Ammo Caliber Rookie Question

[Legallyme88]

Ok. I looked through the forum and couldnt find an answer so either
A) I missed it and I apologize for reasking a question or,
B) This is the most rookie question no one needed to ask lol

I am slightly confused about ammunition calibers. I have done research and I understand that its the measurements to properly fit in the barrel. However, I guess where I get confused is with the 9m. A .380 is smaller than a 9m but a .45 is bigger than a 9. Talking mathematically since the .380 and the .45 are behind decimals they would be smaller than a whole number. So yeah if anyone could please help me with understanding this and once again sorry for such a rookie question.

Thanks in advance

[mk4]

.22lr, .32, .357mag, .38, .40s&w, .44mag, .45acp are all in 'inches'.
9mm is 'millimeters'. there are 25.4 mm per inch, so your 9mm is .354"

hth.

[Legallyme88]

Ok. Thank you so much. That makes much more sense to me now.

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[dorminWS]

.22lr, .32, .357mag, .38, .40s&w, .44mag, .45acp are all in 'inches'.
9mm is 'millimeters'. there are 25.4 mm per inch, so your 9mm is .354"

hth.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Yup. To put a finer point on it:

Bullets whose diameter is expressed as "mm" are merely in metric units. Bullets whose diameter is expressed as "caliber" are expressed in tenths, hundreds and thousandth of an inch. .22 caliber is twenty-two hundredths of an inch. .223 caliber is Two hundred twenty-three thousandths of an inch.

So, to convert millimeters (mm) to inches (caliber), divide the number of millimeters by 25.4; just as the previous poster said. (to convert 9mm ti "caliber", the calculation is 9mm/25.4mm = .354)

Caliber is just the decimal portion of an inch that is equal to the diameter of the bullet; which is why calibers are properly written proceeded by a decimal. To convert inches (caliber) to millimeters (mm), multiply the caliber (decimal portion of an inch) by the number of millimeters (mm) in an inch. or 25.4. (to convert .45 cal to millimeters, or mm, the calculation is .45 x 25.4 = 11.4mm)

[mk4]

Ok. Thank you so much. That makes much more sense to me now.

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'welcome, Jessy.

[jdonovan]

I am slightly confused about ammunition calibers. I have done research and I understand that its the measurements to properly fit in the barrel. However, I guess where I get confused is with the 9m. A .380 is smaller than a 9m but a .45 is bigger than a 9. Talking mathematically

Well we also have the difference measurements. Some parts of the world like to measure the 'small' axis across the bore.... i.e. land-to-land. Other places measure the long axis i.e. grove to grove.

The you get the marketeers involved.

A 38 special and a 357 magnum are the exact same in all dimentions except the 357 case is 1.290 long vs 1.115 for the 38 so you can't put the high-powered case into the lower powered gun... but the revers is fine.
And the projectile for both is a .357, even tho the 38 special came to market first.

.45 long colt, .454 casull, and 460 S&W. All shoot a .454 diameter projectile.


The takeaway from all of this is the listed caliber, gives you a ROUGH approximation of the bore, but that's about it.

[Chasbo00]

A 38 special and a 357 magnum are the exact same in all dimentions except the 357 case is 1.290 long vs 1.115 for the 38 so you can't put the high-powered case into the lower powered gun... but the revers is fine.
And the projectile for both is a .357, even tho the 38 special came to market first.

Why it's called a .38 Special rather than a .36 Special...


heeled bullet is on right - today, the .22 Long Rifle cartridge still has a heeled bullet

"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 to 1877 and has a nominal outside case diameter of .380 inches, while the inside of the case is .357 inches. Older .38 caliber cartridges, like the .38 Long Colt, did use a heeled bullet, so rather than create a new ".35" or ".36 caliber", Smith and Wesson kept the designation ".38" even though it no longer accurately reflected the bore 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."

http://en.wikipedia.org/wiki/Heeled_bullet

[Legallyme88]

Wow! I know more now about calibers than I ever thought possible! Thank you for all the valuable information. I love you all on here such a wealth of knowledge.

[rromeo]

A .38 is the same size bullet as a .357, and both are bigger than a .380 which is really .355
Got it?

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[jdonovan]

and a 45-70 is a 458 and doesn't use 70 grains of powder anymore.

We could go on like this almost forever =)

[Diomed]

It's enough to make the metric system look attractive.

[WRW]

7.62-06 Doesn't have much of a ring to it.

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[dorminWS]

7.62-06 Doesn't have much of a ring to it.

.........................................

Neither does "Colt 11.43"

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[WRW]

7.62-06 Doesn't have much of a ring to it.

.........................................

Neither does "Colt 11.43"

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LOL!! Headline: MAJOR MALT LIQUOR MANUFACTURER DECLARES BANKRUPTCY AFTER CONVERSION TO METRIC SYSTEM!!!