Ballistic Breakdown: Comparing the Most Common Self-Defense Ammo

When it comes to concealed carry, choosing the right firearm is just half the equation. The other half? Ammunition. Whether you’re running a compact 9mm or a full-size .45 ACP, the round you load into your magazine could make all the difference if the unthinkable ever happens.

Ballistics isn’t just for lab coats and FBI charts—it’s real-world performance that should match your everyday carry (EDC) needs. Let’s break down the most common self-defense calibers in America and compare their ballistic performance in the situations that matter most.

The Top Self-Defense Calibers on the Street

Here are the top five most commonly carried self-defense handgun calibers today:

1. 9mm Luger (9x19mm)

2. .380 ACP

3. .40 S&W

4. .45 ACP

5. .357 Magnum

Each has its pros, cons, and die-hard fanbase. But we’re not here to debate feelings—we’re here to look at cold, hard ballistic data.

The Ballistic Categories That Matter

Let’s define the key metrics:

• Muzzle Velocity (fps): Speed of the bullet as it leaves the barrel

• Muzzle Energy (ft-lbs): Force the bullet delivers on impact

• Penetration (FBI Standard): Should fall between 12"–18" in ballistic gel

• Expansion (Diameter): How much the bullet mushrooms on impact

• Recoil Impulse: How much kick you’re dealing with

• Capacity Tradeoff: How many rounds you can fit in a standard-sized magazine

Now let’s line ‘em up.

1. 9mm Luger: The Jack of All Trades

• Muzzle Velocity: 1,100–1,200 fps

• Energy: 330–400 ft-lbs

• Penetration: 13"–17" (most brands hit the sweet spot)

• Expansion: 0.60–0.72 inches

• Recoil: Manageable in most pistols

• Capacity: 10–19 rounds (depending on frame size)

Why it’s popular: Modern 9mm ammo has closed the gap on .40 and .45 in stopping power while allowing higher capacity and faster follow-up shots.

Best Use: Everyday carry, home defense, and training. It’s affordable and widely available.

2. .380 ACP: Pocket Power with Compromise

• Velocity: 900–1,000 fps

• Energy: 190–220 ft-lbs

• Penetration: 9"–13" (some rounds fail to reach FBI minimum)

• Expansion: 0.50–0.60 inches

• Recoil: Very low

• Capacity: 6–10 rounds in small frames

Why people carry it: Fits in tiny guns like the Ruger LCP or SIG P238. Very easy to conceal and handle.

Drawback: Less energy and sometimes underpenetration depending on ammo brand.

Best Use: Deep concealment, backup gun. Choose premium defensive loads like Hornady Critical Defense or Federal HST Micro.

3. .40 S&W: The Middle Child with a Mean Streak

• Velocity: 950–1,200 fps

• Energy: 400–500 ft-lbs

• Penetration: 13"–16"

• Expansion: 0.65–0.75 inches

• Recoil: Snappy, especially in compact guns

• Capacity: 9–14 rounds

Why people still love it: Hits harder than 9mm, with more energy transfer. Once the darling of law enforcement.

Why it’s fading: More recoil, less capacity, and recent FBI testing shows 9mm doing the same job with fewer tradeoffs.

Best Use: If you shoot it well and don’t mind the recoil, it’s a solid performer.

4. .45 ACP: Big, Slow, and Proud

• Velocity: 830–950 fps

• Energy: 350–450 ft-lbs

• Penetration: 12"–14"

• Expansion: 0.70–0.80 inches

• Recoil: Soft push but still stout

• Capacity: 7–10 rounds

Why folks swear by it: It’s a big bullet. It expands well and has a legendary track record.

Downside: Lower capacity, bigger guns, slower follow-up shots.

Best Use: Full-size pistols and home defense where concealment isn’t critical.

5. .357 Magnum: The Thunderstick

• Velocity: 1,200–1,500 fps (depending on barrel length)

• Energy: 500–700+ ft-lbs

• Penetration: 14"–20" (watch for over-penetration!)

• Expansion: 0.60–0.75 inches

• Recoil: Heavy in snubbies, manageable in full-size

• Capacity: 5–7 rounds in revolvers

Why it’s still carried: Devastating terminal performance, especially with 125gr JHP loads.

The flip side: Brutal recoil in small guns, loud, and flash-heavy. Also: revolver reload times are slow.

Best Use: Woods carry, backup gun, and self-defense if you’re trained and comfortable.

Ammo Comparison Table

Final Thoughts: Which Should You Carry?

There’s no one-size-fits-all answer—what matters most is:

• Can you shoot it accurately under stress?

• Can you control the recoil for follow-up shots?

• Does the ammo penetrate and expand reliably?

• Does your platform (gun size, capacity) fit your lifestyle?

If you’re carrying for defense, invest in high-quality defensive loads from trusted names like Federal HST, Speer Gold Dot, Hornady Critical Defense, and Winchester Ranger-T. Test them in your firearm.

Our Pick for Most Balanced Option: 9mm

Modern 9mm defensive rounds perform just as well (if not better) than .40 or .45—with more capacity and less recoil. That’s why it's dominating the market today—from concealed carriers to law enforcement and military.

Bonus Tip: Regardless of caliber, shot placement wins fights. A well-placed 9mm is worth ten missed .45s. Train regularly, carry smart, and stay ready.