300 Blk Sizing Die Shootout - Part 3
This video details a DIY modification to a Lee 300 Blackout sizing die's expander ball to address inconsistent neck tension. The instructor demonstrates a process of sanding down the 0.307" expander ball to a smaller diameter (0.306" or 0.305") using various grits of sandpaper and finishing with polishing materials. The goal is to achieve tighter neck tension, comparable to Forester and RCBS dies, to prevent bullet setback during chambering.












