I just picked up an AR on trade yesterday and have a basic (probably stupid) ammo question. It is marked for 5.56mm. My question is are 5.56mm & .223 one in the same? Or do I need to use only 5.56mm ammo?
other way around with the 308/7.62 Nato. Commercial 308 is rated to a higher pressure than Military 7.62x51. So you can shoot 7.62x51 Nato in a 308 Winchester chamber, but you should not shoot commerical 308 Winchester in a rifle chambered for 7.62x51 Nato.