Whats the difference between 7.62x51 and .308? I Found out that century chambered the MAS in .308 and not the nato standard 7.62x51, but they are pretty much the same cartridge, only when a 7.62x51 was chambered at the range, it couldnt be ejected by hand, and when a .308 was chambered it would eject by hand. Can a gunsmith modify this, id love to use cheaper 7.62x51.