I am reloading .308 winchester. I have a pair of digital calipers for which i am scrutinizing size differentials in brass. I am using a set of lee deluxe dies and am only neck sizing at the moment. I am finding neck sizes are different after resizing. They are only fractions of an inch different, but different none the less.The length of the brass differs also. It is in safe reloading parameters,according to lee manual, but still fractions out. Will these size differences matter, or should i only use brass with the same neck and length size. Regards, Ed.