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Discussion Starter #1
I am confused on what we are measuring, like I know a .45 is larger then a .40... and the.40 is larger then the 9mm but the bullet is not 31 times smaller. I know I should know this by this point in my gun collecting time, but it has slipped by me. I know how the calibers line up a 22 to a 22 mag to what a 25? then to the 380 to the 9 to the 40 to the 45 and a few in between. But what does it all mean?
 

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I understand it but probably not enough to explain it clearly. I think I'll let somebody else chime in.



Krackels
 

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All of the "major" numbers (.22, 9mm, .40) represent the bullet's outside diameter (OD). Unfortunately, the numbers are often arbitrary or contrived. A .223 NATO is actually .224" OD, and a .38 Special is really the same diameter as a 357 Magnum (.357").

The reference to "major" numbers involves rifle calibers, which are often followed by another number that is generally irrelevant to bullet size. See the following examples:
.30-06 - .30 caliber (.308" OD), year 1906
.22-250 - .22 caliber (.224" OD), based on a necked-down .250-3000 Savage case
.250-3000 - .25 caliber (.257" OD), 3000fps

Got the idea?
 

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Any mm bullets, 9mm and 10mm for instance, are metric. And the grain # on the box is the weight of the bullet. I'm guessing that most ammo companies won't publish the type and weight of powder in a given shell. I think it's like a secret recipe.

Krackels
 

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stealthsniper said:
All of the "major" numbers (.22, 9mm, .40) represent the bullet's outside diameter (OD). Unfortunately, the numbers are often arbitrary or contrived. A .223 NATO is actually .224" OD, and a .38 Special is really the same diameter as a 357 Magnum (.357").

The reference to "major" numbers involves rifle calibers, which are often followed by another number that is generally irrelevant to bullet size. See the following examples:
.30-06 - .30 caliber (.308" OD), year 1906
.22-250 - .22 caliber (.224" OD), based on a necked-down .250-3000 Savage case
.250-3000 - .25 caliber (.257" OD), 3000fps

Got the idea?
Actually I believe the caliber is the bore size of the barrel. That is why the bullet diameter is actually larger than the caliber.

Also there are many variations like a .45-70. It is a .45 with a 70 grains of black powder charge. The bullet wieght I use is 300 grains, but I have seen 410 grains.

Mostly it takes memory from use and reading to remember all of the different cartridges.
 

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Krackels said:
Any mm bullets, 9mm and 10mm for instance, are metric. And the grain # on the box is the weight of the bullet. I'm guessing that most ammo companies won't publish the type and weight of powder in a given shell. I think it's like a secret recipe.

Krackels
You hit on the nose.
 

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yourshoesareuntied said:
I always thought the grain was dealing with the amount of powder "the amount of ka-boom", dang I suck at my bullet smarts in a bad way.
Grain is just a unit of mass or wieght.

1 ounce(troy) = 480 grain
 

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The big thing to look for in handguns isn't so much the caliber (though smaller usually isn't better), but the bullet weight and the velocity.

Consider identical ammo except for bullet weight. A light bullet travels faster and farther, but will deflect easily (off of bone, glass, etc.) and will slow rapidly once it hits something (such as a body). A heavy bullet travels slower and therefore a shorter distance, but is prone to smashing through whatever is in the way.

The main reason to look at caliber is to get the correct ammo for the job at hand. No matter how fast a .22 cal. goes I would never hunt elephant with one. Also, I would never use a .50 cal. to hunt gophers. As far as self-defense goes, 9mm to .45 cal. is good for almost any situation. As long as the gun in question is controlable and comfortable for the shooter.
 

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nogoa said:
Actually I believe the caliber is the bore size of the barrel. That is why the bullet diameter is actually larger than the caliber.
Technically, you are correct. However, there is enough variation in bore diameters to make them arbitrary, too. Throw in groove depth and we've got one crazy set of variables, lol.

Also there are many variations like a .45-70. It is a .45 with a 70 grains of black powder charge. The bullet wieght I use is 300 grains, but I have seen 410 grains.
Obviously there are many different loads for a given caliber. I was simply trying to explain the origins of a few of the "something dash something" rounds. Thanks for the tidbit on the .45-70; I didn't know that one.
 

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Discussion Starter #13
I appreciate your responses, I am going to see if I can find a web page with a poster sized image displaying all the different calibers. I would like to buy one on that note. Every thing from handguns to riffles to shotguns, that would be cool to look at. If I do find one I will post the link
 

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yourshoesareuntied said:
I appreciate your responses, I am going to see if I can find a web page with a poster sized image displaying all the different calibers. I would like to buy one on that note. Every thing from handguns to riffles to shotguns, that would be cool to look at. If I do find one I will post the link
I was at Gander Mountain the other day and they were giving away all sorts of magazines for the different manufactures of the guns as well as the ammo. One of the ammo ones was a fold out brouchure listing all the different calibers, etc. etc. .

In short, check out your local dealer for pretty pictures of bullets. :lol:
 

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nogoa said:
Also there are many variations like a .45-70. It is a .45 with a 70 grains of black powder charge.
i always thought that the "-70" was the cartridge length... at least thats how the history channel explained it.

i bet if you measured the cartridge of a 45-70 it would be 70mm long. someone test this! :)
 
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