http://www.saami.org/PubResources/CC...Winchester.pdf
Jersurf101,
“I think the problem is that I am not getting the shoulders set back far enough. I am using a Lee .308 win die on a Lee challenger kit. Is it possible I need a new sizing die? The sizing die I have cannot go any lower as it is touching the shell holder on the ram. The micrometer says that the shoulders on the LC read 1.72" while the Nosler and Winchester that were fired in the gun measure 1.715" if that helps. Is this a known problem with a Lee sizing die?”
1.715” and 1.720” ? I am the fan of standards, and transfers and verifying. That puts me in a class all by myself. To use a gage like the Hornady comparator there must be a way to zero/index the tool, I know, a comparator is used to compare, problem comparators are referred to as head space gages, the head space gage is a standard. Back to the comparator, the comparator compares before and again after. that would be before firing and again after firing, problem, most measure the case after firing and after sizing.
The measurements from the datum to the head of the case as in 1.715” and 1.720 are no where to be found listed in SAAMIs chart for the 308W. The maximum chamber length from the datum to the bolt face is 1.640”, the minimum is 1.630”, SAMMI list the case length from the datum to the case head as 1.634 with a min. of -.007”.
The difference between 1.720” and 1.640” would lead me to believe you are using the incorrect datum, I make datums, I collect datums and on occasion I purchase datums. when I use a datum the plaine is zero.
F. Guffey