ired case diameters are smaller than chamber diameters
but they are concentric , yes ? no bent necks ?
consensus has it that Lapua brass has a springback of .0005"-.001 after sizing or expanding. With tens of thousands of psi inside that case for a few milliseconds that case will conform exactly to the chamber. That case is going into the sizing die concentric it's when the neck is being pulled or pushed while the shoulder is not supported that pulls it off axis. Only reason I can see is the expander button. I tossed all of mine and the concentricity problems went bye bye. I use the bushing style dies so I can play with neck tension and neck turning, otherwise any decent die from Lee on up will work