04-11-2021, 02:13 AM
When I started on my 400 pieces, I bumped 5 back to SAAMI minimum of 1.183 base to B comparator line. Used them for my initial function check and then was able to use the fired measurement for sizing the rest. If you size all of them down to SAAMI minimum, you would possibly be subjecting your brass to unneeded stretch, but any virgin ARC brass would also be at SAAMI minimum (or below) - as would any brass in factory ammo. In my case, my Lilja chamber is 1.188 and I bump them to 1.185, so if I had bumped them all to 1.183, it wouldn't have had an impact on my brass life.
While you ponder that, fire up the trimmer! Your going to need to take 0.03" off and take them down to 1.480" OAL, and you should do this before you bump down since the longer Grendel brass could hit the top of your die. It did with my Hornady die and I lost a couple to dimples on the shoulder. The trimming is the vast majority of the work. You could/should do your chamfering/deburring too. After that it's just a quick lube on the shoulder and inside/outside of the neck and through the sizer.
While you ponder that, fire up the trimmer! Your going to need to take 0.03" off and take them down to 1.480" OAL, and you should do this before you bump down since the longer Grendel brass could hit the top of your die. It did with my Hornady die and I lost a couple to dimples on the shoulder. The trimming is the vast majority of the work. You could/should do your chamfering/deburring too. After that it's just a quick lube on the shoulder and inside/outside of the neck and through the sizer.