There are very slight differences in real life between the two cartridges (.308 Winchester develops roughly 4% more pressure than 7.62x51mm NATO), which are too small to be considered important; [https://en.wikipedia.org/wiki/Sporting_Arms_and_Ammunition_Manufacturers%27_Institute SAAMI] considers it safe to interchange .308 Winchester and 7.62x51mm NATO. As far as the game is concerned, the cartridges are identical in all but name, and it is considered acceptable to use either designation to refer to the same cartridge.
7.62x51mm is typically pronounced ''seven point six two by fifty-one millimeters''. It is also acceptable to pronounce 7.62 ''seven point six two''.<br/>
.308 Winchester is typically pronounced ''three oh eight Winchester'', though ''two twenty-three Remington'' is also acceptable.