Caliber equivalency (sort of)

I have been in a couple conversations lately where some people have shot or found magazines filled with a different caliber than their gun was designed for.

One friend has a 7mm Ruger (Luger?) and the local gunsmith told him he could shoot 32acp through it. Another acquaintence yesterday got his Dad's 9mm Luger down from the shelf and found the magazine crammed with .38 cartridges.

So with all the different calibers out there which ones can be shot or will fit another?

I know the following:

.38, 38 special, .38 super but they are the same caliber for a 38 pistol
.44 special, 44 magnum (same for a 44 pistol)
Also some guns change barrels for .357 and .40 s&w.

So assuming at least a single shot (maybe feed jams) can a 9mm shoot 38?
Or what about a 9mm shooting a .380?
I also think a 10mm can fire a 40s&w but don't know about reliably.
Are there any other caliber crossbreeds I should know about?

This is simply curiousity and I don't intend to try a particular combination.

7.63 Mauser and 7.62 x 25 mm Tokarev can fire, but one of the two will blow up the other, so it only works one way. (I think you can shoot 7.63 Mauser out of Tokarev guns, but the Tokarev rounds is too hot for Mausers)

7.62 Nagant revolvers can have .32 fired out of them if my memory serves me correctly, but they won't achieve the seal.

.40 S&W can shoot 357sig or 9mm (use conversion barrels)
10mm xan shoot .40, 357sig, or 9 x 25 Dillon /w conversion barrels
45 ACP can shoot 10mm with conversion barrel but needs extractor mods because the breech face is too large

There are also head space issues that can't be resolved without a barrel conversion.

I don't think you can reliably shoot 10mm from a 45 ACP even with a different barrel because the breech face is too large and the extractor will be loose. Some folks have done it with no issues. Some not. I wouldn't do this for a carry piece. Range would be ok.

I have a KKM 40 conversion barrel for my G29 (10mm) and it works flawlessly. Saves a ton of money on ammo. The 40 can use the 10mm mags. They are essentially the same caliber.

So ignoring conversion barrels can 38, 380 be shot in a 9mm barrel?

What about if I took a 45 Long Colt and manually loaded it in a 45acp pistol. I assume it would fire but just not extract.

I am mainly curious about the 38, 380, 9mm though.

I don't know that much about interchangeability, but .38 and .38sp will NOT shoot out of the same gun. I don't believe .38 super is interchangeable with either of those either.

.38 special will shoot out of a .357 magnum.

45acpForMe said:

So ignoring conversion barrels can 38, 380 be shot in a 9mm barrel?

What about if I took a 45 Long Colt and manually loaded it in a 45acp pistol. I assume it would fire but just not extract.

I am mainly curious about the 38, 380, 9mm though.

Click to expand...

NO, it won't even come CLOSE to fitting!
As for .38's in general: you can shoot .38 Spl out of a .357 Mag.
You can shoot a .45 Long out of a .44 Magnum.
Now stop. There ARE others BUT there are caveats to almost all of them. Shoot what the gun was designed to fire ONLY to be safe.

To see SOME of the differences in cartridges, poke around here:
http://herohog.com/images/guns/ammo/

A REAL good example of a way to get hurt shooting other ammo that looks the same and measures the same length and diameter but CAN KILL YOU is best exemplified in the Spanish made Star Modelo(model) Super pistol.

It is made to fire the 9x23mm Spanish Largo round. You CAN chamber and fire a 9x23 Winchester in it BUT that cartridge is WAY more powerful and CAN cause the gun to blow up in your face!

Same for the .38 Super. It too will fit and fire in the Star Super (most models) but it too is WAY over spec on that gun!

Many claim that you can shoot .380 ACP and 9mm Luger in a Star Super and while they aren't over powered and of approximately proper diameter, they only work because of the extractor holding the bullet against the breech face as they are designed to seat on the case mouth, NOT the rim! What this does is leave a large gap between the lands and grooves of the barrel and the bullet that it has to jump on firing and that can lead to issues especially when you go back and try to shoot the ammo it is designed for.

Let's ADD to the confusion, shall we? Some Supers are marked 9mm Largo/.38 on the barrels. That is because that gun CAN also fire the .38 Auto cartridge which is NOT either a .38 Super or .38 Special but an older .38 caliber semi-rimmed cartridge with lower power.

All that for ONE pistol/cartridge combination! THAT is why we always stress that you should what a gun is chambered PERIOD.

HeroHog said:

To see SOME of the differences in cartridges, poke around here: http://herohog.com/images/guns/ammo/

Click to expand...

What a beautiful picture. I would have lined them up a little differently but still nice.

This was an exercise in curiousity and I have no intention of blowing up my face (or guns) trying something stupid. Just people keep saying that a .380 is the same as a 9mm just shorter and the like so I was wondering if the were really the same or had other differences. From the picture there are a number of other calibers I didn't even know existed so that adds a bunch of "would it work" questions which I guess are left unanswered. :-(

Most of those images were not made by me so I can't take the credit/blame for most of the layout. I just tried to assemble the widest examples of cartridges I could so that folks could see what has been made and compare one to another.

On the 9mm VS. .380, the .380 is less powerful, shoots a lighter projectile and I believe that besides length, their specifications are CLOSE but not exactly the same (I think. Don't have my ref. handy).

You have to really watch out for "X will work just fine in Y" examples as there is usually a grain of truth in there but some BIG "got-ya's" in there that can get ya hurt/hurt yer gun. Ya did the right thing coming here and asking around.

45acpForMe said:

I have been in a couple conversations lately where some people have shot or found magazines filled with a different caliber than their gun was designed for.

One friend has a 7mm Ruger (Luger?) and the local gunsmith told him he could shoot 32acp through it. Another acquaintence yesterday got his Dad's 9mm Luger down from the shelf and found the magazine crammed with .38 cartridges.

So with all the different calibers out there which ones can be shot or will fit another?

I know the following:

.38, 38 special, .38 super but they are the same caliber for a 38 pistol
.44 special, 44 magnum (same for a 44 pistol)
Also some guns change barrels for .357 and .40 s&w.

So assuming at least a single shot (maybe feed jams) can a 9mm shoot 38?
Or what about a 9mm shooting a .380?
I also think a 10mm can fire a 40s&w but don't know about reliably.
Are there any other caliber crossbreeds I should know about?

This is simply curiousity and I don't intend to try a particular combination.

Click to expand...

.38 special is a revolver round--although some lever action rifles are chambered for it. .38 Super is strictly a pistol round for 1911s. They are NOT interchangable. 10mm will safely shoot .40 S&W--not the other way around. .380 are 9x17mm; 9mm Luger are 9x19 NOT interchangable, neither is the 9X18 Makarov round.

7mm is a rifle round. No resemblance to a .32 ACP for pistols or .32 H&R for revolvers.

Gunslinger said:

.38 special is a revolver round--although some lever action rifles are chambered for it. .38 Super is strictly a pistol round for 1911s. They are NOT interchangable. 10mm will safely shoot .40 S&W--not the other way around. .380 are 9x17mm; 9mm Luger are 9x19 NOT interchangable, neither is the 9X18 Makarov round.

7mm is a rifle round. No resemblance to a .32 ACP for pistols or .32 H&R for revolvers.

Click to expand...

So , in the same sentence you say that it is both safe and unsafe to do essentially the same thing?

The 10mm Automatic WILL NOT safely shoot .40 S&W!

10mm Auto = 10x25mm and .40 S&W = 10x22mm just like .380 Auto = 9x17mm and 9mm Luger = 9x19mm

All of these cartridges headspace on the casemouth, not on the extractor grove. Shooting the short cartridge in the long chamber will cause headspacing issues like stretched cases, severely flattened/pierced/blown primers, degraded accuracy, accelerated wear and tear on the gun AND you risk having a kB!

So, you might get away with shooting 40s&w in your 10mm just like you might get away with shooting .380 in your 9mm but is it worth losing your fingers and damaging your face/eyes?

If you want to shoot 40 out of a 10mm, buy a conversion barrel.

Barnett3006 said:

So , in the same sentence you say that it is both safe and unsafe to do essentially the same thing?

The 10mm Automatic WILL NOT safely shoot .40 S&W!

10mm Auto = 10x25mm and .40 S&W = 10x22mm just like .380 Auto = 9x17mm and 9mm Luger = 9x19mm

All of these cartridges headspace on the casemouth, not on the extractor grove. Shooting the short cartridge in the long chamber will cause headspacing issues like stretched cases, severely flattened/pierced/blown primers, degraded accuracy, accelerated wear and tear on the gun AND you risk having a kB!

So, you might get away with shooting 40s&w in your 10mm just like you might get away with shooting .380 in your 9mm but is it worth losing your fingers and damaging your face/eyes?

Click to expand...

Yoy're correct about headspacing on the case mouth. I hadn't considered that. 10mm revolvers will fire .40 S&W much as .357s fire .38 spcls with no problems. While I don't really see any problem other than a primer blowing, I agree that shooting them in a semi-auto is a bad idea.

Another one to know of is 9x18 makarov. It looks a lot like 9x19 but is not interchangeable. 9mm mak is actually larger in diameter than the 9x19, I believe it is .364" and not .355" (I don't know these numbers off the top of my head for sure, but you get the idea) and 9mm mak is lower pressure.

If you want to check compatibility look in a reloading book. The bullet diameters should be exactly the same. The cases should be compatible; for revolvers a shorter case can go in a longer gun, but not the other way around. Autoloaders require the same size case for safe operation. Also check the pressure of the loads, if the max pressure of the new cartridge is higher than the cartridge the gun is designed for then it is not safe for that gun. Of course it is easier to just use only what the gun is marked for and avoid any dangerous consequences of doing otherwise.

Gunslinger said:

Yoy're correct about headspacing on the case mouth. I hadn't considered that. 10mm revolvers will fire .40 S&W much as .357s fire .38 spcls with no problems. While I don't really see any problem other than a primer blowing, I agree that shooting them in a semi-auto is a bad idea.

Click to expand...

Well go ahead and add some more confusion to the mix with your 10mm Auto chambered revolver

While having the occasional pierced/blown primer may not be that much of a problem, it does allow the high pressure gas to travel through the firing pin hole. Doing something that will cause pierced and blown primers with some amount of regularity (such as shooting .40s&w in a 10mm auto pistol) can cause breechface and firing pin hole erosion do to gas cutting. This will make your pistol unsafe to shoot with any ammo including that which it was designed to shoot.

A pretty good read on the subject http://www.thegunzone.com/10v40.html

sonoran_Tj said:

Another one to know of is 9x18 makarov. It looks a lot like 9x19 but is not interchangeable. 9mm mak is actually larger in diameter than the 9x19, I believe it is .364" and not .355" (I don't know these numbers off the top of my head for sure, but you get the idea) and 9mm mak is lower pressure.

If you want to check compatibility look in a reloading book. The bullet diameters should be exactly the same. The cases should be compatible; for revolvers a shorter case can go in a longer gun, but not the other way around. Autoloaders require the same size case for safe operation. Also check the pressure of the loads, if the max pressure of the new cartridge is higher than the cartridge the gun is designed for then it is not safe for that gun. Of course it is easier to just use only what the gun is marked for and avoid any dangerous consequences of doing otherwise.

Click to expand...

Your correct about the bullet diameters. But, one to really watch for is 9x18mm Ultra Police cartridge. The 9x18 Ultra cartridge operates at same pressures and produces the same velocities with the same bullet Weight as the 9x18mm Makarov (and even looks the same) but uses a .355 diameter bullet like the .380acp or 9mm Luger.

I see 9x18mm Ultra pistols and ammo pop up from time to time at gunshows or on the back shelf guns shops that have been in the biz for along time.

Then there's the "9mm" Largo, just to add further confusion...9x23mm I think. Mainly Spanish made pistols.

If you're looking for a gun that is multi-caliber get a revolver.

Ruger makes several SA revolvers that with nothing more than a cylinder switch it can fire:
38/40 and 40SW/10mm
38/357 mag and 9mm
45LC/45AR and 45 auto
Also revolvers chambered in .460SW can fire, 454 casull, 45LC, 45 AR(autorim) and 45 schofield.

Interesting stuff, herohog. Thanks for posting.

45acpForMe said:

I have been in a couple conversations lately where some people have shot or found magazines filled with a different caliber than their gun was designed for.

One friend has a 7mm Ruger (Luger?) and the local gunsmith told him he could shoot 32acp through it. Another acquaintence yesterday got his Dad's 9mm Luger down from the shelf and found the magazine crammed with .38 cartridges.

So with all the different calibers out there which ones can be shot or will fit another?

I know the following:

.38, 38 special, .38 super but they are the same caliber for a 38 pistol .44 special, 44 magnum (same for a 44 pistol)
Also some guns change barrels for .357 and .40 s&w.

So assuming at least a single shot (maybe feed jams) can a 9mm shoot 38? Or what about a 9mm shooting a .380?
I also think a 10mm can fire a 40s&w but don't know about reliably.Are there any other caliber crossbreeds I should know about?

This is simply curiousity and I don't intend to try a particular combination.

Click to expand...

.38 Super and .380 are the same as 9MM. .355 .38 Special and .357 magnums are .357

NO
.380 in 9MM would have reliabilty problems as well as .40 in 10MM

BTW, a Taurus Judge will shoot .45 Long Colt and .410 shotshells.