Handgun Calibers Chart (2026): 15 Pistol and Revolver Calibers by Bullet Size, Speed and Pressure

Last updated October 26th 2026

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By Nick Hall, who wrote our .32 ACP ammo guide and best concealed carry ammo rankings.

Handgun calibers run from the tiny .25 Auto, with a .251 inch bullet, to the .500 S&W Magnum, with a half-inch bullet and 60,000 psi of chamber pressure. The chart below covers the 15 pistol and revolver cartridges you’re most likely to see on a box of ammo, with the bullet diameter, case length, overall length, velocity and maximum pressure for each.

Every figure comes from one place: ANSI/SAAMI Z299.3-2022, the industry standard for centerfire pistol and revolver ammunition. SAAMI is the body that sets the dimensions and pressure limits American ammo makers load to. The other caliber charts in the search results don’t cite it, and that’s how some of their numbers drift. A few of these figures surprised me, starting with the fact that a .38 Special bullet isn’t .38 inches.

Table of Contents

Handgun Calibers Chart

Caliber	Bullet diameter (in.)	Case length (in.)	Overall length (in.)	Sample bullet	SAAMI velocity	Energy	Max pressure
.25 Auto	.2510	.615	.860 to .910	50 gr	755 fps	63 ft-lb	25,000 psi
.32 Auto (.32 ACP)	.3125	.680	.890 to .984	71 gr	900 fps	128 ft-lb	20,500 psi
.380 Auto (.380 ACP)	.3565	.680	.910 to .984	95 gr	945 fps	188 ft-lb	21,500 psi
9mm Luger	.3555	.754	1.000 to 1.169	115 gr	1,135 fps	329 ft-lb	35,000 psi
.357 SIG	.3555	.865	1.100 to 1.140	125 gr	1,350 fps	506 ft-lb	40,000 psi
.40 S&W	.4005	.850	1.085 to 1.135	180 gr	985 fps	388 ft-lb	35,000 psi
10mm Auto	.4005	.992	1.240 to 1.260	180 gr	1,030 fps	424 ft-lb	37,500 psi
.45 Auto (.45 ACP)	.4530 lead / .4520 jacketed	.898	1.190 to 1.275	230 gr	830 fps	352 ft-lb	21,000 psi
.38 Special	.3590 lead / .3580 jacketed	1.155	1.275 to 1.550	158 gr	900 fps	284 ft-lb	17,000 psi
.357 Magnum	.3590 lead / .3580 jacketed	1.290	1.405 to 1.590	158 gr	1,545 fps	837 ft-lb	35,000 psi
.327 Federal Magnum	.3130	1.200	1.275 to 1.475	100 gr	1,600 fps	568 ft-lb	45,000 psi
.44 S&W Special	.4325	1.160	1.415 to 1.615	240 gr	800 fps	341 ft-lb	15,500 psi
.44 Remington Magnum	.4320 lead	1.285	1.535 to 1.610	240 gr	1,175 fps	736 ft-lb	36,000 psi
.45 Colt	.4560	1.285	1.515 to 1.600	250 gr	750 fps	312 ft-lb	14,000 psi
.500 S&W Magnum	.500	1.625	1.900 to 2.250	400 gr	1,800 fps	2,877 ft-lb	60,000 psi

Bullet diameter, case length and overall length are SAAMI’s maximum cartridge dimensions, read from its drawings. Velocity is SAAMI’s nominal figure for the sample bullet weight, measured 15 feet from the muzzle of a standard test barrel, and where SAAMI lists several velocities for one weight, I used the first. Energy is calculated from that weight and velocity. Pressure is SAAMI’s maximum average pressure for standard loads, measured with a piezo transducer.

The Name on the Box Is Not the Bullet Size

Handgun cartridge names are marketing and history, not measurements. Three examples straight from SAAMI’s drawings:

• .38 Special is a .357 bullet. SAAMI draws it at .3590 inch for lead and .3580 for jacketed, exactly the same as the .357 Magnum. The “.38” came from the old heeled bullets of the 1800s, when the bullet’s outside diameter matched the case.
• .380 Auto fires a slightly wider bullet than 9mm Luger. SAAMI’s maximum is .3565 inch for the .380 and .3555 for the 9mm. They aren’t interchangeable, because the .380 case is .680 inch long and the 9mm case .754.
• .44 Magnum is a .43. SAAMI draws the lead bullet at .4320 inch, and the .44 Special at .4325.

This is why handloaders buy bullets by diameter, not by caliber name, and why “.357” bullets work in both .38 Special and .357 Magnum. For rifle cartridges, see our rifle caliber guide.

How to Read the Caliber on a Box or Headstamp

SAAMI publishes an official full name and abbreviated name for every cartridge, and it says those names “should be used on cartridge headstamps and on firearm markings to properly identify the caliber.” That’s why the same round shows up under different labels:

What you might see	SAAMI full name	SAAMI abbreviation
9mm, 9×19, 9mm Parabellum	9mm Luger	9mm Luger
.380 ACP, 9mm Kurz, 9mm Short	380 Automatic	380 Auto
.32 ACP, 7.65 Browning	32 Automatic	32 Auto
.45 ACP	45 Automatic	45 Auto
.40 Cal, .40 S&W	40 Smith & Wesson	40 S&W
.44 Mag	44 Remington Magnum	44 Rem Mag
.38 Spl	38 Special	38 Spl

The rule that keeps you safe is simple: the name stamped on the barrel or slide has to match the headstamp on the case. “9mm” alone isn’t enough, because 9×18 Makarov and 9×23 Winchester are separate SAAMI cartridges with their own chambers, and .380 Auto is a 9mm too. When in doubt, read the full name.

Bullet Weight: What the Grain Number Means

The grain figure on a box is bullet weight, not powder, and there are 7,000 grains in a pound. Every caliber is loaded in a range of weights, and SAAMI lists a separate velocity for many of them. The 9mm Luger table alone runs from 88 grains at 1,500 fps to 150 grains at 900 fps. Lighter bullets go faster and kick with a sharper snap. Heavier bullets go slower, hit with more momentum and feel more like a push. The sample weights in the chart above, like 115 grain 9mm and 230 grain .45, are the common practice loads, which is why they’re also the cheapest boxes on the shelf.

Same Bullet, Different Cartridge

Several handgun calibers share a bullet and differ only in the case behind it. SAAMI’s drawings make the families easy to see:

Bullet diameter	Cartridges that use it	What changes
.3555 in.	9mm Luger, .357 SIG	The .357 SIG is a bottlenecked case, .865 inch long, loaded to 40,000 psi against the 9mm’s 35,000
.4005 in.	.40 S&W, 10mm Auto	The 10mm case is .992 inch long against the .40’s .850, and SAAMI allows it 37,500 psi
.3580 to .3590 in.	.38 Special, .357 Magnum	Same rim and body, but the Magnum case is 1.290 inch against 1.155, and 35,000 psi against 17,000
.4320 to .4325 in.	.44 Special, .44 Magnum	The Magnum case is 1.285 inch against 1.160, and 36,000 psi against 15,500

The revolver pairs matter most. The Magnum cases were made longer on purpose, so a Magnum round won’t drop into the shorter chamber of a .38 Special or .44 Special revolver built for far lower pressure. Going the other way, a .357 Magnum revolver is commonly listed by its maker as able to fire .38 Special, and a .44 Magnum revolver .44 Special, which is why so many people practice with the softer round. Check your gun’s manual before you try it.

Which Handgun Calibers Run the Hottest?

Pressure is what the gun has to contain, and it ranges more than fourfold across handgun calibers. The .45 Colt and .44 Special, both from the black-powder and early smokeless era, sit at 14,000 and 15,500 psi. Modern autoloader cartridges like 9mm and .40 S&W sit at 35,000. The .500 S&W Magnum is loaded to 60,000, as high as many rifle cartridges.

+P is a separate, higher limit, and only some calibers have one. SAAMI lists +P pressures for four handgun cartridges:

Cartridge	Standard max	+P max
9mm Luger	35,000 psi	38,500 psi
.38 Special	17,000 psi	20,000 psi
.45 Auto	21,000 psi	23,000 psi
.38 Super Auto	Not listed	36,500 psi (sold only as +P)

SAAMI’s own footnote says +P ammunition should be used “only in firearms especially designed for this cartridge and so recommended by the manufacturer.” There’s no SAAMI +P for .380, .40 S&W, 10mm or .32 Auto, so a +P label on those boxes is the ammo maker’s own claim. Our .32 ACP ammo guide covers what that means in practice.

Why Your Revolver Is Slower Than the Box

SAAMI measures revolver ammunition two ways: in a solid test barrel, and in a vented barrel that leaks gas at the gap like a real revolver’s cylinder. The vented numbers are lower, sometimes by a lot:

Load	Solid test barrel	Vented test barrel	Difference
.38 Special, 158 gr	900 fps	750 fps	150 fps
.357 Magnum, 158 gr	1,545 fps	1,220 fps	325 fps
.44 Magnum, 240 gr	1,500 fps	1,150 fps	350 fps

SAAMI notes that vented barrels “are used for the establishment of catalog velocity values for cartridges normally chambered in revolvers,” and it also warns that you shouldn’t expect to duplicate its velocities from a real gun. Short barrels lose more again. When a box of .357 says 1,450 fps and your snub-nose chronographs 1,150, nothing is wrong with the ammo.

Pocket and Backup Calibers: .25, .32 and .380

These three are blowback-pistol cartridges built for small guns. The .25 Auto throws a 50 grain bullet at 755 fps for about 63 foot-pounds, which is why few people carry one now. The .32 Auto roughly doubles that, and the .380 Auto at 95 grains and 945 fps gets about 188 foot-pounds, close to three times the .25. All three are loaded to modest pressures, 20,500 to 25,000 psi, which is what lets them work in light, simple pistols. If you’re choosing a gun, see our best .380 pistols and best .32 ACP pistols.

Service Pistol Calibers: 9mm, .40 S&W, .45 ACP, 10mm and .357 SIG

These are the duty and carry calibers most people mean when they say “handgun.” The 9mm Luger is the default: a .3555 inch bullet at 35,000 psi, cheap to shoot and the easiest pistol round to find. The .45 Auto fires a much heavier, wider bullet at far lower pressure, 21,000 psi, and SAAMI’s 230 grain figure starts at 830 fps. The .40 S&W shares its bullet with the 10mm and sits between 9mm and 10mm in energy. For the head-to-heads, read 9mm vs .45 ACP, 9mm vs .45 vs .40 and 9mm vs 10mm.

Revolver Calibers: .38 Special to .500 S&W

Revolver cartridges are rimmed and straight-walled, and they span the widest range on the chart. The .38 Special is the soft-shooting classic at 17,000 psi. The .357 Magnum doubles that pressure and, from SAAMI’s solid test barrel, pushes a 158 grain bullet at 1,545 fps for about 837 foot-pounds. The .327 Federal Magnum runs the highest pressure of the mid-size revolver rounds, 45,000 psi. The .44 Magnum and .500 S&W are hunting and bear-country cartridges, and the .45 Colt and .44 Special are the low-pressure classics for older and cowboy-style guns.

Which Handgun Caliber Should You Buy?

• First gun, carry or home defense: 9mm Luger. It’s the cheapest to practice with, it’s in every gun store, and modern defensive loads perform well. See our concealed carry ammo and home defense ammo rankings.
• Smallest pocket gun: .380 Auto, or .32 Auto if recoil or racking the slide is a problem.
• Revolver for the house or the truck: .357 Magnum, which also shoots .38 Special for practice in most revolvers.
• Woods and bear country: 10mm Auto in a pistol, .44 Magnum or bigger in a revolver.
• Already own a .45 or .40: keep shooting it. The ballistics haven’t gotten worse, though the ammo costs more than 9mm.

What About .22 LR?

The .22 Long Rifle is a rimfire cartridge, so it lives in a different SAAMI standard, Z299.1, with its own test barrels, and isn’t on this chart. It’s the cheapest round to learn on, but it’s a training and small-game cartridge first. All SAAMI standards are free from the SAAMI standards page.

Frequently Asked Questions