I just bought new .308 brass from Winchester for the first time since my spent casing collection ran out. I measured headspace and found many casings at 1.622. This seems excessively under headspaced to me given minimum case headspace is 1.627. My fire formed cases indicate my Rem 700 has a chamber headspace of 1.635, so this is a .013 difference in headspace. It seems like this is too much given the difference between a Go - Field gauge for that chambering is a range of .008 for safe tolerances. I'm assuming I'm missing something here?