Handgun Calibers: Uncover Bullet Size, Types, and More

Before you purchase a handgun, you should understand all the handgun calibers available. There are plenty of options to consider. Each caliber suits different uses and activities. For instance, you may choose the 9mm for everyday carry or self-defense. Alternatively, you could opt for the .44 Magnum for hunting bigger game.

But what exactly goes into choosing a handgun caliber? Factors like ammunition cost per round, terminal ballistics, or recoil are popular considerations to start with. Keep reading this guide to learn all about handgun calibers to choose from for your specific shooting needs.

Caliber refers to the measurement of a bullet's diameter — typically in inches or millimeters. It denotes the bullet's size and does not include the cartridge casing. Understanding caliber is essential when shopping for ammunition to ensure compatibility with your firearm.

Popular handgun calibers include .40 S&W, .380, .32 ACP, .45 ACP, 9mm, and 10mm. These calibers serve distinct purposes and features, including:

• The .40 S&W derives from the 10mm — with less powder in the case to manage better-felt recoil. This caliber is more applicable for self-defense.

• If you want a round that is easier to conceal and handle and priced cheaper than other options, then the .380 ACP is an excellent choice!

• The .32 ACP is suitable for pocket guns and self-defense.

• The .45 ACP and 9mm are often discussed as top choices for concealed carry and home defense.

• While you CAN use the 10mm for self-defense, this caliber is almost exclusively used for hunting.

Not all handgun calibers are created equal. They have a variety of recoil, stopping power, and other features. Learn the key terms of bullet weight, diameter, velocity, energy, and penetration depth so you can make the best decision when choosing ammo caliber and a firearm with a specific caliber.

• Bullet Weight: Higher grain (heavier) bullets offer better wind resistance and deliver more energy to the target, but recoil from the firearm is typically greater. In contrast, lower grain (lighter) bullets achieve higher speeds and a longer range with less recoil, depending on the firearm.

• Bullet Diameter: This measurement refers to the width across the center of the bullet, not including the casing. This is also known as the ‘caliber.’

• Fragmentation: Frangible bullets are lighter because of the structure and materials required to support fragmentation. In general, bullets are either designed to retain shape (FMJ), expand (hollow point), or fragment.

• Velocity: Velocity refers to the speed at which a bullet travels after being discharged from the handgun. Bullets with higher velocity offer a flatter trajectory, which is advantageous for achieving longer distances and more accurate shots.

• Energy: Muzzle energy measures the kinetic energy of a bullet as it exits the firearm's muzzle. It’s also an indicator of its potential power after it leaves the barrel.

• Penetration Depth: Handgun calibers vary in penetration. Optimal penetration is between 12-18” per the universal standard FBI test protocol. Deeper penetration can increase effectiveness, but shallower penetration reduces the risk of damaging surroundings or harming bystanders.

Centerfire and rimfire ammunition represent two distinct primer-ignited cartridge designs. In centerfire ammunition, the primer is located in the middle of the cartridge, while rimfire ammunition houses the primer in the rim.

Hollow point and full metal jacket (FMJ) bullets are the two most popular types of bullets for handguns. Hollow point ammunition expands upon impact to increase the round’s damage potential. Conversely, full metal jacket bullets have a lead core encased in a harder metal shell.

A less popular bullet is the expanding full metal jacket (EFMJ). EFMJ is an alternative to hollow point as it expands upon impact when hitting any surface. It contains a polymer insert and pre-scored jacket. This design causes a wider cavity and reduces penetration without fragmentation. In contrast, fragmenting ammo is designed for deeper penetration and fragmentation in fluid.

With so many caliber sizes for handguns available, it can be tricky to narrow down the right caliber for your needs. Consider the following factors to pinpoint the right caliber for you.

• Intended Use: Will you use your handgun caliber for self-defense, concealed carry, or hunting? The 9mm is great for self-defense while the .44 Magnum is ideal for hunting large game.

• Your Experience: Are you a beginner or more experienced? A .45 ACP is better suited for more advanced shooters due to its powerful recoil. Stick with caliber options like the 9mm and .38 Special if you’re a beginner.

• Recoil: This affects your ability to handle the pistol, as well as accuracy. Your performance can be negatively affected if the recoil is too strong.

• Ballistic Performance: Bullet penetration between 12-18” is optimal. This causes an effective strike while minimizing risk to innocent bystanders. Certain bullets increase damage, such as hollow points that expand.

• Magazine Capacity: If you’re using your pistol for self-defense, pay attention to how many rounds it holds. You might be better off with a magazine capacity of 17 compared to 10 if you want a handgun for self-defense.

• Cost: The .22 LR offers the cheapest ammunition. Consider the price of ammo if you’re a beginner and want to practice shooting.

The 9mm is one of the most popular calibers. A full-size 9mm handgun has a 17-round magazine capacity. Firearms that use this caliber tend to have lighter recoil and offer faster follow-up speed between shots.

The .38 Special and the .380 ACP are not the same type of bullet. The .38 special is used in revolvers while the .380 ACP is used in semi-automatic pistols.

Recoil is more closely related to the size of the firearm. The Sig Sauer P365 is a micro-compact pistol. It’s very snappy! However, a GLOCK 34 (G34) is a full-size long-slide handgun with a gentler kickback. Smaller-framed pistols usually don’t have the mass to absorb recoil as much as larger ones.

Handgun calibers — like the 9mm — vary in power, which can affect recoil. However, increasing the size of your handgun generally reduces the kickback you experience when shooting.

Ready to take the perfect handgun home? At Academy, you can shop for handguns by caliber and enjoy top brands like Glock and Sig Sauer. From self-defense to hunting — we’ve got the right caliber for your shooting needs. Don't forget to replenish your ammunition supply for more target shooting practice.