Stefan Ganahl (ICH) [Public domain], via Wikimedia Commons
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The Most Common Bullet Sizes And What They're Good For
Stefan Ganahl (ICH) [Public domain], via Wikimedia Commons
There are so many bullet sizes! We call them “calibers,” except for shotguns, which are referred to as “gauge” or “bore.” Each is different and – just as with anything else – each has certain attributes that are beneficial for certain purposes and its own drawbacks when the same caliber of cartridge is used for a different purpose.

Now, how bullet caliber is determined is usually the diameter of the bullet (meaning the projectile at the end, the thing that goes out the barrel when the gun goes bang) or, in the case of metric rounds from one of them communist countries, the diameter of the bullet and the length of the case. In days gone by, the measurement was gotten from the diameter of the neck or base of the cartridge.

anatomy of a bullet

So, 9x19mm uses a 0.355-in (9mm) diameter projectile (bullet), and the case is a hair over 19mm long. Ergo, the 9x19mm cartridge

The .38 Special, created back when ammo makers measured the neck, uses a .357-in diameter projectile but the cartridge case is .378 inches in diameter at the neck and base of the case. The .357 Magnum cartridge is named for the .357-in diameter projectile.

Rifle cartridges largely have the same conventions; metric or English measurement of the diameter of the projectile. Some, such as 7x57mm Mauser, use the European measurement of “bullet diameter” x “case length.”

Gauge or bore of a shotgun is measured in a wholly funkier manner. How those are measured is how many lead spheres the same diameter of the barrel would make 1 lb of lead. In the case of 12 gauge, twelve of them. In the case of 20, twenty and so on. The only exception is .410 bore, which is the diameter of a slug fired from a .410 bore shell. The shell is actually 0.455 inches in diameter, which makes it a .45 caliber shotgun.

So, now you can look at a cartridge name and get an idea as to how big it is. Let’s go over some common cartridge sizes and what they’re good for.

The Most Common Bullet Sizes And What They're Good For
Malis [Public domain], via Wikimedia Commons
First is .22 Long Rifle. This is a .22-caliber rimfire round with a tiny case, chambered in pistols and rifles. This little pipsqueak round is good for target shooting, with almost no recoil and decent accuracy. It’s also good for small game hunting.

While it has been successfully used for self-defense (actually, more people die from .22LR wounds than any other caliber, but that’s just because way more people are shot with one than any other caliber) no one in their right mind would recommend you do. It’s also ridiculously cheap.

The Most Common Bullet Sizes And What They're Good For
Ryan D. Larson [Public domain], via Wikimedia Commons
The smallest of the medium bore handgun rounds that most people consider for self-defense these days is .380 Auto, also known as .380 ACP and 7mm Browning. Other small calibers such as .25 ACP and .32 ACP have generally been considered too under-powered to stay popular. Not so with .380.

While .380 ACP is lacking in almost every category compared to 9mm, it offers just enough velocity and energy to be useful for self-defense. Its small dimensions and low recoil make it popular for carrying in micro pistols.

The Most Common Bullet Sizes And What They're Good For
Chris1287 [CC0], via Wikimedia Commons
Now we come to 9mm, AKA 9mm Luger, 9mm Parabellum and 9x19mm. Velocity and muzzle energy (1000+ feet per second, 300+ ft-lbs) is sufficient for good penetration, good terminal performance with quality expanding ammunition, and the recoil is light enough for almost any shooter to tolerate it, even in subcompact rounds. It’s the standard caliber for NATO and most police department handguns for those reasons, namely a balance of power and ease of shooting.

While light on alleged stopping power, 9mm is considered the bare minimum for self-defense rounds. The FBI famously poo-pooed the 9mm due to failure to stop bad guys (such as in the 1986 Miami shootout) but it’s come a long way since then and modern ammunition has made it more than just adequate. It’s now the agency’s standard issue.

The Most Common Bullet Sizes And What They're Good For
.38 special, (note the different bullet types) Derek280 [Public domain], via Wikimedia Commons
That said, the longest-serving personal defense and target round is .38 Special, devised by Smith & Wesson at the end of the 19th century. It’s a relative slow poke, rarely exceeding 900 feet per second and 300 ft-lbs of muzzle energy except for hot loads.

However, it’s highly accurate and laughably easy to shoot with a medium-frame revolver. Appropriate ammunition selection makes it very viable for self-defense, particularly when using hollow points. These attributes made it the default police round from the McKinley administration well into the 1990s.

The Most Common Bullet Sizes And What They're Good For
.357 left, 9mm right Rude at Slovenian Wikipedia [Public domain], via Wikimedia Commons
The .38 Special was sometimes criticized for a relative lack of “stopping power” (for lack of a better term; there’s no such thing short of an elephant gun) and so Elmer Keith and a few other wildcatters tinkered with the load.

What they created was the .357 Magnum. A 158-grain semi-wadcutter bullet in .38 travels at a slow-ish 800ish fps. The .357 Magnum dials it up to over 1200 fps.

Good for target shooting, exceedingly effective at self-defense (a great many police officers carried it) and also decent for handgun hunting of small(er) game, it’s one of the great all-arounders. The .357 round, however, best shot from medium-frame revolvers, as recoil in a smaller gun is almost irredeemably punishing.

The Most Common Bullet Sizes And What They're Good For
Derek280 [Public domain], via Wikimedia Commons
Another common handgun caliber is .45 ACP. Short for Automatic Colt Pistol, this round is the same bullet loaded in standard .45 Colt revolver rounds stuffed in a shorter, rimless case for use in semi-automatics. It was invented by John Moses Browning for the finest pistol known to man: Colt’s Model 1911.

The .45 ACP is very accurate and has decent-ish energy on impact. It’s great for target shooting and competition where the power factor matters and is a proven self-defense round. It isn’t shockingly powerful, though; it’s just big with plenty of bullet weight. Don’t be fooled by caliber junkies in the comments; it’s barely any more effective at self-defense than 9mm. However, if you insist on a big bullet, it’s the easiest of the big boy calibers to shoot.

Now onto rifles. Today’s rifle shooter is frequently a tactical junkie, even though they probably have an office job. Ergo, the more common calibers and bullet sizes of yesteryear (long-action rounds like .270 Winchester, 7mm Remington Magnum and the best cartridge yet invented by man, .30-06) are almost unknown to them.

The Most Common Bullet Sizes And What They're Good For
TSgt Michael Holzworth [Public domain], via Wikimedia Commons
Instead, the big deal is .223 Remington and its slightly hotter NATO counterpart, 5.56mm NATO. This is the standard round chambered in AR-15 pattern rifles. The .223 offers much more velocity than .22 LR (over 3,000 fps in some loadings) and more muzzle energy, but is still – make no mistake – a tabby among the tigers, so to speak.

The militaries of the world use it because it’s accurate and effective on hostile personnel out to 300 meters or so, but also because it’s cheap and easy to shoot.

In the civilian realm, it’s great for target shooting, varmint hunting and also dealing with small four-legged pests (coyotes, for instance) but is a piss-poor hunting round (at best) for anything larger. It’s effective for self-defense, but load selection is critical as over-penetration (bullet going through the bad guy, the wall behind them, and into your neighbor’s house) is a serious concern here.

The Most Common Bullet Sizes And What They're Good For
Malis [Public domain], via Wikimedia Commons
Another very common rifle round is the 7.62x39mm. That’s the standard ammunition of the AK-47 platform. Some iconoclasts prefer the AK over the AR/M16.

The 7.62mm round is broadly equivalent to the .30-30 Winchester in terms of muzzle energy, trajectory and velocity, carrying more “oomph” than .223 but at the cost of slightly more recoil.

It’s decent for hunting at short range (just like .30-30) and you can shoot a lot of cheap surplus ammo for not a heck of a lot of money. It’s good for personal protection against two-legged critters; a whole lot of people are dead from being on the wrong end of an AK. However, load selection (expanding or frangible rounds are a must) is likewise critical.

The Most Common Bullet Sizes And What They're Good For
own work [Public domain], via Wikimedia Commons
The .308 Winchester – and its slightly less-powerful globalist counterpart, 7.62x51mm NATO – is currently the baseline for medium-bore, long-range rounds. It’s exceedingly accurate, and provides plenty of power for everything short of the great bears.

This round has longer legs, with flatter trajectory and plenty of retained energy out to about 600 yards for both hostile personnel and critters you want to put in your freezer.

While not as powerful as other .30-caliber rounds that use the same bullet size (.30-06, .300 Winchester Magnum) it’s still one of the best hunting rounds for North America and beyond for medium game. It’s also excellent for long-range target shooting, but with much more recoil than the previous two rounds. There’s also a lot of surplus ammo to shoot if you want to just burn through it…but the good stuff will start setting you back a bit.

So, those are some of the most common bullet sizes and calibers and the basics about them. There are hundreds more out there and plenty more to know, of course, but this is the Reader’s Digest version. Think I missed a few that merited some discussion? Sound off in the comments!

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  1. Recommend an article on how a cartridges name doesn’t always correlate to the actual diameter of the bullet. Go nuts with how .38 and .357 are actually the same bullet diameter, but back in the day some cartridges had lead rounds that were wider past the casemouth to be the same diameter of the case mouth. Or how marketing plays into naming a cartridge, such as .300 BLK when it’s the same diameter as a .308 Win.

  2. What they’re good for: 22 LR., Learning /recreation / preserving humility. .45 ACP, Serious social interactions. .38 Spl. +P, adequate back up for the .45. .223, (5.56X45), the wine of the country, even if it’s a little watery. .308, (7.62X51), about three city blocks or if they’re hiding behind a tree. .30RS, (7.62X39), there are just SO many AK and SKS out there. 12 gauge, the FINAL argument. .410, see .22 LR. Everything else is either market driven ego gratification, nostalgia or a three day wonder on the forth day…Let the hate begin.-30-

    • The .357, .41 and .44 Magnum were and are boutique rounds. E.K. knew his stuff and had the attention of the right people at the right time. These are all excellent for their intended purposes, so are the .38 Super +P, the .40 S&W. It begs the question, is their intended purpose to be useful or are they nothing but the marketing departments answers to unasked and unnecessary questions. -30-

      • The .44 and .45 share the same bullet practically. I would say the .357 mag is heading into boutique status these days.

        • Mmmm… I’m afraid they don’t.

          The .44 Special, .44 Magnum, et al use a 0.429″ bullet. The .45 uses either 0.451 (.45 ACP), 0.452 (later .45 Colt) or 0.454 (.45 Schofeld) bullet diameter, depending upon which .45 we’re talking about.

        • Somebody needs to define ’boutique’ for me. A quick check on Midway reveals there’s 51 varieties of .357 magnum ammunition available there. That’s more than everything BUT 9mm, .38 special and .45acp. You’ve got Colt and Kimber recently branching into .357 revolvers and Ruger has a much wider variety available than ever. Seems to me like the cartridge is on the upswing. I’m guessing that word doesn’t mean what I think it means.

        • Let’s not forget the .44 S&W Special. About the same ballistics as .45 ACP (neglible difference) and the recoil, to me, is almost a gentle, yet authoritative, shove.

      • The .357 magnum did stuff that the other rounds afterwards strived to imitate esp in semi auto. It’s perhaps one of the most versatile rounds ever made and had decades of experience being a primary round for LE. You can shoot damn near anything from a squirrel to a bear with it counting .38 Specials.

        While it may not be in such prevalence now the round is hardly a novelty and has a long and distinguished history. That said it’s also hard to track how many rounds are shot in .357 mag chambered guns because people shoot .38 Special from them often too.

  3. Minor nit-picks but the original and still full power loads in .357 will launch a 158gr bullet out of a 6″ revolver at 1500fps and the 7.62×39 is significantly weaker than a .30-30.

    • Not a minor nit-pick. Data presented has to be accurate. Someone will read this one article and espouse it’s legitimacy as gospel for years.

      • It never ceases to amaze me the number of gun writers who don’t know that the Federal/Remington/Winchester, etc. .357 magnum ammo is not the full power stuff.

  4. With that being said, the .357 is nothing but the hottest 9 MM. (What ever happened to the .357 Maximum, anyway?) After the collapse, there won’t be anyone complaining about the lack of availability of the .30RS or firearms to shoot it from. The 30-30 was great, like the .303 or the 30/06 in their time. Time has moved on and full power .45 and full power .30 caliber don’t stand or fall by popular opinion. They stand because they are the best. -30-

    • ‘the .357 is nothing but the hottest 9 MM’

      Huh?!? Both rounds have identical max pressure but the .357 has twice the case capacity – more than twice once you subtract the seated bullet. A 6″ .357 can top 800ft/lbs of energy without resorting to +p loads. The standard load for a 9mm is just 365ft/lbs from a 4″ barrel. Even +p+ 9mm loaded with lightweight bullets can’t come close to .357 power.

  5. Forgoing snark, I’ll ask if the AK74 was ever chsmbered in 7.62×39.
    My understanding was that from inception, it has been chambered in 5.45.

  6. Sorry, Gov, didn’t mean to take an adversarial position. Anyone, or anything well shot with either a 9MM or a .357 Magnum will pretty much stay shot. That is the main purpose of shooting. Shoot it, cook it, can it and then sit on the can.-30-

  7. Why are the words “self defense” obviously omitted from various sentences? Weird posting hiccup or meta-narrative on the state of the world?

  8. Every shot taken off the target range is either “defence”, protect from an attack or “defence”, prevent from starving to death. Your results may vary. -30-

  9. “The FBI famously poo-pooed the 9mm due to failure to stop bad guys (such as in the 1986 Miami shootout) ”

    When, in fact, their real problem was their inability to hit a damn thing since they brought handguns to a longgun fight.

    • No. The 115 gr Silvertips got hits, and one would have hit the heart had they penetrated deeper. It’s one of several mistakes, like unsecured weapons and glasses while colliding in vehicles.

      • But is it reasonable to give such importance to the trajectory of that one bullet?

        Most of the shots fired at Platt were misses. Of the twleve hits, ten were not ‘vital area’ hits. Two were, including the ‘inch from the heart’ shot and the final shot to the chest that stopped him for good. So if we’re going to play ‘what if’ the shot had a little more power and could go that extra inch, why not play ‘what if’ and figure out how to make a couple more of those misses hit instead? Ultimately, a more powerful cartridge doesn’t do that, but the FBI embarked on a mission that ended with an anemic 10mm when they would have been better served by a philosophy that has now become fairly well-accepted in gunfights: a handgun is useful to fight your way to a long gun.

        Playing around with questions of which handgun round is marginally better than another seems kind of silly when the real answer should have been to use something better all along. There’s a hundred different factors that went into that fight being FUBARed but for some reason a great deal of importance was placed on that one bullet instead of the other myriad reasons that things went wrong. I’d say it’s a bit of Texas sharpshooter fallacy.

    • The other part of that 1986 shootout was that the FBI got their butts handed to them, in part, because of a bad guy with a Mini-14. You know, using that “tabby among the tigers” according to the author, a .223 Rem.

      • Kurz = Short, in German. Also labeled “9mm Corto” in some European circles. And that’s not nearly the end of its monikers. It’s an ancient cartridge with factories loading it across the globe, so it goes by a slew of names.

  10. I’ve posted this link before, but Paul Harrell has a great analysis of the 1986 FBI Miami-Dade Shootout:

    • Harrell has also shown that FMJ is as or more destructive than high dollar “hyper ammo.”

      So a 40SW or 45ACP FMJ is still a better choice than any fancy 9MM ammo.

      Because 9MM sucks.

      • Does anyone make a 15 round 40 s&w hand gun?
        Does anyone make a 15 round 45acp hand gun?
        If they do there must be a very good reasons why no one’s buying them. I don’t see them featured in any literature. And the police and military are not using them.

        Ammunition capacity is King in the 21st century.

        • I saw a cop shoot a paralyzed deer in the head, four feet away, four times before it died The deer just stared, and looked around at the cop every time he shot at it like the bullets were just bouncing off of its skull. 9mm is under powered junk. You need 3 bullets to do the same thing as one 45 ACP bullet, so of course the 9mm pistols have huge capacities. As long as you don’t miss, you don’t need any more than 7 bullets in a magazine.

      • Haha, figures the glock-guy is one that says FMJ (40 or 45) is equal to or better than HP (9mm). My goodness these guys never tired of making @sses out of themselves.

      • “Harrell has also shown that FMJ is as or more destructive than high dollar “hyper ammo.””

        It’s easy to get results you want from a test whose parameters you create with those results in mind. I have no idea what you mean by ‘destructive’ (how many water jugs it shoots?) but the idea that FMJ is more useful as a defensive round in general is downright asinine and countered by decades of ballistic research.

  11. Now we come to 9mm… [whose] recoil is light enough for almost any shooter to tolerate it, even in subcompact rounds.

    I never knew about subcompact 9 mm rounds. It seems I’ve been loading my subcompact pistol with the wrong stuff all this time.

  12. My favorite tight patterning, factory loaded 12 gauge buckshot round fires three 22 gauge* hard cast lead pellets!

    * .60″ 315 grain buckshot pellets: Tri-Ball 3″ from Dixie Slugs Co.

  13. I reload .308Win. The new plastic tips are amazingly accurate, even out of a POS barrel (I shoot a Ruger American .308.)

    I initially avoided buying more rifle than my trigger finger deserved. Recently fired three rounds to warm up the barrel, and all three holes (100yds) could be covered by a quarter. I may deserve a better rifle.

    .308Win is very forgiving, and pretty much will put anything in North America in the freezer. (Please keep your Alferd Packer jokes to yourself.)

  14. I didn’t see a difference at 300 yards, past that it is not as good. , the trade off in recoil and cost, that’s why I used the other more then that one

    • And a myth that needs to die.
      According to the DOJ’s Bureau of Crime statistics (you can look up multiple years online) the 22, even when both 22 pistol and rifle use are combined, falls behind numerous other pistol rounds in number of homicides. In fact, if we take a look at the number of 22 stolen, or the number used in crimes, and compare that to percentages of homicides, we see the ratio is dramatically skewed toward lots of people shot, not many of them dying.

      • I suspect this MAY have been true at some point but the medical field has gotten much better at treating gunshot wounds over the past couple of decades.

        • (specifically: better at treating small caliber wounds and tracks that tend to cause diffuse bleeding and infection)

  15. The Whinchester .350 Legend (unveiled at the last SHOT Show as “the world’s fastest straight-walled cartridge!”) is already being hyped as if it’s even better than the 6.5 Creedmoor. If you believe Winchester’s hype about the .350 Legend, it’s the best deer-killing round on the planet, has zero recoil, infinite penetration, and will fit every type of rifle from the AR-15 (true, CMMG is already making AR-15 uppers for it) and bolt-actions (true, Winchester Repeating Arms is making them) to lever-actions (doubtful, as .350 Legend is a rimless cartridge).

    I confess that I like the idea of the .350 Legend (it sounds a lot like the .357 AR wildcat, which is based on the .357 MAXIMUM), but I don’t know how much of the hype to believe. Is it really more powerful than 30-30 with less recoil, greater range, and more penetration?
    Or is it simply duplicating the power of a 300 Blackout in a straight-walled cartridge?

  16. So when talking about .380 ACP, did you mean 9mm Browning? The text says 7mm Browning but that is obviously a typo.

    • Not out of my boutique squeezebore French auto from 1926. Sure, it’s a 9mm at the chamber, but it’s a 7mm bore.

  17. When you’re older and arthritis makes the heavier calibers painful to shoot, .380 provides a good self defense option.


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