I'm forming 6.5 Remington Mag from 300 Winchester mag. Steps are: 1st step run into 350 Rem Mag trim die, 2nd step run into 6.5 Rem Mag trim die, 3rd step full length size with de-capping pin removed. No annealing required. Necks need turning/reaming. If I ream after 3rd step, neck tension is inadequate. I could outside turn after expanding neck, but to what size? Is this trial and error, or do you use the outside neck dimension as listed for the 6.5 Rem Mag after expanding neck?