They say there no stupid questions, so. I have always wondered why they call it .38 caliber when the bullet is .357 diameter? Round it to .36 would make more sense. The old Colts were .36 cal. Anyway, just curious.

__________________
No baby we aint

I'm guessing it was probably marketing.

The BRASS is .379 so calling it a .38 based on the diameter of the brass has a certain validity but still makes it sound bigger and better than calling it a .36

__________________
Send lawyers, guns & money...

The .38 Long Colt has a heeled bullet, like the .22 rimfires. It was the same diameter as the case. It was outside lubricated.
The later Special is basically the same case with a smaller inside lubricated bullet.

__________________
and what his trumpet saith

This is correct. They reduced the bullet diameter to accommodate the inside lubricated "technology". The rest was marketing. A ".36" would seem inferior to ".38". People were used to .38.

The same thing happened to the .44 Special.

Hey!! I just learned something.
thank you.

And the mighty .44 Magnum is .429.

__________________
Only a cold warrior

Thanks guys! The combined wisdom of this site is outstanding.

__________________
No baby we aint

True, but the responses so far have been totally incomplete in answering your original question. Here is the whole story.

The original .38 Caliber cartridges were the .38 Short and Long rim-fire intended for the breech-loading conversions of the Colt, Remington, etc. .36 cal. percussion revolvers**. Bullet diameter of these rim-fire cartridges was .377-.379", very legitimately called .38 caliber. When these cartridges were eventually up-graded to center-fire configuration with heel-based bullets of the same diameters the .38 designation stuck.

Eventually the center-fire cartridges were further improved to use of inside-lubricated bullets of .357 nominal diameter the .38 caliber designation was thoroughly established, and finally barrel groove diameter was reduced to .357" to match the ammunition. The final iterations of this progression of cartridges was the .38 Special and .357 Magnum!

So, even though the .38 Long Colt is commonly cited as being the parent cartridge to the .38 Special, the truth is the .38 Short and Long rim-fires are truly the great-great great grand-parent cartridges of the .38 Special and later developments that followed.

NOW you really know why the .38 Special is called a .38!!

__________________
Gunsmithing since 1961

But why is a .38-40 a .400 bullet?

__________________
Psalm 27:2

The reason for that is probably lost somewhere in the archives of the Winchester Repeating Arms Company's marketing department.

Perhaps they felt .40-40 was confusing and too close to it's big brother the .44-40? It was originally introduced for rifles and I'm not sure what the competitive landscape looked like in the lever action rifle market in 1874.

I've never heard an explanation for that one. Some things remain a mystery.

To further muddy the waters, the 38/40 Takes a .401 bullet,as stated, and the 44/40 is actually a .427. Think I’ll stick with the good ol’ honest .45.

As others have pointed out above, many of the early cartridges accepted heeled bullets (reduced diameter bullet body to fit into the cartridge case, larger diameter forward portion to fit the bore and groove diameters).

The ..38-40 utilized a different approach, having a smaller diameter lead bullet with hollow base intended to open up to seal the bore and grooves upon firing.

The .38-40 cartridge was originally called .38 Winchester Center Fire (WCF), while same case with .44 bullet was known as the .44 WCF. Original loadings of both utilized cast lead bullets somewhat smaller in diameter than the (then standardized) bore and groove diameters.

Later on in the decades of cartridge developments other manufacturers started chambering firearms for the Winchester-developed loads. Some used marketing terms featuring their own company's name, some simply wished to avoid promoting a competitor's name (Winchester), perhaps some wished to avoid claims of copyright infringements. Regardless of the specific reason, these two cartridges became commonly known as the .38-40 and .44-40, terms which identified the nominal caliber and the original weight of black powder charge (40 grains).

Similarly, Winchester's developments for the smaller-framed rifles (.25 WCF, .32 WCF) became more commonly known as the .25-20 and .32-20 as they gained popularity and general use among a number of firearms manufacturers.

Prior to about the early-1910's most of the major firearms companies stuck with their own proprietary cartridge designs. Colt, Marlin, Sharps, Winchester and others all offered a variety of cartridges, and few offered any chamberings other than their own. This created confusion in customers' minds, generated debates over the relative merits (accuracy, killing power, etc) of various makers' offerings, and vastly complicated supply lines (especially in remote areas). Custom gunsmiths were offering rechambering services to "improve" one maker's rifle by chambering it for another maker's cartridge.

All in all, it was a challenging and confusing time period for everyone involved. By the very early 20th Century the move was on for more standardization of cartridge designs, rifle chambers, bore diameters, and other aspects of the business. Some manufacturers continued making the earlier proprietary cartridge designs to serve their customers, some designs passed into history and owners of some firearms had the choice of abandoning use or having the rifle altered to an available cartridge (a process that led to even more problems along the way).

Also, the old New Model 3, 32-44 (and the .320 Revolving Rifle) were true 32 calibers at .323". The later .32 S&W Long is .312".

__________________
ANTIQUESMITHS
LM1300 SWHF425

...and the .36 caliber cap and ball revolver originated the caliber for the later .38 rimfire cartridges.

Jupiter 1,
Had you read my entire post you would have seen this was explained thoroughly already.

HKCavalier,

.38-40?

Even Charles Suydam (U.S. Cartridges and Their Handguns; Bienfeld Publishing, 1977) doesn't even venture an explanation for the .38-40 designation. I have always felt glenwold's explanation, "Perhaps they felt .40-40 was confusing" is the most likely explanation.

__________________
Gunsmithing since 1961

It's the one that bucks the trend. Most caliber designations seem to err larger, as pointed out in other posts.

__________________
Psalm 27:2

It only gets better.

We have the 7,63 Mauser, the 7,65 Parabellum and the 7,62 Tokarev.

Those calibers use the exact same bullet diameter.

__________________
Expect the unexpected

A 38 s&w is .360. My lead boolits for revolvers are .358. I bought 1000 .357 gas checks on Gunbroker but when they got here they were .375s.

The nomenclature of ammo , both foreign and domestic ...but especially American naming , is extremely confusing .
A book , Cartridges or the World , helps explain some of the confusion .
The bottom line is in the USA there is no set standard .
The 41 magnum is correct with a .410" diameter bullet but after that it's pretty much what the developer wants to call it ...
There is no rhyme and very little reason to the whole affair !
Gary

__________________
Certified Cajun
NRA Member

I always wondered why if the 30-30 was such a big hit in marketing what the problem would have been with a 40-40 ... it sounds just fine to my ears ...another mystery of life !

__________________
Certified Cajun
NRA Member

Wikipedia provides a concise explanation:
"Many shooters wonder why a .38 caliber firearm actually shoots bullets of diameter .357 inches, and a .44 caliber firearm shoots .429-inch-diameter (10.9 mm) bullets. In both of these cases, the name of the caliber derives from older heeled-bullet designs, and the name was kept even when the bullet was shrunk to fit inside the case. The .38 S&W cartridge, for example, dates from 1877 and has a nominal outside case diameter of .380 inches, while the inside of the case is .360 inches.

Older .38 caliber cartridges, like the .38 Short Colt, did use a heeled bullet, so rather than create a new ".35" or ".36 caliber", Smith & Wesson kept the designation ".38" even though it no longer accurately reflected the groove diameter. The later .38 Special continued the trend, and even automatic pistol cartridges like the .38 Super and .380 ACP retained the .38 caliber designation, even though they were .357s. This continued until 1935 and the introduction of the .38 Special-based .357 Magnum cartridge. The newer (1956) .44 Magnum, however, retained the designation of its parent .44 Special cartridge, even though it fired a .429 inch bullet. The legacy of heeled bullets is the cause of confusion among many shooting enthusiasts over the actual physical diameters of the bullets they fire in their guns."

So far as I know, the only cartridge made today that retains a heeled bullet is the .22 RF, but it is possible that there are others still made in remote areas of the world. I have read that the Russians originated the idea of using inside lubricated bullets for CF revolver cartridges - the .44 Russian.

I could be wrong but didn’t they use to measure the grooves in the barrel different also. That’s why a 44 colt black powder uses .45 balls ?

__________________
Bobby SWCA #4067
SWHF #1144

As a general rule, C&B revolvers use balls which are larger in diameter than the barrel groove diameter, because they must be swaged into the revolver cylinders in order to form a tight seal. For example, .36 caliber C&B revolvers normally use .375" balls. Same is true for .44 caliber C&B revolvers, I think they normally use something like .452" balls.

Firing Mini-balls that had to be a slip fit into muzzle loaders the military was accustomed to naming rifles by their land diameter. Consequently they named the .45-70 which is actually close to .46 caliber a .45 and named our military's .30 caliber rifles which actually have groove diameters close to .31 caliber .30 caliber. Sporting .45 and .30 caliber rifle cartridges stick with that practice so most .45 and .30 caliber rifle cartridges also buck the trend of cartridges being named a number larger than their bullet diameter. There are exceptions. .460 Weatherby comes to mind.

I will venture a logical guess as to why Winchester might have named .38 WCF .38. Perhaps Winchester wanted to profit off the good selling gun name .38 but in 1874 it did not appear practical to neck down .44 WCF all they way to .38 caliber. The parts to feed smaller diameter .32-20 cartridges through the 1873 rifle were still off in the future.

It was to confuse us that are over 70.

...as long as it can't be confused with another cartridge, which has happened at times anyway, especially with several names for the same cartridge.

How many times has somebody bought .38 Special to put i a .38 S&W?

__________________
"He was kinda funny lookin'"