A major consideration for your first firearm purchase revolves around the caliber you decide on. Caliber is one of the most important choices you need to make. Some first time firearms buyers may think “A bullet is a bullet. Does caliber really matter that much?” The answer is yes. Your firearm’s caliber plays a big role in the main purpose of the gun (target shooting, home defense, hunting, etc.). Second, caliber significantly impacts the shooting experience (recoil, overall gun size and weight, etc.). So, let’s dive into caliber options a bit more, with a focus on handguns. We’ll write more about rifle and shotgun ammunition in another article.
As with most articles on this site, this one is geared for first-time gun owners. So, I won’t go into minute detail about calibers. Instead, I’ll give you an overview, so you understand the basics of firearm calibers and why they matter.
When it comes to handguns, you have over 12 or so fairly common calibers to choose from. There are a few more, but they aren’t as common. This list already includes a few outliers, so it should cover pretty much all the calibers you will want to consider. But, how do you choose?
First off, let’s define what caliber means. At its most basic, a caliber is a measurement of the bullet’s diameter, not including the casing. Similarly, it can also refer to the internal diameters of a firearm’s barrel. But, diameter isn’t always measured in exactly the same way and doesn’t always use the same system of measurement. This is why you’ll see things like a .22 Long Rifle vs. a 9MM round.
Here’s a quick breakdown of 12 handgun calibers, ordered by actual diameter and the use cases each tends to be designed for.
| Caliber | Common Uses |
|---|---|
| .22 Long Rifle | Target shooting, small game hunting |
| .25 ACP | Concealed carry |
| .32 ACP | Concealed carry |
| .380 Auto | Concealed carry, self-defense |
| 9MM | Self-defense, concealed carry, target shooting |
| .38 Special | Concealed carry, self-defense |
| .357 Magnum | Hunting, self-defense |
| .40 S&W | Self-defense, law enforcement carry |
| 10MM | Self-defense, hunting |
| .45 ACP | Self-defense, law enforcement carry |
| .44 Magnum | Hunting, self-defense |
| .50 AE | Hunting |
What you’ll notice is that as the size of the round increases, the use cases tend to start including self-defense, law enforcement uses, and hunting. There’s more to determining which round is the most powerful, but size is a good place to start. So, if your purpose is to have a gun to carry when you go hiking or hunting, you’re likely looking at 10MM and larger as the most suitable calibers. This doesn’t mean a 9MM isn’t sufficient, but if you’re in bear country, a larger round is more likely to help you in a worst case situation.
However, it’s more likely that you’re looking for either a personal defense weapon or even a concealed carry handgun. In those cases, you can see that slightly smaller calibers may be more in your wheelhouse.
So, what’s the best caliber for a first-timer?
I encourage you to really consider your purpose for buying your first gun. But, if it falls into the concealed carry or personal defense categories, I think a 9MM is a great place to start. It’s not the biggest round, but also not the smallest. It is the most commonly sold round these days. This means ammunition is usually fairly easy to find (it definitely wasn’t a few years ago, though) and you have a huge range of firearms to choose from, larger than any other caliber. 9MM rounds are used in guns ranging from micro-compact guns designed for the easiest concealed carry, up through full-size handguns designed for competition or home defense.