In guns, particularly firearms, caliber or calibre is the approximate internal diameter of the barrel, or the diameter of the projectile it fires, usually shown in millimeters, or in hundredths or thousandths of an inch.
https://en.wikipedia.org/wiki/Caliber
Size and relative power. A .40 caliber bullet is .40 of an inch and the entire cartridge is 28.8 millimeters long. A .50 caliber (handgun) bullet is .50 of an inch and the ent … ire cartridge is 40.99 millimeters long.
http://www.answers.com/Q/What_is_the_difference_between_calibers
When expressed in inches in writing or print, it is shown in terms of a decimal fraction: .45 caliber, for example. When the barrel diameter is given in inches, the abbreviation cal can be used. For example, a small-bore rifle with a diameter of 0.22 inches can be called a .22 or a .22 cal; however, the decimal point is generally dropped when spoken, making it a twenty-two caliber or a two-two caliber rifle.
https://en.wikipedia.org/wiki/Caliber
A .25 becomes 6.35mm. A 9mm becomes a .354. 2) Survivalblog has a good table of common converstions between caliber and mm here: http://survivalblog.com/2011/06/understanding-metric-and-inch.html. 3) This site: http://www.ballisticsbytheinch.com/index.html shows the effect of barrel length on common calibers.
http://www.thesurvivalpodcast.com/episode-855-understanding-caliber-millimeter-gauges-and-balistics
Difference Between 9mm and .40 Caliber. • Categorized under Objects | Difference Between 9mm and .40 Caliber. 9mm vs .40 Caliber. If you want to start owning and shooting guns, you’ve probably wondered on the type of gun to start with. Two common options are 9mm and 0.40 calibers. The main difference between 9mm and 0.40 calibers is the size of the bullet.
http://www.differencebetween.net/object/difference-between-9mm-and-40-caliber/
Sometimes when you are talking about a firearms subject I am fine then you start saying something like the 38 special is 35 caliber and I just don’t get it. Or that a 40 S&W is equivalent to a 10mm in a carbine.
http://www.thesurvivalpodcast.com/episode-855-understanding-caliber-millimeter-gauges-and-balistics
For example, a firearm might be described as a '.30 caliber rifle', which could be any of a wide range of cartridges using a roughly .30-in projectile; or a .22 rimfire, referring to any rimfire cartridge using a .22-cal projectile.
https://en.wikipedia.org/wiki/Caliber
Caliber refers to the size of the bullet in the cartridge, or the size of bullet the gun is designed to fire. Magnum refers to a cartridge with a higher level of pressure/powd … er than another one similar to it. For example: a .44 magnum has a longer casing and more powder than a .44 special.
http://www.answers.com/Q/What_is_the_difference_between_calibers
The 30-06 is the Father and Grandfather of Many Rounds. When I stated I wanted to do some more shows on firearms topics I was flooded with emails by new shooters that all basically said some version of this…. “Jack can you do a very basics style show that explains what all these calibers and rounds mean.
http://www.thesurvivalpodcast.com/episode-855-understanding-caliber-millimeter-gauges-and-balistics
Caliber is a measurement of the diameter of the projectile or case of a cartridge for a firearm. 1.00 caliber is equal to one inch, .50 caliber is equal to one half inch. Firearms are made to a wide variety of calibers, from .17 through .50 mostly.
http://www.answers.com/Q/What_is_the_difference_between_calibers
difference between calibers
1.00 caliber is equal to one inch and .50 caliber is equal to one half inch.