The I is .318, the IS is .323
Just admit it. You don't have any hands-on experience with the things you are talking about. I, on the other hand, do.
Your mixing up bullet sizes could be dangerous.
I give up. You haven’t a clue.
No. The 7.92x57IS has a bullet diameter of 8.20mm, NOT 7.92mm.
http://en.wikipedia.org/wiki/7.92x57mm_Mauser