Proper bullet diameter is essential for cast bullet accuracy.
If you cast your own bullets, then this tool allows the reloader to bring the bullet down to size and apply lubrication. Lyman sizing dies have spacing for easier bullet lubrication, even with today’s hard lubricants. Lyman sizing dies also feature a tapered mouth and hardened interior insuring alignment for perfect cylindrical shape. Interior dimensions correspond to suggested diameters for all popular rifle and pistol calibers.(These are interchangeable with RCBS)