RE: Remington Brass
Well, if you roll your loaded round, you might see your bullet wobble. .003" or less at the Ogive is fine, but it gets harry after that. If your brass thickness isn't uniform at the neck, you will get runout.
Usually if you run your brass thru the FL die without the expander and test the neck runout, there will be none. If there is any, you better question your die or shellholder. And then you can run your expander thru from the top (this usually causes less runout than pulling it thru), and test again. Pulling your expander ball thru usually causes the runout to be worse. Thats the reason you need to lube the inside necks well. Here is where the collet die from lee shines.