Need some backup with explaining to my boss the difference between 7.62X51 and 7.62X51 NATO.  Had some bad times using non NATO 7.62 in guns made for NATO ammo.  

Please allow me to be the first to admit my ignorance.  I didn't know there was a difference.

Edited to add:  Of course the pressures may differ.

The NATO symbol on the headstamp is the only difference I'm aware of...

7.62x51 is the NATO round. The commerical .308 Winchester round is basicly the same dimentions as the 7.62x51 but has higher overall pressures. (Off the top of my head I think the 7.62 is around 50,000 vs. the .308's 68,000) This has been argued back and forth, especially when used in some of the Spanish military surplus bolt rifles. I've used both in my guns, including my Spanish FR-8 and never had any trouble.(I have heard that there is a Spanish 7.62 round used for some of these rifles loaded to lower pressures, but I have never seen it anywhere or really ever discussed, so I'm not sure it even exists) When you reload 7.62x51 military brass, you do need to load it down one full grain from the same load using commerical brass due to pressure issues according to most manuals. I think if your gun is in good working condition, you wont have any trouble.

308 Winchester vs 7.62 Nato, FWIW, "0.013" is nowhere near the difference between 223/5.56 chamber dimensions, (0.164), and for all practical puposes is NOT APPLICABLE here, no need to confuse neophites who are confused enough already about calibers....

They are close enough to be considered the same and RARELY EVER cause problems in modern firearms, IMO.

www3.sympatico.ca/shooters/7_62vs308.htm

Mike

My exp is out of the norm then, had major failure to extract problems.  Destroyed 2 sets of bolts on Miniguns with this ammo.