# Handgun ammunition



## fivehourfrenzy (Aug 12, 2007)

I'm curious to differences in handgun bullets, and what makes them what they are. We'll only pertain to SD rounds.

.380ACP
Makarov
9mm para
.38 special
.38 super
.357 mag

^^All these have 9mm diameters, but how do they differ? I know 9mm para is 19mm long, .380ACP is 9x17, Makarov is 9x18. So if you're gun is chambered for 9mm para, why could you use the shorter 9mm rounds?

What makes a magnum a magnum?

How does 9mm para differ from .38 special in ballistics?

Why is there a 3-digit caliber designation on a handgun round, such as .380ACP and .357?

Calculated out, 9mm is .354 inches, which is different than .380 inches. I would guess the caliber designation is used to decipher between different cartridges.

What is a .357 sig, and how does it compare to a .357 mag?

.40S&W
10mm

^^Same diameters, but .40S&W is smaller. Could you use .40S&W in a 10mm? And isn't a .357 sig a shorter version of a .40S&W, so could you use a .357 sig in a .40S&W-chambered gun?

.45ACP
.45 short colt
.45 long colt

^^So can .45ACP be referred to as "45 colt." The same goes with .380ACP, .32ACP, .25ACP...are they "380 colt, 32 colt, 25 colt?"


----------



## hawcer (Feb 22, 2008)

This is how i see it...as for revolver rounds go, their cases are rimmed.so any length shell or bullet can be used as long as it is the correct caliber and the total length will fit into the cylinder.
Edit: For example-- A .22 revolver can be loaded with .22 short,.22 long or .22lr.
And a .357 magnum can also be loaded with the shorter 38 rounds

The un-rimmed auto casings require a certain headspace.

Example: Putting a 9x18 into a 9x19 chamber will allow the round excessive movement between the breech face and the chamber.you may not even get a primer strike.Or it could be very dangerous if you do.(not completely containing the pressure)

The 357 sig is a necked down 40 s&w ...kinda like the 400 corbon is a necked down 45acp.

But...I am just a novice at this stuff.I'm sure a pro will answer with much better,more accurate information.


----------



## fivehourfrenzy (Aug 12, 2007)

What is rimmed?


----------



## hawcer (Feb 22, 2008)

fivehourfrenzy said:


> What is rimmed?


has a raised "lip" or rim around the bottom of the shell...look at a 22lr round.now you know why it is called a rimfire. 

Now hear is a question I will ask,since we are on the subject.

Would it be possible to ream out a .380 chamber to a 9x18 or 9x18 to a 9x19 and have it work correctly?I foresee possible feeing problems,But what about chamber pressures?

Somewhat of an answer I found for the both of us....

The 380acp,like the Makarov(9x18), it is most often fired from _blow back _semiautomatics ,not the _locked breech _common to higher-pressure rounds like the 9x19mm.


----------



## Mike Barham (Mar 30, 2006)

fivehourfrenzy said:


> .380ACP
> Makarov
> 9mm para
> .38 special
> ...


They differ in case length and design.

.380, Mak and 9mmP are rimless designs. They actually do have a rim, for the extractor to grab, but it is flush with the case body. These rounds all headspace on the case mouth.

.38 Super has a "semi-rim," meaning a small/narrow rim. This round used to headspace on the semi-rim in the old Colt 1911s, which led to mediocre accuracy. More recent Supers headspace on the case mouth for better accuracy.

.38 Special and .357 Mag have a rim, which allows the extractor star on a revolver to punch them out of the cylinder. These rounds headspace on the rim.



> What makes a magnum a magnum?


Same thing that makes a big wine bottle a magnum: extra capacity.



> How does 9mm para differ from .38 special in ballistics?


They are similar in some respects, but the 9mmP usually has somewhat more velocity and energy for similar bullet weights.



> Why is there a 3-digit caliber designation on a handgun round, such as .380ACP and .357?


Mainly tradition and to make it easy to differentiate between similar cartridges.



> Calculated out, 9mm is .354 inches, which is different than .380 inches. I would guess the caliber designation is used to decipher between different cartridges.


Welcome to the wonderful world of caliber marketing. .44s are .429s. .38s are .357s. It's part catchy name, and part differentiating a cartridge from the pack. How cool would Dirty Harry have been if he threatened street thugs with "_a .429 Magnum, the most powerful handgun in the world_?"



> What is a .357 sig, and how does it compare to a .357 mag?


The SIG case is a rimless bottleneck (looks like little tiny rifle round), while the Magnum is a rimmed straight-walled revolver round.

Ballistically, the SIG gives up little to the Magnum, maybe a 50-100fps.



> .40S&W
> 10mm
> 
> ^^Same diameters, but .40S&W is smaller. Could you use .40S&W in a 10mm?


.40 is designed for guns with 9mm cycle length. 10mm fits in gun with .45ACP cycle length. People have fired .40 in 10mm pistols, but the case is forced to headspace on the extractor rather than the mouth, and both accuracy and reliability of ignition suffer. .40 may not reliably cycle a 10mm, also, because it is so much shorter and autos are sensitive to a round's overall length (OAL).



> And isn't a .357 sig a shorter version of a .40S&W, so could you use a .357 sig in a .40S&W-chambered gun?


.357 SIG is a .40 case _necked down_ to .355. You can usually fire SIGs in a .40, but you have to change the barrel first.



> .45ACP
> .45 short colt
> .45 long colt
> 
> ^^So can .45ACP be referred to as "45 colt."


No. .45 Colt is the more proper name for .45 Long Colt. .45ACP is sometimes called .45 Auto. Not sure what a .45 Short Colt is.



> The same goes with .380ACP, .32ACP, .25ACP...are they "380 colt, 32 colt, 25 colt?"


ACP stands for "Automatic Colt Pistol." However, if you attempt to buy ".25 Colt" ammo, I guarantee you will get some funny looks in the gun shop.


----------



## Mike Barham (Mar 30, 2006)

hawcer said:


> Would it be possible to ream out a .380 chamber to a 9x18 or 9x18 to a 9x19 and have it work correctly?I foresee possible feeing problems,But what about chamber pressures?


You're on the right track. A blowback 9mm on a .380 frame would kick hard and tear most .380s to pieces in short order. The higher pressure, more powerful rounds only work well in locked breech designs. There are some blowback 9mms, but the slides have to be huge and heavy, so they move slowly enough to the gun to work and not fall apart. The Hi-point pistols are blowbacks - look at the size of the slide.

Anyway, since 9mmP is 2mm longer in case length than .380, it probably won't fit in the mag well, or the ramp/barrel area.


----------



## fivehourfrenzy (Aug 12, 2007)

What's the difference in blowback and locked breech?


----------



## Mike Barham (Mar 30, 2006)

In blowback, the pressure of the recoil spring and the inertia of the slide holds the gun together at the instant of ignition. Then the slide goes straight to the rear.

In locked breech, the barrel and slide are "locked" together and recoil together for a short distance, allowing chamber pressure and slide velocity to dissipate. Then the barrel drops down and out of the way so the slide can continue its rearward travel. Your XD functions like this.


----------



## nukehayes (Sep 22, 2006)

your P22 is blowback. Note the fixed barrel when you strip it.


----------



## fivehourfrenzy (Aug 12, 2007)

Okay that makes sense. So when your talking about a gas-operated handgun, is that the same as blowback?

And why are some blowback and some locked breech?


----------



## Dredd (Feb 22, 2008)

that's a ton of questions in a short space and a ton of answers in a short space :smt023


----------



## 69Roadrunner (Nov 17, 2007)

fivehourfrenzy said:


> Okay that makes sense. So when your talking about a gas-operated handgun, is that the same as blowback?
> 
> And why are some blowback and some locked breech?


Mike has touched on some of your questions. To answer your first one - gas operated is not the same as blow back. A gas-operated action is a locked breech where the action is opened by gas bled from the barrel. The gas can either act upon a piston which pushes the action open or, direct impingement similar to the ar-15/M-16 action where the gasses act directly on the action. An example of a gas operated action in a pistol is the old Auto-Mag.

As Mike has indicated, you can have a blow back action with just about any centerfire pistol cartridge. The problem is the amount of mass and spring pressure would make for an large and unwieldy pistol - think of the UZI pistol with its heavy reciprocating bolt. A locked breech eliminates the need for a heavy slide/heavy spring and usually makes for a more compact pistol - compare the relative size and weight of the Walther PPK (blowback) with the Kel-Tec P-3AT (locked breech).


----------



## vel525 (Feb 13, 2008)

fivehourfrenzy said:


> What makes a magnum a magnum?


Same reason I use a magnum condom...IT'S BIG :smt082
Sorry, couldn't resist. :smt033


----------



## jimg11 (May 17, 2006)

*Question?*

Mike you did a great job on the answers

I might point out that the 9 X 18 Makarov has a larger diameter bullet than the rest of the (.363") european /American 9mms because the Russians did it that way. The rest of the 9mms are .354-.356"

the 38 S&W / 38 Colt New Police has a larger diamemeter bullet >360" and case .385 versis the 38 Special and 357 Mag. .357 bullet and .376 case.


----------



## JeffWard (Aug 24, 2007)

If a .380 auto is a "shorter" 9mm, then why is the case diameter and rim smaller??? Or is it the just the rim (when looked at from behind)?

I assume if both shoot a .357 diameter bullet, it must just be the .380 "ACP" rim, vs the 9mm "Parabellum" rim? You cannot trim down a 9mm case to fire in a .380, or bore out a .380 to shoot 9mm ammo. The rim size IS smaller.

The Makov just looks shorter... than the 9mmX19.

JW


----------



## Mike Barham (Mar 30, 2006)

Have you miked the .380 rim versus the 9mm, *Jeff*? I'm sure a reloading manual would have the specs. I suppose it's a minor technical difference, but you can't just make a .380 into a 9mm anyway even if you could "bore it out." The gun would never survive, even if you could get the 9mm and fit and feed.


----------

