Up to this point, I have been using new WBY/NORMA brass with my 257 WBY MAG. I have 100 pcs of each brand. So, last night was my first attempt at sizing some cases. Using a Redding FL die I found the die was sizing like a bushing die. In other words, it was sizing well short of the neck/shoulder junction. It's just like a bushing die was being used. I then used a mandrel to finish up the sizing. While running the mandrel through the neck it was pretty smooth most of the way. Then it would sort of hang up. After some back-alley measuring, I determined the mandrel was hanging up right where the unsized portion of the neck started. So I guess I have a bit of a donut on the inside of the neck? What can I do to get the FL die to size the entire neck?