I just happened to read an article on this topic tonight. They are very, very close in pressure (statistically the same). The difference in some of the pressure postings was that the military changed how they measured the pressure. That caused the discrepancy.
The subtle difference in the two rounds is that the nato case is slightly beefier to compensate for more slop in the chamber. This is so the gun can operate in dirty conditions out in the battlefield.
You can use either in this gun. That's why they are both listed.
Here's a link to an article:
http://www.thefiringline.com/forums/showthread.php?t=326877&highlight=.308+vs+7.62
The subtle difference in the two rounds is that the nato case is slightly beefier to compensate for more slop in the chamber. This is so the gun can operate in dirty conditions out in the battlefield.
You can use either in this gun. That's why they are both listed.
Here's a link to an article:
http://www.thefiringline.com/forums/showthread.php?t=326877&highlight=.308+vs+7.62