I got a buddy that is in the Natl Guard here in WA. We have been talking lately about military rifles and the like that he has experience with. The big thing is he doesn't know much about the calibers, in the standard caliber measurement, and millimeters for that matter. He informed me that the 7.62 that the M249B machine gun shoots, can be fired out of an AK-47. He showed me his field manual and I noticed it said NATO 7.62 for said machine gun (I am assuming this is not the SAW(M240?) that shoots the 5.56 that the standard issue M16/M4 and variants shoot the military use). As I have come to learn is the 7.62 NATO is nearly the same measurements as a .308 Winchester. I have heard 7.62 NATO guns shouldn't be advised shoot the .308 Win, but a 7.62 NATO can be shot out of a .308 Win gun. I would like to confirm this in most cases that is true. So, the question is, can the 7.62 round that is shot out of this M249B machine gun, actually be shot out of an AK-47? He informed me he was told that in basic, but I don't know if he is getting things mixed up or not. As I see the 7.62x39 and .308 Win side by side, the .308 is considerably taller, so thats where my doubts lie in the fact that it can't be done. I know the size of the projectiles in both types of ammo, are roughly .30 cal. and feasibly the same round might be able to shot out the barrel, but the .308 Win won't fit in an AK mag, and would have to be fed round by round if it were to fire from an AK. I am quite confident I am right on this one. I'm not so good with the military jargon, so please any corrections if I misnamed any of the guns in questions.