New to reloading rifle ammo and just wanted to verify something. My question pertains to full length resizing brass with my Hornady Custom set of (2) dies. I have a Bergara HMR 6.5 CM and my son has a Ruger Precision 6.5 CM. I have measured the headspace for both rifles from our fired brass and plan to bump them back 2-3/000 from the corresponding measurements. So is it necessary to keep the fired brass from each gun separate prior to reloading? Or, since I'm full length resizing and bumping the shoulder back is that not necessary? Thanks.