I just start check case neck runout and measuring neck thickness. So I had a few questions. If it makes a difference I am working with new RWS brass that has been ran through a neck sizer and will be for a 300 win mag. First, what is acceptable runout on the case neck, and is this number also good for when you check the runout on the bullet? I have some that are .001 and some that are .006. With the cases that have more runout, I measured the wall thickness and there was a difference in thickness. This means that the cases that have a larger difference in wall thickness need to be neck turn??????? Second, what is the correct way to determine how much material to remove from the neck when you are neckturning. Once again not sure if this means anything but my rifle does not have a factory barrel. So, am I looking for a consistent thickness in my brass from the thinnest measurement off of the case wall at the neck. Or, am I looking for a consistent thickness in my brass that is just a touch smaller than neck in the chamber? Third question. Does the brass need to be fire formed before any of these measurements means anything, or is vergin brass the best to start with? I really hope what I wrote makes since, and thanks for the help.