your shotgun will be marked with the ammunition it requires.

Wrap Up

Ammunition can be as interesting as the guns themselves. Like any other industry, there are leaders in this field. One, in particular, is Federal Ammunition. They have been the king of the hill for decades. Federal has also been in the business a very long time and is preparing to celebrate its 100th anniversary.

I always encourage all shooters to get the best ammo they can. A high-end manufacturer such as Federal has solid quality control and production. The ammo you buy in a zip lock bag at the gun show can be sketchy from the start. Not only can you face performance issues, but it can also be dangerous if not made correctly.

In our current situation, I encourage people to buy a decent amount of ammunition for each gun every chance they get. If kept in a cool, dry area, these rounds will last for years, if not decades.

This is just a brief look at the ammunition world. I hope you take the time to dig deeper and become an expert yourself. Then share that knowledge with others.

This article was originally published in the Personal Defense World October/November 2022 issue. Subscription is available in print and digital editions at OutdoorGroupStore.com. Or call 1-800-284-5668, or email subscriptions@athlonmediagroup.com.