Sunray
Member
"...My head hurts now..." That'd be the brain damaged caused by trying to figure out why cartridges are named what they are. Goes away when you stop thinking about it.
Most commercial cartridges are named for marketing reasons. Modern military cartridges are, usually, named to avoid confusion with another country's or previously issued, military cartridges.
As mentioned, mathematically, 7.62mm converts to .30 inches, but .308" doesn't convert to 7.62mm. .308" converts to 7.82mm. 7.62 is the bore diameter across the lands. .308" is the nominal diameter across the grooves.
Since NATO came along, military cartridge designations have been metric.
Most commercial cartridges are named for marketing reasons. Modern military cartridges are, usually, named to avoid confusion with another country's or previously issued, military cartridges.
As mentioned, mathematically, 7.62mm converts to .30 inches, but .308" doesn't convert to 7.62mm. .308" converts to 7.82mm. 7.62 is the bore diameter across the lands. .308" is the nominal diameter across the grooves.
Since NATO came along, military cartridge designations have been metric.
(e.g., the 7x57mm Mauser used in the Spanish-American War.)
