10-07-2022, 03:02 AM
Comparing case lengths from the base to the datum line between unfired cases & fired cases will tell you how far you need to set back the shoulder when resizing your cases. The SAAMI spec for that length is 1.220"-.007". Can't affirm the Hornady comparator is exactly .350" in diameter but it will be real close. They're mass produced so there could be some differences in individual comparators. They're close enough to give you a good idea what your case lengths are at the datum line.
From an Odin 6.5 Grendel barrel, my my fired cases came out 1.223" - base to datum line. At first I set those cases back to 1.221". That was enough set back to allow for proper feeding into that barrel's chamber. But then I decided to change the barrel to a Wilson Combat barrel, so, I went back & resized them again to a 1.220" headspace dimension before I'd shoot them in the WC barrel. I haven't shot those cases yet. Before I do I still have a boat-load of factory ammo I wanna shoot first.
From an Odin 6.5 Grendel barrel, my my fired cases came out 1.223" - base to datum line. At first I set those cases back to 1.221". That was enough set back to allow for proper feeding into that barrel's chamber. But then I decided to change the barrel to a Wilson Combat barrel, so, I went back & resized them again to a 1.220" headspace dimension before I'd shoot them in the WC barrel. I haven't shot those cases yet. Before I do I still have a boat-load of factory ammo I wanna shoot first.
I refuse to be victimized by notions of virtuous behavior.