I shot my .308 today, I shot Lake City 7.62x51mm M118, as I always do. After I shot I looked at my casings and all three looked like a "baseball diamond" on the neck. I inspected the chamber and it looked fine. Any idea as to what would have caused this? The rifle is a Ruger M77 MKII with a V/T barrel, it shoots really tight groups at 100 with this ammo. I have only had damage on one other casing before today, but it was along time ago and I have shot alot since then. Another question is can this be reloaded?