By Mike Kneuer, Suburban Protector
Hey there, friend—
Let’s talk about something that tends to confuse a lot of people when they first get into firearms: bullet calibers. If you’ve ever found yourself standing in an ammo aisle feeling like you’re staring at a foreign language, don’t worry—you’re definitely not alone. Caliber talk can feel like a secret code at first, but I promise it’s not as complicated as it seems.
So, What Is a Caliber?
At its core, caliber refers to the diameter of the bullet—usually measured in either inches (like .45) or millimeters (like 9mm). That number tells you the size of the bullet, which impacts things like recoil, power, and how it feels to shoot.
This is the round made famous by the 1911 platform. It has serious stopping power and a loyal fan base—but also hefty recoil and usually fewer rounds in a magazine. I love shooting .45s at the range, but I usually steer new shooters toward 9mm first.
Common Calibers You’ll Hear About (and Why You’d Use Them)
Here’s a quick run-through of the most popular calibers and what they’re typically used for:
Think of it like different engine sizes in cars. A little 4-cylinder gets the job done economically, while a big V8 packs more punch. Same with bullets.
9mm
The “Goldilocks” round—just right for most people.
This is hands-down the most popular handgun caliber out there. Why? Because it’s easy to shoot, affordable, widely available, and effective. It’s what I usually recommend for new shooters, home defense, and concealed carry. I personally carry a 9mm most days—it’s that good.
.380 ACP
The “little sibling” to 9mm.
Often used in compact concealed carry pistols, .380 has low recoil, making it more comfortable to shoot. But with that comfort comes a little tradeoff in stopping power. I usually recommend .380 for those with smaller hands, weaker grip strength, or those who are more recoil-sensitive. My advice? Shoot it and see how it feels.
.45 ACP
Big, bold, and built like a tank.
.22 LR
The best “starter” round for new shooters (and squirrels).
If you’re totally new to firearms, this is where I often begin. It’s quiet, super low recoil, and dirt cheap to shoot. It’s great for learning the fundamentals, target practice, or even introducing your kids to shooting in a safe and fun way. Everyone should own a .22, in my opinion.
.40 S&W
The “in-between” caliber that’s fallen out of fashion.
This used to be the FBI’s go-to, but many agencies (and civilians) have moved back to 9mm. It has more recoil than 9mm, less capacity, and not a huge advantage in stopping power. That said, if you already own one, it’s still a solid caliber. I don’t talk people out of it—I just don’t often recommend it as a first choice.
Choosing the Right Caliber for You
Here’s my philosophy—and it’s the same thing I tell my students during training:
“The best caliber for you is the one you can shoot confidently, accurately, and consistently.”
A hit with a .22 beats a miss with a .45 every time.
So don’t get caught up in online debates or YouTube rabbit holes. Come to the range, try a few different calibers, and see what fits your hand, your skill level, and your goals. That’s the real way to find your match.
Want to Learn More? Come Shoot With Me.
At Suburban Protector, we don’t just sell you on gear—we help you become confident with your firearm, no matter your experience level. I love helping new shooters figure out what works for them and watching that “aha!” moment when things start to click.
If you’re in South Florida and looking for firearms training that’s approachable, judgment-free, and highly effective, let’s get together and make it happen. You bring your curiosity—I’ll bring the knowledge and a few different calibers to try out.
Stay safe, stay sharp,
Mike
Need help deciding what caliber is right for you?
👉 Mike@SuburbanProtector.com or 561-213-2974 to schedule a beginner-friendly session today.