Caliber confusion

[Tackdriver]

Excuse me if this has been beat to death in the past, I did a search and didn't come up with much.

I suffer from caliber confusion, how is it a .45acp is a lighter round than a .44? Math/common sense leads me to believe a .45 is larger, is cart. length difference?

Then there's a .357mag and a .38, seems to me .38 is larger than .357?
Then there's a .357sig?

What's the difference between a .38 and a .380?

I know the .357sig and .380 are auto rounds why a new cart. designation for an automatic?

These are only a few examples of the many, am I just wasting time trying to make sense of any of it? Any light someone could shed would be great.

 

[Rabid Rabbit]

A lot of it is Marketing garbage, other names avoid confusion, europe vs us naming convention, horsepower etc... get a copy of cartridges of the world and all will be made clear.

 

[foghornl]

A lot of the calibers are just names....

F'rinstance, the .44Mag cartridge uses a .429-.431 nominal diameter bullet

.357Mag and .38Spl are both nominally .355-.357 in diameter.

Not sure about diameter, but the .380 Auto is a short rimless cartridge case.

The .357Sig is a 'bottleneck' round, while MOST other handgun rounds are either straight-walled or gently tapered.

The .45ACP ammo is another 'short' case, made to run lower pressures than the .44Mag.

Cartridges can be a long-term study program all to themselves.

 

[TX1911fan]

Caliber typcially refers to the diameter of the bullet, but has little to do with the power. You have to look at the cartridge case as well to determine how powerful a round will be. Bigger doesn't always mean more powerful.

 

[Vern Humphrey]

how is it a .45acp is a lighter round than a .44? Math/common sense leads me to believe a .45 is larger, is cart. length difference?

First of all, the .45 Colt, a revolver cartridge was developed in 1873, a black powder cartridge, and the early guns were made of wroght iron, not steel. Therefore pressures are held very low (around 14,000 PSI).

Even so, the early .45 Colt was quite a handful, and the Army liked the shorter, less powerful .45 developed for the Smith & Wesson Schoefield.

The .45 ACP was developed to duplicate the lighter .45 load in an automatic pistol.

The .44 Magnum is a 'stretched' version of the .44 Special, loaded to very high pressures (originally around 40,000 PSI.)

Ironically, in a strong revolver (like the Ruger Blackhawk) the .45 Colt can be loaded to levels slightly higher than the .44 Magnum.

Then there's a .357mag and a .38, seems to me .38 is larger than .357?
Then there's a .357sig?

The early .38s used "heeled" bullets, with a reduced diameter base that fit inside the cartridge case. Most of the bullet was the same size as the outside of the cartridge case. This meant the lubrication was exposed, which was not a good idea. Later on, the bullet size was reduced, so it could be loaded deeper in the case, with the lubrication grooves below the mouth. As a result, .38s became .36s, more or less. The .357 Magnum is simply a .38 Special lengthened slightly and loaded to much higher pressures.

What's the difference between a .38 and a .380?

The ".38" designation is traditionally assigned to revolvers (with a notable exception or two.) The .380 is actually a short 9mm and uses a .355 diameter bullet. In Europe it is often called the 9mm Kurz (short) or 9X17 (meaning a 9mm bullet in a case 17 mms long.)

I know the .357sig and .380 are auto rounds why a new cart. designation for an automatic?

The .357 Sig is a necked down .40 (which is a shortened 10mm)

By and large, rimmed cartridges work best in revolvers (the ejector star works against the rims when you eject the cases.) But rims aren't all that good in box magazines -- the rims can interlock and jam the gun. So automatics mostly use rimless cartritges.

 

[woof]

Adding to what's been said, you may be overlooking bullet length. Length is why a .30 caliber bullet, say for .30-06, can be from 100 grains to well over 200 grains in weight.

 

[spwenger]

Wrought Iron?

Iron ore is generally composed of some form of iron oxide (rust). At least in the older versions of steelmaking, the iron ore is initially combined with an excess of carbon (in the form of "coke," which is coal with its volatile components driven off with heat) in a process that removes the oxygen that formed part of the oxide. This results in pig iron. Iron, as I recall, contains relatively large inclusions of carbon. There are forms of iron which have desirable properties for some applications but lack the tensile strength and flexibility of steel.

When steel is made from iron, it is melted in the presence of oxygen, to burn off the excess carbon, creating an alloy of iron and carbon, along with any other elements (such as nickel, chromium, molybdenum, etc.), which may be added to confer special properties. To my knowledge, no American firearms as modern as cartridge revolvers have been manufactured of iron, wrought or any other kind. ("Wrought iron," according to the American Heritage Dictionary, is " An easily welded and forged iron that is a mechanical mixture of refined metallic iron with 1 to 3 percent siliceous slag." It is usually used for decorative grillework.)

Steelmaking, like many other manufacturing processes, underwent tremendous advances in the 20th centrury so that steels used in firearm manufacture became stronger and more reliable. This is why the original .357 Magnum revolvers were built on S&W's large N frame and it was not until the 1950's that S&W felt confident about making a .357 magnum revolver on the smaller K frame.

Not only were 19th-century steels weaker than most of today's, there was no need to design revolvers to handle the higher pressures generated by smokeless powders when smokeless powders had not even been developed (e.g., 1873).

I am not trying to disparage anyone with this comment but it's helpful to be sure of your terminology.

 

[Vern Humphrey]

There are forms of iron which have desirable properties for some applications but lack the tensile strength and flexibility of steel.

And the early Colts used iron, not steel. Steel was not widely used in America until the late 1870s -- earlier, most steel was imported from England.

 

[Bazooka Joe71]

Do yourself a favor, and just look at most calibers as names and not measurements, otherwise your head will start spinning.

Don't even get me started on the 7.62's


Vern, thanks a lot...Now my head is spinning again.

 

[Tackdriver]

Thanks Vern, that's the info I was looking for.

 

[Tackdriver]

Do yourself a favor, and just look at most calibers as names and not measurements, otherwise your head will start spinning.

That my be the best advice

 

[JesseL]

There is a relatively short list of bullet diameters common to most cartridges. To differentiate the different cartridges, they will often be given names that slightly fudge the numbers.

.224" > .22 Hornet, .220 Swift, .221 Fireball, .222 Remington, .223 Remington, .224 Weatherby, .225 Winchester, etc.


Some cartridge names derive from the cap-and-ball black powder days and the transition from loose powder and balls to heeled bullet cartridges, to inside lubricated bullets.

Such was the case with todays ".38" calibers. Back in the 1800's many revolvers used .375" balls. When these guns were converted to fire cartridges, they used bullets and cases that were the same .375". These bullets had a smaller diameter at the rear (called a heel) in order to fit inside the case, and exposed lube grooves further forward on the bullet. When the exposed lube began to prove messy, they started making the whole bullet the same diameter as the inside of the case (.357") and putting the lube grooves down where they would be protected by the case. Ideally these bullets were supposed to be expanded by the force of firing so they would still seal against the (.375") bore of the gun, but it didn't really work that well and accuracy suffered. So the next step was to reduce the size of the bore to match the bullets being used, and that's how we got all these ".38" cartridges that are really .355-.357". Nobody wanted to make it sound like they were going to smaller guns until someone in the 1930's decided ".357 Magnum" had enough appeal to negate the problem.

 

[Vern Humphrey]

.224" > .22 Hornet, .220 Swift, .221 Fireball, .222 Remington, .223 Remington, .224 Weatherby, .225 Winchester, etc.

You can add .218 Bee and .219 Zipper to the list. All are .224s except the early Hornets, which were built on M1922 Springfields, and used the .223-diameter .22 LR barrel.

 

[Gator]

If you really want to get confused look into the .455, .450, .476 British handgun cartridges

 

[enkindler]

Re: 38 vs 357

One refers to the land dimensions, the other the groove dimensions IIRC.

 

[Jimmy Newman]

Actually, .357 is the dimension from groove-to-groove, which is generally used in the United States and is larger than the land-to-land measure, which is used in metric designations.

For .38 Special, the .38" measure is actually the diameter of the brass case.

 

[pax]

See here: www.corneredcat.com/Ammunition/caliber.aspx

pax

 

[Threeband]

Get yourself a copy of Cartridges of the world
(http://www.amazon.com/Cartridges-World-11th-Frank-Barnes/dp/0896892972/ref=pd_bbs_sr_1/104-3697835-9703164?ie=UTF8&s=books&qid=1190688444&sr=8-1)

Great reading!

And remember, a 2x4 isn't 2" x 4".

 

[Sharps Shooter]

"And remember, a 2x4 isn't 2" x 4"."

Very good comparison Threeband.
I too recommend "Cartridges Of The World" and reading the definition of the word "caliber" as stated in the glossary of many reloading manuals.

 

[default]

I'm hardly an expert, but if you take into account bullet diameter and weight, and consider cartridge length, and the velocity the bullet is propelled to, it starts to make more sense. Unfortunately, many calibers have uninformative or misleading names.

For example, one might conclude that .50bmg is only marginally more powerful than .45acp, since the bullet isn't even 10 percent greater in diameter. However, look at it this way: .45acp (which could also be called 11.4x23mm) pushes a 230-grain bullet to 900 feet per second. .50bmg (which is really impressive-sounding when rendered in metric - 12.7x99mm!) can push a 700-grain bullet to nearly 3000 feet per second.