How do you tell the caliber of a man?

I think one of the most daunting things when I first started looking for a gun was: what size bullet to get? At the time I figured all bullets kill just fine so it was just a matter of what gun I like. Ah, I was so young and naive back then.

As time has passed, I’ve learned that I was only half right: all bullets kill but some bullets kill better than others.

Let’s take a walk through some of the most popular bullets...

What we’re going to be talking about here is purely bullet size and the benefits/weaknesses of each. Now, there’s A LOT of sizes out there but I want to cover the ones you’re most likely to see and/or use. These are the ones that you can walk into just about any sporting goods store and buy. It should be noted that when I say stuff like “most powerful” or “least expensive” and such, I’m talking in comparison to the others on the list, not to everything that’s out there in the world.

When you talk about bullets at this high of a level, the most high level trait is “Stopping Power”. This is a relatively vague trait and somewhat controversial. What it boils down to is how many bullets does it take to drop a person. Granted, if you hit someone in the right spot it only ever takes one but in most situations you’re aiming for center mass (a.k.a. the chest, a.k.a. the largest target available). Some bullets have enough power or other traits that will cause damage to organs even if you don’t hit them. You might also hear about a term called “Hydrostatic Shock” but that’s an entire article unto itself.

I should also point out that the term “caliber” is nothing more than the size of the bullet. For most handgun rounds, the number is the diameter, in inches, of the bullet. That means that a .40 caliber bullet, for example, is .4 inches across. When you talk of caliber, you drop the decimal point, btw. People will look at you weird if you walk into a store and ask for “point forty ammo”.

Still with me? Good, now that all that is out of the way, let’s start with the runt of the litter....


.22 Caliber RoundsThough not the smallest round by far, it is the most common tiny round. It’s also sometimes called “twenty two long rifle” and “twenty two rimfire”. The rimfire term is, once again something for another article but 9 out of 10 times when you hear someone talk about a rimfire, they’re talking about a .22LR. 

Pros: Tiny, light and stupid cheap. You can get 500 of them for around $15 and carry all of them in a fanny pack or the leg pockets on your cargo shorts (you’ll look weird, mind you, but still). The recoil is almost non-existent which makes it a great starter round for someone who has never shot a gun or is uncomfortable with the noise. The low price of the bullets is also great for learning sight pictures.

Cons: Did I mention they’re tiny? These things are only a few steps up from a pellet gun round. They can kill, don’t get me wrong, but they’re mostly for killing rats, snakes and birds. They’ll kill an attacker for sure but it might take a shot or six.


.25 Caliber Rounds

Slightly larger than the .22 and slightly more powerful....though not much. There are quite a few guns that use this size but the ammo is more expensive and you’re not getting too much added benefit other than the inherent reliability that comes with center fire casings.

Pros: Slightly more stopping power than the .22 but it’s kind of like the difference between stabbing someone with an icepick or a knitting needle. Both do the job, but one will leave an ever so slightly larger hole.

Cons: Same thing as the .22, really. It’s a tiny round and I’ve yet to use a .25 caliber gun that didn’t work like crap. I’ve used a few flawless .22’s, however. I don’t know why that is.


.380 Caliber RoundsNow we’re getting into the beefy sizes. Personally, I would never use a gun with anything smaller than a .380 as my primary carry weapon. Sometimes called a “9mm Short”, it has seen a major boost in popularity recently thanks to the various “pocket pistols” that have come on the market. This is also a very controversial round. If you ever want to troll a gun forum, just go there and ask “which is better: a .380 or a 9mm?” or “Does a .380 have enough stopping power to use it as a carry?”. Watch the arguments start. It’s entertaining. 

Pros: This bullet has relatively low recoil and, at close range, good penetration. They’re a great carry weapon size, in my noobish opinion.

Cons: Gun author Massad Ayoob once said of the .380 "Some experts will say it's barely adequate, and others will say it's barely inadequate”. This is a low power round. Because of the nature of the bullet and the guns that shoot it, it’s going to be relatively useless beyond close-ish range.


9mm RoundsMy personal favorite. Also called the “9x19mm Parabellum” and the “9mm Luger”, if there was a “Goldilocks Round” this would be it. The very first gun I bought was a 9mm. They’re fun at the range. They’re good for defense. Believe it or not...or actually believe it because it’s true...the 9mm bullet is the same size as the bullet used in the .380 and the .38 Special (see below). The only difference between the three is the amount of gunpowder behind it.

Pros: This is arguably the smallest bullet that will result in the fabled “hydrostatic shock”. The rounds are inexpensive and they have very low recoil. Many, many guns use this size as well. A compact 9mm gun can be used for concealed carry. Most of the guns that use this size can hold on average 15-17 rounds in the magazine.

Cons: It’s still a relatively small round. That low recoil I mentioned in the pros section also comes with a lower amount of power behind it. It’s got some stopping power for sure but there’s nastier bullets coming up that blow it out of the to speak. Very few complaints about it otherwise.

.38 Special

.38 Special RoundsSo what makes it so special? It has a longer cartridge and more powder in said cartridge but it is a slower, heavier bullet than the 9mm. Here’s the thing: in the gun world, slower is a good thing. Think about it this way: although both would suck, would you rather be stabbed quickly by a steak knife or really slow with a spoon? Which would do more damage? The steak knife is going to make a clean cut. The spoon is going to rip and tear. The .38 special is like that spoon.

Pros: This is a nasty bullet. It’s going to hit hard. The FBI used this cartridge as its standard issue for a very long time.

Cons: This is a revolver round. You’re not going to find a semi-auto gun that fires these, as far as I know. If you’re a huge fan of revolvers then this would be a plus, I guess. I even carried a revolver for a while but that means you’re only going to have 5 or 6 rounds at a time. There’s also a hefty recoil especially in +P versions. I’ll go in depth about “+P” later but for now, it essentially means “more power”.


Remember how I said the 9mm was the “Goldilocks Round”? If that’s the case then the .40 is her big, angry, whiskey drinking sister. Ok, I have no idea what that means but bear with me. This round has got massive stopping power and a relatively small size. There are a lot of police forces that use this round as well. 

Pros: You shoot someone with this round and they will know they got hit. It maintains its track for a good long while so it has good range. Ammo is still relatively inexpensive.

Cons: If you increase the size of the round and its power, you also increase its recoil. Many people complain about the kick from this round. But the kick from the .40 is very manageable compared to...

.44 Magnum and the .357 Magnum

You know that “do you feel lucky, punk” and “go ahead, make my day” lines that everyone, including you, quote constantly (and most likely incorrectly)? Clint Eastwood (real name: Cuddles McGee) was holding a .44 Magnum revolver when he grumbled those lines. At the time it was the most powerful handgun in the world (still only second to the .500 S&W Magnum, as far as I know). These are pretty much only revolver rounds, although there’s a couple of rifles that use them. These are nothing more, however, than their close equivalents (.40 and a .38) with a massive, almost crazy amount of powder behind them.

Pros: The bullet equivalent of a sledgehammer. You hit something with this round and that something is going down. Fun fact: a .357 Magnum gun can also fire .38 special rounds but NOT visa versa.

Cons: Newton’s Law says that for every action there is an equal and opposite reaction. If a bullet is to leave the gun at a higher speed and power then the gun will react in the equivalent recoil. Long story short: the recoil is insane. This is a powerful freaking round and I would not recommend this for beginners of any sort.

.45 ACP

.45 Caliber RoundsDesigned in 1904 by Mr. John Browning himself for the famous 1911 pistol, this round has one heck of a history. This thing is a big bullet with stopping power to spare. The choice of many police officers and military personnel for years, the .45 caliber round has proven itself time and time again. I could probably do an entire article on just this bullet.

Pros: Stopping power, inexpensive and a lot of guns chamber this round. If you hit someone center mass with this bullet, they will drop. If they’re on drugs it’ll take maybe 2 shots. This is the round to stop someone with. Not much more I can say on it.

Cons: As with the Magnums, the increased stopping power means increased recoil. I can tell you from personal experience that this is not a round to hand to someone who’s never fired a gun before. One other point is that this bullet tends to start tumbling at around 75 yards which reduces its effective range quite a bit. For self defense that’s not a problem but if you love target shooting at long distances, you’re going to have to work hard with this round.

.500 S&W Magnum & .50AE

Even though these are relatively new cartridges, I’ll be referring to these as the granddaddy of all bullets. Coming in at a half and inch wide and packed with gunpowder, these babies are the most powerful shot around.

Pros: If you are holding this gun, people will run from you. There will be no surviving a center mass shot from these. Heck, the .500 is used for hunting bear. A handgun...for shooting Grizzly Bear. Fire this thing off at a shooting range and enjoy seeing everyone there duck from the sound.

Cons: The recoil from either of these rounds is like getting brofisted from God. We’re talking physically painful to shoot. Also, if you hold the .500 revolver wrong it can and will remove fingers (See Mythbusters Episode #121). I wouldn’t even hand this gun to my worst enemy to fire as their first shot. I don’t think you can comprehend the sound and force of one of these going off. Dang I want one though.

Wrapping Up

As I said, there's probably some obscure round out there that has more power than the ones I said were the most powerful and I'm sorry your particular favorite round was missed. This site, however, is a beginner's guide and someone who's just picking up a gun probably won't care about the benefits of the 7.65mm Mannlicher or the 5.7x28. 

For a more comprehensive list of caliber sizes, check out