# clueless about ammo, how to understand bullet size?



## Colt45

new to guns, how does one determain how big in diameter and the length of a bullet?
is there something in the name im missing? or do you just have to study and remember what takes what? for example:
357
38 special.
9mm
380

i know all these are somewhat simular, but what exactly is the difference? i dont understand why they just can't go by the caliber size, like 22cal, 44cal,45cal etc..

is there a sizing chart or something?


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## jeffreybehr

Colt, seems caliber designations are as logical...NOT...as overall cartridge designations. Where oh where did anyone get '.38' out of a bullet diameter of 0.357"?

There's no magic--you just have to find a reloading manual online and look at the bullet-diameter specification.

And there's not much logical about your examples of calibers, either, with bullet diameters of 0.224" and 0.430" (NOT 0.44"!!!). Only the .45-caliber's bullet diameter of 0.452" rounds to its designation of .45.


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## SaltyDog

Colt45 here is a link that will help to explain the basic differences in the most popular handgun calibers. Also if you do a Google you'll see a number of web sites explaining the differences.

http://www.outdoors.net/site/features/feature.aspx+Forum+Firearms+ArticleCode+2602+V+N+SearchTerm+

Be careful. Only shoot ammunition that the handgun is designed for. READ THE MANUAL. For instance do not shoot 9mm Luger 9 x 19 in a gun intended to shoot 9mm Makarov 9 x 18. There are slight differences that can make shooting improper ammunition hazardous to your health.


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## bruce333

> Be careful. Only shoot ammunition that the handgun is designed for. ...
> There are slight differences that can make shooting improper ammunition hazardous to your health.


This is the most important thing you need to keep in mind. Just because a round might fit in a gun doesn't mean it is safe to fire it.

http://www.corneredcat.com/Ammunition/caliber.aspx


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## Cybrludite

jeffreybehr said:


> Colt, seems caliber designations are as logical...NOT...as overall cartridge designations. Where oh where did anyone get '.38' out of a bullet diameter of 0.357"?


Back in the black powder days, many handgun cartridges used what are known as heeled bullets. This means that the bullet was the same diameter as the outside of the case, with a slightly sub-caliber "heel" inside the case. .22 Short/Long/Long Rifle still use this sort of bullet. When the switch was made to having the bullet being the same size as the case's inside diameter, it was cheaper to replace the barrel boring machines than the brass case manufacturing gear. For marketing purposes the old cartridge size names stayed on, hence .38 Special uses a .357" diameter bullet, since that's the ID of the case. The OD is around .38". If that was clear, let me know & I'll start over... :mrgreen:


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## Steve M1911A1

Colt45 said:


> new to guns, how does one determain how big in diameter and the length of a bullet?
> is there something in the name im missing? or do you just have to study and remember what takes what? for example:
> 357
> 38 special.
> 9mm
> 380
> 
> i know all these are somewhat simular, but what exactly is the difference? i dont understand why they just can't go by the caliber size, like 22cal, 44cal,45cal etc..
> 
> is there a sizing chart or something?


• Both .357 Magnum and .38 Special use the same diameter bullet: 0.357".
• However, the .38 S&W uses a larger-diameter bullet.
• Both the 9mm Parabellum ("Luger") and .380 ACP (9mm Kurtz) use bullets 0.355" in diameter.
• Given the bullet diameter as a constant, different bullet weights are achieved by using longer or shorter bullets. Thus a .38 Special, 125-grain bullet would be shorter than a .38 Special, 158-grain bullet. (This is only generally true, since another way would be to change the bullet's shape: a .38 Spl., 158-grain bullet might be blunter-ended than the 125-grain version.)


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## chris441

Here is a site I found awhile back when I was trying to figure all of this out.

It will show you everything you want to know in size, dimensions, etc.
http://www.genitron.com/Basics/Cartridges.asp


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## hideit

notice even the 44 special and 44 magnum are not .44" dia
i think it is closer to .43


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## BowhuntnHoosier

Yep just have to do some studying and figure it all out. I really hate the 9X18 Makarov.


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