Re: Do you have to size new brass?
Actually, a better choice than the expander ball is the Lee Collet Neck Sizer. It presses the neck against the decapping rod so it is exactly aligned and uniformly round.
The neck sizing ball can actually cause the neck to be slightly misaligned.
After collet neck sizing my new brass, I then trim, chamfer, and do all the flash hole preparations. After firing, I anneal to ensure all the brass are on the same page ductility wise.