I recently purchased some 308 Lapua brass. I necked it down to 243 win. I am now turning the necks. I have a Lyman case trimmer with a neck turning adapter. When I set the brass on the pilot and turn the handle the brass spins eliptically. I think the set screw on the pilot forces the pilot off center. I have turned some cases but they do not appear to be centered. When I check them on my RCBS case gage, they wobble. They are out from .006 to .010. Any suggestions?