What to Consider when Choosing a Handgun Caliber?

New gunners may be overwhelmed by different calibers of pistols on the market. Last week, we introduced the most popular handgun calibers in the world. In addition to the brand and the reputation, how should you choose the most suitable pistol among so many calibers of different sizes and power? Let’s take a look at the following factors.

Rimfire vs Centerfire

Rimfire refers to ammunition in which the primer is ignited by the firing pin crushing the base’s rim. This requires extremely thin cases and limits rimfire cartridge to be low-pressure loads. The common rimfire cartridge includes .22 LR, while other commonly seen calibers, like 9mm, .38 Special, .45 ACP, .357 Magnum, etc., are centerfire ammunition, meaning the primer is located at the center of the case head.

Compared with the centerfire cartridge, rimfire is inexpensive and less reliable. That also explains why .22 LR is not suitable for self-defense.

Performance and Recoil

Bullet weight and velocity have a large impact on the energy of the hit target and larger or faster bullets also create more recoil you feel. It is especially true in lighter pistols since heavier ones absorb more felt recoil.

Theoretically, calibers with heavy and fast bullets seem ideal, but it can actually have a significantly negative impact on your shooting ability. Greater recoil will reduce accuracy and take longer time to get back into target between shots.

That is to say, if you cannot hit the target with the given caliber, the ballistic performance matters nothing.

Ballistic Performance

At present, ballistic gel tests, a standard testing replacement for living tissues, are the best way to test the ballistic performance of different calibers or the same calibers with different cartridge loads.

FBI recommends in the ballistic gel tests that the bullet should penetrate a range of 12 – 18 inches since this range will effectively wound human beings. The bullet penetration of less than 12 inches may come short of vital organs, while more than 18 inches is inclined to penetrate the target and run the risk of hitting innocent onlookers.

Full metal jacket (FMJ) and hollow point bullets (HP, JHP) are two major bullet types. Full metal jacket bullets have a soft core completely encased in harder metal, whereas hollow point bullets are hollow at the tip of the projectile. The cheaper FMJ loads are usually used for target shooting and shooting practice, while JHP are used for self-defense. Both are designed to expand the diameter of the projectile when hitting a target, causing greater damage areas and increasing the fatalities.

According to the ammo retailer Lucky Gunner’s tests, the famous 9mm rounds expand the diameter of 0.69” – 0.74” when impacting a target, the .40 S&W cartridges expand to 0.7” – 0.82”, and the .45 ACP loads can expand to an outlier as great as 1.0”. Worth to mention, expanded diameter will also determine the stopping power of bullets.

Your Shooting Ability

FBI’s ballistic gel testing shows that most tested participants performed better with 9mm calibers. Although modern hollow points reduced the gap in penetration and bullet diameter with larger calibers, most shooters tend to choose 9mm calibers for self defense.

Nevertheless, if you are capable of the speed and accuracy of .40 S&W or .45 ACP, you can certainly consider these calibers for self-defense. See how different calibers feel when practicing at the range and consider testing the time spent with a timer.

Stopping Power

Stopping power, or knockdown power, measures how effectively a bullet can reach a major blood-supply organ or threat to the central nervous system and destroy it. Are there any differences in stopping power among different calibers by one shot?

The internet has some surprising accounts about the stopping power, which usually involves a near point blank range shot and precision round placement. Knowing the stopping power can help you decide which calibers are suitable for self-defense, hunting, or shooting training.


Most pistols are available in various calibers. Once you select a pistol, try to find a pistol that has controls within easy reach and shoot it with different calibers. A Glock 26 with 9mm caliber may be firing uncomfortable for some shooters, whereas a Glock 20 with 10mm cartridge may be turned out comfortable in larger hands.


Some calibers are easier to find and more sufficient in supply than others. A few years ago when the ammo is in great shortage, everything dry up and the common calibers run out as fast as the most popular 9mm caliber while the odd rounds disappeared on shelves much more slowly than the most common calibers.

Magazine Capacity

However, the larger bullets and cartridges are, the fewer the rounds can fit in magazines of similar sizes. For example, the magazine of 9mm Glock 17 holds 17 rounds, whereas that of the .45 ACP Glock 21 only holds 13 rounds.

Source: bulkcheapammo.com

The magazine capacity is meaningful because you may need to take several shots to hit an attacker or you will miss shots in a high-pressure environment. And, the magazine capacity matters much when comparing a compact and subcompact handguns.

It doesn’t matter even if you are comfortable with larger bullets. With Cytac Universal Double Magazine Pouch (Item No.: CY-MPU), you can carry more spare ammunition with you for self-defense, shooting training, shooting competition, combat, hunting, law enforcement, or other mission requirements. It perfectly fits 9mm, .40, and .45 caliber single or double stack magazines and can be attached onto 10 different carrying platforms like Paddle, belt loop, MOLLE, low ride belt loop, drop leg platform, shoulder harness, etc.

Cytac Universal Double Magazine Pouch (Item No.: CY-MPU)

The mil-spec polymer making is wear resistant, lightweight, waterproof, and easy to clean with a piece of cloth. Besides, the good elasticity of polymer allows you to adjust the space tension easily – only bare hand adjustment by tightening or loosening the front screws to perfect hold and ensure smooth draw of your magazines.

Any concerns or queries, please feel free to contact our sales team.

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Bullet Energy

Although bullet energy of a round is over-emphasized, the bullet energy for pistols is very low and sometimes has something to do with mentality. For instances, knockdown power is a controversial term born in Hollywood action movie scenes. However, people shot by a .22 LR in non-vital organs will fall down because they thought of the exaggerated scenes in action movies.

Bullet Weight

How does weights affect the bullet performance? Generally, lighter bullets have higher velocities than the heavier ones. Thus, over less than 100 yards short distances, the lighter bullets have flatter trajectories. When shooting a soft target, lighter bullets have less resistance to lose energy than the heavier ones. However, an extremely light bullets can be stopped easily by heavy clothing.

Light 9mm bullet:   100 grains Heavy 9mm bullet:   147 grains
Light .40 bullet:        135 grains Heavy .40 bullet:        180 grains
Light .45 bullet:        165 grains Heavy .45 bullet:        230 grains

Cost Per Round

As mentioned above, hollow point bullets are best for self-defense and more cost-effective brass cased full metal jackets are optimal for target shooting and target practice. However, when buying the most inexpensive FMJ ammo for practice, distinct difference is between 9mm and less popular calibers. If you are just an shooting amateur, .22 LR saves you money while giving you better experience.


What do you use your pistol for? What you need and how you use the pistol is also a crucial factor when choosing a caliber. Many calibers suitable for self-defense against human beings may not be optimal for safeguarding yourself from large wild animals while climbing or hunting. So, ensure a caliber is powerful enough for your needs. If you want to shoot a large caliber against a bear, practice more and get more comfortable with the handgun.

Permanent Cavity

Permanent cavity is the void created on a living tissue when bullets penetrate through. The larger the permanent cavity is, the greater chance the vital organs or central nervous system will get destroyed. To some extent, the larger the permanent cavity, the greater the penetration and bullet energy of a caliber.


Hopefully, now you are well on your way to select the best pistol calibers after reading this guide. Take your time, consider your demands, and make a deliberate decision rather than being pushed by salesmen.