What round does a rfi 7.62mm 2a1 take?

The 7. 62mm 2A/2A1 is a 7. 62mm NATO, also called 7. 62Ã?51 caliber. Although the 7. 62mm NATO and commercial . 308 Winchester ammunition are physically interchangeable, these weapons were not designed for use with commercial . 308 ammo.