OK, I'm showing that 7.62mm exactly equals .3000". However, my understanding is that .30 rifle cartridges have a bullet diameter of .308, which is 7.82mm, NOT 7.62. So why then are the 7.62 NATO round, and other .30 rounds labeled 7.62, called what they are, rather than "7.82 x ____"? Are they not .308? Seems very silly to get so specific as to go to the hundreths of mm, yet be off by 2/10ths, or 20/100ths, of a mm in the designation. Is my math just incorrect?