Dave Wilson, you mentioned playing with the sizing die so headspace would be only 1 or 2 thousandths. As there's only 3 thousandths difference between the go (.220-inch) and no-go (.223-inch) H&H headspace gages for this cartride which headspaces on the belt, how do you change the belt's position relative to the case head? If Freak's rifle is properly headspaced it already has proper headspace someplace between .220 and .223 inch which means your 2 thousandths max headspace requirement is probably already met.
If you mean to size fired cases such that their shoulder is repositioned so the case head to shoulder datum is no more than 2 thousandths inch less than bolt face to chamber shoulder datum, I understand. Depending on the case belt position relative to the chamber belt shoulder, the case may stop upon firing pin impact before its shoulder touches the chamber shoulder. This is an "iffy" situation and depends on several dimensions.
The above aside, I've always got best accuracy from H&H belted cases when they're new and unfired. If I full-length size fired cases back to original factory dimensions (including sizing the body all the way to the belt with a special body-sizing die) then they equal the accuracy of new cases. Traditional full-length sizing, neck-only or partial-neck sizing has always resulted in worse accuracy.
