newsteadvic wrote:oldnews wrote:Can someone explain this to me.
Something like the .22 or .223 use a .224 calibre bullet. The bullet (according the names and numbers) is larger than the bore of the rifle.
Then you have .308 which uses a .30 calibre bullet. The bullet is smaller this time than numbers would suggest.
However the .308 has a .308 groove diameter, a .30 bore diameter so it does make good sense. This is a nice picture demonstrating lands and groove and bore for the Russian 7.62x54R (.30 bore but .314 groove diameter, takes a .311 bullet - same as .303 british):
However I do agree there are some that make no sense - 38special is actually the same as 357
Thats almost on the money... but the 7.62x54R has a 7.92mm proj (.312inch) like the 303Brit, but the land /groove dimensions are 7.62/7.92 (0.300/0.312)...
Cartridge names can be taken as arbitrary 'names' and as a guide really to the bullet or bore size....
The 222Rem, 223Rem, 220Swift, 5.7x28, 5.6x57, 224 Weatherby Mag all use 224 proj....
308Win, 30-06Spring, 300Win Mag and others... all have a 0.308groove diameter, and use a 0.309Proj....yup...
44 Remington Magnum has a 0.429 groove and a 0.432 proj.... 44 Just sounds more 'manly'
Some cartridges use bullets undersized to the groove(303Brit) which partially engrave the rifling, some use groove sized bullets (243Win) which fully engrave, while most others use oversized projectiles (223Rem, 308Win almost everything else) which swage down and fully engrave the rifling.....
There are different systems, Euro, US, arbitrary, words - magnum, nitro, express, short, long, ultra, super, special...then the numerals.