Also if you can get a Lee Collet neck sizing die and remove the expander ball from you full length/neck only sizing die. The expander ball stretches the case way more than the firings do. I have miked numerous calibres before and after the expander ball has been through them. They all stretch but the shallower the neck angle the greater the grow. Yes I have the hell lubed out of the expander ball and inside the neck. The better the lubing the less stretch but they still stretch.

I suspect the elliptical ball like the Hornady one will produce less case neck stretching but have not experimented to find out.