I have been using an RCBS Comp. seating die and have been getting between .005 and .008 runout. i tried the standard RCBS seater and still have runout issues. After taking apart both dies and inspecting the seating stems it looks like they were not designed to fit the A-Max bullet profile. The brass is neck sized using a Lee collet die and has zero runout after sizing so i am pretty confident it is not a brass issue. So my question is which brand of seating die would be best for this bullet profile and give me better concentricity?