Re: Once Fired Brass question
"always" is a pretty encompassing word. I would be inclined to say "not always". [img]/ubbthreads/images/graemlins/smile.gif[/img]
Typically, factory ammo or factory new brass is quite a bit undersized so that it will fit in any SAAMI chamber.
If comparing factory ammo or new brass with once fired, neck sized or properly full-length sized cases you may see a measurable difference. However, in an average factory hunting rifle, with groups running 1.5"moa, the accuracy may not be good enough to see any difference at all.
I have shot (previously fired)neck sized cases and full-length sized cases in the same rifle without seeing a difference in group size. If cases are properly full-length resized they will only be reduced in size enough to allow the bolt to close easily and no farther.
Another advantage to minimally resizing cases is the reduction in work stressing cases, thus extending case life. Extreme over sizing will cause headspace problems and case failures. [img]/ubbthreads/images/graemlins/mad.gif[/img]