My dad just started reloading .308, he has always done pistol ammo for the most part. Well, the cases needed trimmed as their OAL was too long. After trimming it made a grooved looking cut and when you look down inside the case, the trimmed edge appears to have four marks on the edge located at 12, 3, 6, and 9. Is he pushing a little too hard when he trims? thanks guys.