what calibre mean

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What does "Calibre" mean

Well, apart from the small detail of Americans spelling it differently to everyone else, "calibre" is simply the diameter of the projectile. Like, a 30 calibre projectile has a diameter of .308 inches. (Yes, I know , "inches" is an ancient measurement, but shooters and rifle makers are an ancient mob). This designation of a ".308" is also called a 7.62 (in mm which most of the rest of the world understands!).
Now, a "44 calibre" bullet has a dia of .430 inch.
Then again a "45 calibre" projectile can have a diameter of anything from .450 inch to .452 inch.
Simple eh?
Next you should understand the measurement of "gauge" in smooth bore shotguns; a "12 gauge" shotgun has a bore the diameter of lead ball which would take 12 to make a pound. (weight that is, not pound sterling, the currency!)
Similarly a "20 gauge" shotgun has a bore the diameter of which would take 20 lead balls to make a pound.
This measurement is similar to the way wire diameter is measured; the number if strands of wire which would fit in a circle of an inch diameter is the "gauge"...so 12 gauge fencing wire has a diameter such that 12 strands could be bundled into a one inch circle.
Welcome to the wierd and wonderful world of shooting. Enjoy the sport, the culture and the history.
 
Take your pick:

From the American National Rifle Association: [ http://www.nraila.org/Issues/FireArmsGlossary/ ]:
The nominal diameter of a projectile of a rifled firearm or the diameter between lands in a rifled barrel. In this country (United States), usually expressed in hundreds of an inch; in Great Britain in thousandths; in Europe and elsewhere in millimeters.
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From an Australian site: [ http://www.firearmsmuseum.org.au/Survey/Glossary/Glos-ind-fra.htm ]
Distance across the bore measured from land to opposite land. In the U.S. and England this measurement is usually given in .00 or .000 of an inch. In Europe and Asia the measurement is generally expressed in millimetres.
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From [ http://www.building-tux.com/dsmjd/tech/glossary.htm ]:
The internal diameter of a gun's barrel. This can be measured either in English units or in metric. The measurement can be taken in a rifled arm either land to land or groove to groove. E.g., in most .30-caliber rifles, the diameter of the bore land to land is .300 inches, while groove to groove it is .308 inches.
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Cual Libra?

What Poundage?

As in, "what poundage is that there gun?", response, "Why, thats a four pounder!"

This became, by expression, over the years, "Calibre"
 
"Calibre" is a guarenteed way to cause a flamer-war.

If you ever begin any post with the words "What calibre for..." then that thread will run for thousands of pages and millions of posts; not one of which will actualy say anything new past the third post or so.
 
How did they determine what caliber to call things in the pre-civil war era?
a .44 cap and ball revolver shoots a ball between .452 and .457 - what we would consider a .45 caliber. Our modern .44 caliber is .429 I think and a .36 cap and ball is considerably larger than what we call a .38 today but a .45 colt shoots a .452! Really seems confusing.
 
Cual Libra?

What Poundage?

As in, "what poundage is that there gun?", response, "Why, thats a four pounder!"

This became, by expression, over the years, "Calibre"
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Do you have a reference for this? Every reference I've seen shows it was derived from a Greek or Arabic word for a shoemaker's last that passed through Italian and French on the way.

http://www.etymonline.com/index.php?term=caliber
caliber
1567, from M.Fr. calibre, via Sp. or It., ult. from Arabic qalib "a mold, last," perhaps from Gk. kalopodion "a shoemaker's last," lit. "little wooden foot," from kalon "wood" + podos gen. of pous "foot" (see foot). Arabic also used the word in the sense "mold for casting bullets," which is the original lit. meaning in Eng., though the earliest cited sense is the fig. one of "social standing, quality, rank." Calibrate is attested from 1864.
 
Too bd most ppl use the word caliber as a cover all word for cartridge and chambering. Ppl will ask "what caliber should I get" and the responders will give cartridges as answers. :banghead: .30-06 is NOT a caliber it's a cartridge. :cuss:
 
The technical explanations above are right, as far as they go. But then the sales department gets involved. Consider that .218 Bee, .219 Zipper, .220 Swift, .221 Fireball, .222 Remington, .223 Remington, .224 Weatherby, and .225 Winchester are ALL the SAME caliber. Their barrels are the same diameter, .218" across the lands (Which would be the caliber designation if everybody followed the dictionary definition.), .224" from groove to groove. The cartridges and chambers differ, often by a lot, don't get the idea that I am talking about interchangeable ammunition; but the hole down the barrel is the same.

Lubek Tech, the transition from cap & ball to cartridge was not simple, even in nomenclature. Colt took a barrel blank and drilled a .36" hole down it. Then they rifled it with deep grooves to spin up the ball. Then they reamed the cylinder to be loaded with balls at a press fit. It takes about a .375" ball to seal the chamber mouth and fill the grooves. When they started making cartridge guns, they started calling them by the bullet diameter, .38 to two decimal places. Later cartridge design called for inside lubricated bullets which were of smaller diameter to fit the bearing surface inside the brass instead of outside (Like a .22 LR still does.) They kept the same cartridge and chamber diameter but made bullets and barrels smaller. New products kept coming out and getting new names. Which is why a .38 Special and a .357 Magnum use the same bullet and barrel diameter.
 
I see the OP hasn't responded yet ... I think you thouroughly confused him. Much the same as you completely confused me and I'm American!
 
In firearms usage, caliber (or calibre) typically means bore diameter, but as brickeyee pointed out, it also sometimes notes the length of the pipe, e.g., the USS Missouri (BB-63) main rifles were 16" 50 cal., which means they were 50 x 16" long = 800" or 66.67' barrels... which could throw 2,700 lb armor piercing shells some 24 miles. Wonder just how accurate those bad boys were? :eek:
 
I think that the real meaning of the word , was given to us by Doctor Evil, and that it's correct usage is, as a Homnym. Such as, ' both the caliber of the bullet of these weapons, and ... the quality of .. the character of... these girls.."
 
CNYCacher No 30-06 springfield is a Cartridge, a rifle so chambered is labeled as such. The distinction gets teeth when you consider that you can "chamber" a .270 Winchester in a rifle reamed for a 30-06!

LubeckTech: The reason that the .44 cartridges actually fire a .429-.430" projectile is actually well known. Prior to S&W's contract with the Russian Government for handguns, their .44 cartridges were all loaded with heeled outside lubricated lead projectiles. The arrangement was similar to present day .22LR cartridges. When the Russian govenment insisted that S&W develop a special cartridge for them, they included a demand that the bullet be inside lubricated (like all current lead projectiled cartridges). S&W designed the .44 Russian by simply taking the .44 American brass (as it was known) lengthening it slightly, and putting a smaller diameter non-heeled bullet inside the case mouth. This made it neccessary to reduce the barrel diameter somewhat but the result was a superior cartridge that didn't pick up all sorts of dirt and grime in it's lubricated bullets, thereby reducing wear on the barrel.

As for why the Black powder handguns had such odd barrel diameters, I'd wager that a .44" projectile was the true diameter, however the bore needed room to accomodate fouling as well as a patch so that the handgun would be easier to reload when fouled. Further, since many of those barrels were made through the old hammer forging methods, precision tolerences were hard to hold.
 
Further, since many of those barrels were made through the old hammer forging methods, precision tolerances were hard to hold.

Probably the reason so many people preferred muzzle loaders for years to come.
You knew you had the right size bullet when the gun went boom.
 
It is also the length of the barrel in bore diameters for larger guns.
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Navel weirdos.:D

I always wondered why this big old honkin brass ashtray made from a cut down brass navel case Ive got on my desk says 3 inch, 50 caliber:scrutiny:

A gun with a 3 inch bore, and a 150 inch long barrel.:eek:
 
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