Why is a .380 a .380?

Nate1778 · May 29, 2009, 12:47 PM

Don't know if this is the right forum for this but can someone explain how this came about. I have Wiki'ed the subject with no answer. If the bullet is .355-.356 where did the .380 come from? Just bugged me since my last order of bullets arrived.

rantingredneck · May 29, 2009, 01:24 PM

Why is a .44 Mag a .44 when the bullets are .429?..........

CowTowner · May 29, 2009, 01:26 PM

Or a .38 Special a .38 when the bullets are .357 in diameter?

Nate1778 · May 29, 2009, 01:34 PM

Absolutely, I am simply trying to figure out why they do this. Didn't know if there was some ole tradition to it, or it was a thing decided late night at the bar.

Jim Watson · May 29, 2009, 01:36 PM

Because .380 ACP sounded better to the catalog writer than .355 ACP?

azredhawk44 · May 29, 2009, 01:37 PM

A holdover from measurement standards.

The outside of the case is .380 in diameter.

noelf2 · May 29, 2009, 02:10 PM

Quote:

The outside of the case is .380 in diameter.

No it's not. It's .374 on one end and .373 on the other. Also, a 32 acp and 32 S&W is closer to .31 than .32 (usually).

It's interesting to note that 380auto, 38special, 357magnum, and 9mm luger all have bullet diameters that only span a couple thousandths in difference.

Sevens · May 29, 2009, 05:33 PM

".38 caliber" truly was formerly a .38" bullet because it was a heeled bullet, like a .22LR is these days. (take apart a .22LR if you don't know what I mean)
It was a bullet that was held in the brass by a rounded heel, but the bullet itself that made contact with the bore did not sit inside the case, it was the same outside diameter as the cartridge case.

As the ".38" evolved, the bullet got smaller and it sat fully inside the case and became the .356-.357" projectile that we know now. Still, though, it's called a ".38" even though it doesn't measure that way anymore.

I think the ".380" was just a way of giving folks the idea of a ".38" but a different caliber.

There are many other examples of this kind of twisted logic in cartridge names. Some of it gets lost in translation over the years. Some other calibers are all-out marketing hype with little logic behind it. Think of it as shooter trivia and have fun with it!

PLEASE NOTE: This is the foggy memory that I have of how .38 that we know it evolved from a real .38 in to the .357 that we measure today, but some of my details are MY OWN interpretation of what I remember. And my theory on why .380 is called .380 is my guess only. Don't take ANY of this as gospel. There's a good chance someone who knows this stuff much better will post more accurate information. In the mean time, that's how I remember it.

rwilson452 · May 29, 2009, 06:22 PM

Now if you go over to Europe the .380 becomes the 9mm Kurtz. Kurtz is German for short.

Randy 1911 · May 29, 2009, 06:51 PM

Quote:

Or a .38 Special a .38 when the bullets are .357 in diameter?

Sevens answered this one right.

El Paso Joe · May 30, 2009, 08:39 PM

With all respect, I do not think that Sevens got it right. A heeled bullet like the .22 rimfire or the .310 Cadet Martini fit inside the case with the base of the bullet smaller than that outside the case. The .310 is really a .32 if you slug the bore. This the case with heeled bullets - the heel is less than the bore. So if the 38 were named as a heeled bullet it would be called a .357 - that measured .38 if the bore were slugged. Heeled bullets were more of a European thing and their mindset was different from the Americans hence the difference in designations.

But the .22 is the diameter not of the base but the larger part outside the base. Go figure...

Many .310 Cadet Martinis were re-chambered for the 32-20 which absolutely will not preform. The 32-20 is really a .31. And it is not heeled.

Personally I don't try to make much sense of the designations for more than marketing purposes... As long as the label on the box of ammo matches the barrel, you will be (more or less) ok.

B.L.E. · May 30, 2009, 09:08 PM

And just to add to the confusion, the .38-40 is really a .401.

Sky Master · May 30, 2009, 10:00 PM

A .38-40 is a 40 caliber bullet ahead of 38 grains of black powder. Backwards in naming from other calibers. 44-40, 45-70, 30-40 KRAG, 30-30 ect ect

dmazur · May 30, 2009, 10:15 PM

Or, the .280 Remington, which was renamed 7mm Express Remington in an effort to boost sales. Later, since this was confused with the 7mm Remington Magnum, Remington renamed it again, back to .280 Remington.

Are these two 7mm diameter? Nope, more like 7.2mm. Are they .280" diameter? Nope, .284" is more like it.

There are dozens of examples like this, where cartridge names have little to do with their bullet diameter. As far as I know, there is no universal naming scheme that can be used to predict when the cartridge name is "true" to diameter and when it isn't. It's a mess.

David Wile · May 30, 2009, 11:08 PM

Hey folks,

Here's another one: I think the standard cast bullet size for original .36 caliber black powder revolvers is actually .375. I still have a Navy .36 that had slightly larger chambers, and I bought three double cavity moulds from Lyman before I got one that dropped round balls slightly larger than the other two moulds. With a .375 bullet, why would they call it a .36 caliber? And to further muddy the water, consider then that the .36 caliber bullet is actually bigger than the .38 caliber bullet. I know not why; I just go along for the ride.

Best wishes,
Dave Wile

May 29, 2009, 12:47 PM	#1
Nate1778 Senior Member Join Date: January 21, 2009 Location: Louisville Ky Posts: 312	Why is a .380 a .380? Don't know if this is the right forum for this but can someone explain how this came about. I have Wiki'ed the subject with no answer. If the bullet is .355-.356 where did the .380 come from? Just bugged me since my last order of bullets arrived. __________________ "And finally, the Baby Bear looked and he said, "Somebody's sleeping in my bed, and the bastard's still there!" But Goldylocks had a Remington semi-automatic, with a scope and a hair-trigger!"

May 29, 2009, 01:24 PM	#2
rantingredneck Senior Member Join Date: January 12, 2007 Location: North Carolina Posts: 4,728	Why is a .44 Mag a .44 when the bullets are .429?.......... __________________ NRA Member NC Hunter's Education Instructor PCCA Member (What's PCCA you ask? <- Check the link)

May 29, 2009, 01:26 PM	#3
CowTowner Senior Member Join Date: October 17, 2007 Location: Cowtown of course! Posts: 1,747	Or a .38 Special a .38 when the bullets are .357 in diameter? __________________ NRA Chief Range Safety Officer, Home Firearms Safety, Pistol and Rifle Instructor *“Today, we need a nation of Minutemen, citizens who are not only prepared to take arms, but citizens who regard the preservation of freedom as the basic purpose of their daily life......”* President John F. Kennedy

May 29, 2009, 01:34 PM	#4
Nate1778 Senior Member Join Date: January 21, 2009 Location: Louisville Ky Posts: 312	Absolutely, I am simply trying to figure out why they do this. Didn't know if there was some ole tradition to it, or it was a thing decided late night at the bar. __________________ "And finally, the Baby Bear looked and he said, "Somebody's sleeping in my bed, and the bastard's still there!" But Goldylocks had a Remington semi-automatic, with a scope and a hair-trigger!"

May 29, 2009, 05:33 PM	#8
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	".38 caliber" truly was formerly a .38" bullet because it was a heeled bullet, like a .22LR is these days. (take apart a .22LR if you don't know what I mean) It was a bullet that was held in the brass by a rounded heel, but the bullet itself that made contact with the bore did not sit inside the case, it was the same outside diameter as the cartridge case. As the ".38" evolved, the bullet got smaller and it sat fully inside the case and became the .356-.357" projectile that we know now. Still, though, it's called a ".38" even though it doesn't measure that way anymore. I think the ".380" was just a way of giving folks the idea of a ".38" but a different caliber. There are many other examples of this kind of twisted logic in cartridge names. Some of it gets lost in translation over the years. Some other calibers are all-out marketing hype with little logic behind it. Think of it as shooter trivia and have fun with it! PLEASE NOTE: This is the foggy memory that I have of how .38 that we know it evolved from a real .38 in to the .357 that we measure today, but some of my details are MY OWN interpretation of what I remember. And my theory on why .380 is called .380 is my guess only. Don't take ANY of this as gospel. There's a good chance someone who knows this stuff much better will post more accurate information. In the mean time, that's how I remember it. __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

May 29, 2009, 01:36 PM	#5
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,543	Because .380 ACP sounded better to the catalog writer than .355 ACP?

May 29, 2009, 01:37 PM	#6
azredhawk44 Junior member Join Date: September 28, 2005 Location: Mesa, AZ Posts: 6,465	A holdover from measurement standards. The outside of the case is .380 in diameter.

May 29, 2009, 06:22 PM	#9
rwilson452 Senior Member Join Date: June 10, 2004 Location: Tioga co. PA Posts: 2,647	Now if you go over to Europe the .380 becomes the 9mm Kurtz. Kurtz is German for short. __________________ USNRET '61-'81

May 30, 2009, 08:39 PM	#11
El Paso Joe Senior Member Join Date: July 4, 2006 Location: Spokane Valley Posts: 340	With all respect, I do not think that Sevens got it right. A heeled bullet like the .22 rimfire or the .310 Cadet Martini fit inside the case with the base of the bullet smaller than that outside the case. The .310 is really a .32 if you slug the bore. This the case with heeled bullets - the heel is less than the bore. So if the 38 were named as a heeled bullet it would be called a .357 - that measured .38 if the bore were slugged. Heeled bullets were more of a European thing and their mindset was different from the Americans hence the difference in designations. But the .22 is the diameter not of the base but the larger part outside the base. Go figure... Many .310 Cadet Martinis were re-chambered for the 32-20 which absolutely will not preform. The 32-20 is really a .31. And it is not heeled. Personally I don't try to make much sense of the designations for more than marketing purposes... As long as the label on the box of ammo matches the barrel, you will be (more or less) ok.

May 30, 2009, 09:08 PM	#12
B.L.E. Senior Member Join Date: December 20, 2008 Location: Somewhere on the Southern shore of Lake Travis, TX Posts: 2,603	And just to add to the confusion, the .38-40 is really a .401.

May 30, 2009, 10:00 PM	#13
Sky Master Senior Member Join Date: May 30, 2009 Posts: 136	A .38-40 is a 40 caliber bullet ahead of 38 grains of black powder. Backwards in naming from other calibers. 44-40, 45-70, 30-40 KRAG, 30-30 ect ect

May 30, 2009, 10:15 PM	#14
dmazur Senior Member Join Date: July 5, 2007 Location: Pacific NW Posts: 1,310	Or, the .280 Remington, which was renamed 7mm Express Remington in an effort to boost sales. Later, since this was confused with the 7mm Remington Magnum, Remington renamed it again, back to .280 Remington. Are these two 7mm diameter? Nope, more like 7.2mm. Are they .280" diameter? Nope, .284" is more like it. There are dozens of examples like this, where cartridge names have little to do with their bullet diameter. As far as I know, there is no universal naming scheme that can be used to predict when the cartridge name is "true" to diameter and when it isn't. It's a mess. __________________ .30-06 Springfield: 100 yrs + and still going strong

May 30, 2009, 11:08 PM	#15
David Wile Senior Member Join Date: June 14, 2001 Location: Mechanicsburg, PA Posts: 585	Hey folks, Here's another one: I think the standard cast bullet size for original .36 caliber black powder revolvers is actually .375. I still have a Navy .36 that had slightly larger chambers, and I bought three double cavity moulds from Lyman before I got one that dropped round balls slightly larger than the other two moulds. With a .375 bullet, why would they call it a .36 caliber? And to further muddy the water, consider then that the .36 caliber bullet is actually bigger than the .38 caliber bullet. I know not why; I just go along for the ride. Best wishes, Dave Wile