I have been reloading for many years and I think I know the answer to this question, but thought I would ask anyway. I generally use Lapua brass for my reloading needs, along with Reading Type S Full Length resizing dies. I have a Remington SPS Tactical .308 that I have been reloading for recently. I have been noticing that the bolt handle has been getting harder to lift on some rounds fired at the range. Investigating, I also found that while there is little variation in my overall velocities of shots on my chronograph, there is a correlation to the cartridges which are making the bolt stick and fliers. Using a Stoneypoint/Hornady shoulder gauge I am finding as much as .005-.006 differential in the overall measurement of the brass at the shoulder to the case head. The brass has been used with another .308 in the past and has differential times fired: i.e. one piece may have been reloaded twice and one six times.
My guess as to the why this is happening is brass work hardening. As the number of firings has increased, the ability of the case to spring back and/or hold the dimension in the sizing die is reduced due to the work hardening of the case. The cure should be annealing the brass, correct? At t his point I may also simply retire/recycle the used brass and go to a fresh consistent lot. Let me know your thoughts.
Thanks
Elk
