catridges calibre...

[dr.jayakumar]

friends just wondering,how did the gun world decide on calibre?(for example)what is the reason for making an .177 instead of .175?some odd numbered catridges are manufactured through out the world like .357,.380,303,30.06,and so on.why not 350,400,310,3000?any particular reason?did the world war had any influence?kindly share your knowledge.thanks everyone.

[diskaon]

good question. May be it had something to do with the size of the projectile.

e.g. 12 bore is 1/12 of a pound of lead. hence a odd dia of 0.7 inch or so.

only people who can answer this question are long gone.

how does it matter to us anyways..

regards,
diskaon

[TwoRivers]

No, nothing to do with "gauge". Some are pre-decimal, when 1/64", or 1/128" was the smallest increment. Others are metric, such as 4.5mm = .177". Some are named for bore diameter, as per international, often ignored, convention. Others for groove diameter. Others for neither, to distinguish them from other cartridges of the same caliber. The .404, for example, is not even close to either bore or groove; .404 just must have sounded better than .410 or .422. Neither is ".32" for American cartridges of that designation. In addition, the older military calibers typically had deeper grooves than the now normal groove depth of .004", .01mm, and used bullets smaller than groove diameter. As did many of the British sporting cartridges. And could be named for any of them.
No firm rule for naming cartridges. Nowadays mostly approximations, and could be for bore, or groove.

[dr.jayakumar]

thanks friends.just inquisitive,thats all.