Calibers-The Most Common Sizes You Should Know About

For those of you hunters or military professionals, or no matter the connection to guns, you know that having the right ammunition is what makes you a good or a poor shooter.

Buying the gun isn’t enough. You need to get your bits and bobs about the ammunition, types, and sizes of bullets and everything related. The caliber is another thing to learn about, so keep scrolling for the details.

How to select the caliber?

If you’re a newbie, you should know that it’s fundamental to select the appropriate caliber size. Here are aspects to consider when choosing the caliber of your bullets:

  • Bullet weight- typically, it’s measured in grains, with 7,000 for a pound. The stopping power is the highest level, and you need to know the number of bullets for hitting a target.
  • Energy- it relates to the power of every round
  • Price point- the price for a single round
  • Velocity- says about the accurate speed of the bullet in feet/sec

What are the most common bullet calibers nowadays?

There are myriads of bullet calibers, but you’re not going to use nor meet most of them. You’re only going to use a couple of them throughout your entire life.

It’s because you’re using a gun for a specific reason. Some go hunting, others like sporting, and there’s also the category using weapons for self-defense.

The most common calibers win the popularity contest for several reasons. And the chances are that you’re going to get the very first type that fits your needs, nine times out of ten.

Without any further ado, let’s take a look at the most popular calibers out there:


When it comes to the number of units sold until now, the .22 LR is the most popular type out there. It’s a small round that comes with low recoil output, and you can use it for both handguns and rifles. However, the .22 rifle presents a rimfire and not a centerfire, because the firing pin doesn’t hit the center, but the rim of the case.

Many like the .22 rifle for its speed and compact profile, which allow straightforward use. It’s a reliable option for a beginner that wants an easy to use caliber, while also ensuring the power one needs for shooting.

It’s a reliable option for recreational shooting, firearms training, and even small game hunting, which explains why it’s sold in bulk. There are multiple versions for the loads, from subsonic (target rounds) to high speed (1200 to 1310ft) and ultra/hypervelocity (more than 1400ft).

Since the subsonic rounds are small, it makes sense that they’re also slow. Typically, you find them fitted with extra-heavy bullets, ranging from 46 to 61 grain.

The caliber is dependable for firing small targets (rats, birds, and snakes) and target shooting. If used on human targets, it can get very damaging and even be lethal. It’s because the smaller can bounce inside the human body, tearing ligaments and organs. The caliber comes with 30-40 grains of bullet weight, with 1200-1600ft/s speed and 140-160 Joules for energy. Its low price seals the deal, especially for the newbies.


ACP comes from Automatic Colt Pistol, and the centerfire pistol caliber has straight walls and semi-rims. It was created for the blowback pistol that didn’t come with a breech locking mechanism.

The caliber is more significant than .22, and stronger too since it’s supposed to resemble the .22. However, there aren’t many guns that use the caliber, also because it’s quite expensive.

The most significant advantage is that it comes with a centerfire casing, which makes it highly dependable. The .25 ACP also presents a higher stopping power than the .22. The caliber is low powered and short-ranged, which makes it safer when used on humans.

The .25ACP is compact and lightweight, and a viable choice in personal home defense handguns thanks to its centerfire case design.


The .45ACP was created for the 1911 pistol and are one of the cartridges impressing with their history. It’s a big caliber that presents impressive stopping power. For many years now, the .45ACP has been the most used option for police officers and military personnel.

Even if you use the .45ACP with 230grains large bullet, the recoil will be moderate. Be aware that you do need some skills for shooting it right, which is why the newbies shouldn’t get it at first. The stopping power is one of the main benefits of .45ACP.

The .45ACP is a reliable model for the practice and self-defense, with its affordable price sealing the deal for the professionals and experts.


If big bullet sizes are your thing, the 380ACP is one to add to your collection. Also known as the 9mm short, the caliber has become popular over the last years.

It presents a low recoil and can penetrate deeply when short at a close range. Its power round is rather small, though, which is why it’s better that you shot at close range.

The main pet peeve is that it has a significant carry size. It’s compact and lightweight, which makes it easier for carrying. It has lesser stopping power and quite a short-range.

It’s one of the most popular options within the self-defense cartridges for anyone liking the lightweight pistols with recoil.

.30 carbine

Even if the.30 Carbine isn’t standard anymore, and it does have a fascinating history. It was the caliber in M1 carbines during World War 2 and quite popular until the Korean War.

The .30 was the first option for personal defense back in the days, and combats liked it since it didn’t alter their jobs and duties.

It’s a lightweight and handy caliber that weighs 5 pounds (give or take). It comes with non-corrosive primers, and it’s still one of the greatest calibers. It features an economical plinker, for faster and effortless loading.

It reaches a 2000ft/s speed and only weighs 110grains.


Some name it the Three Hundred Blackout, and it has made it to the rifle world only some while ago. It’s supposed to introduce the.30 caliber round into the AR universe.

It can ensure incredible control of many modern magazines, and its flexibility and power are the selling points. You may improve its elasticity by using adjustable gas blocks, with the subsonic bullet being able to over-penetrate and expand under.

It’s a shooting range of firearms that you may load fast after some practice. It’s highly dependable for self-defense purposes, has a 2200ft/s speed, and 125grains for weight.


The official name is 9mm Luger or the 9x9mm Parabellum so that you can tell it apart from all the other 9mm rounds. If you like shooting at close range and are interested in self-defense, the 9mm is an excellent option for you.

It’s the standard bullet for NATO countries and the majority of police forces around the world. It’s mild in shooting, and it weighs between 115 and 147 grains. The stopping power depends on the type of bullet you use.

The bullets have low recoil and are affordable. You may use them for various guns, with most guns being able to hold 15 to 17 rounds. The 9mm is also a solid choice for concealed carry.


It’s the civilian alternative of the cartridge used by the United State’s military, which is 7.62. It looks better, and it’s also larger than the NATO round.

The recoil and the higher price may be the main reasons for which it’s not the most popular caliber at the moment — many like it for its knockdown power and extended range.

The .30b is the ideal option for snipers, with speed ranging from 2,600 to 2,700 ft/s. The bullet weighs between 147 and 175 grains, whereas the price is 75 cents per round.

40 S&W

The .40S&W was created for the FBI, functioning as a compact 10mm cartridge. It’s quite a popular choice with law enforcement agencies in Canada, Australia, and the United States. It’s an affordable cartridge that has more kick than other handgun cartridges out there.

But the low price isn’t the only good thing about this one. It’s a lightweight option, with weight ranging going from 155 to 180 grains.

Despite the positive aspects, people in the FBI still prefer the 9mm cartridge since it allows faster and more accurate shooting. If we’re only talking about the energy and more comfortable to manage recoil, we still consider the 40 S&W a better option.

Tests revealed that the 40S&W is one of the best (if not the ideal!) cartridges for personal defense and law enforcement.

Instead of conclusion-  a word on the less common bullet calibers!

The variety of calibers is overwhelming, especially for a newbie. Here are some words about the less common calibers you can choose from:

  • .300 blackout- it’s created for ensuring the fantastic performance of the larger.30 caliber AK 7.62x39mm round, even it was developed for the AR 15.
  • .30 Carbine- it’s lightweight that many militaries used it, especially during the Korean War. The typical bullet has 110grain weight.
  • .357 Magnum- it’s an improvement of the .38, and it’s created for revolvers. The stopping power is the most critical advantage, which compensates for the somewhat decent recoil. It’s around 80 cents.
  • The 10mm- it’s a sturdy caliber, so many cannot handle it. It’s the main reason for which it was downgraded to the .40S&W and 9mm later on. However, the hard recoil and the fantastic stopping power are its fundamental features.