Considering the fact that a rifle whose bolt face aligns dead center on the chamber when the bolt's closed and the hole in the bolt face is dead center on the bolt face, the external extractor will push the case off center in the chamber and on the bolt face anyway. This automatically puts well centered primer pockets on case heads a bit off center relative to the chamber.
But the direction and amount's very repeatable from shot to shot. Good accuracy's guaranteed. . .if all else is good, too.
And if the pressure ring on the case is bulged out quite a bit at one point and that is at the same point were the extractor presses the case off center, that may well end up centering the primer on the firing pin/bolt-face-hole.
Stranger things have happened. But the little details of how all this stuff works has been facinating to me.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master
Last edited by Bart B.; July 2, 2013 at 09:42 AM.