Neck Die Set Features Redding neck die sets for bottleneck cases contain two dies. The neck (NK) resizing die contains a decapping rod assembly with a neck expander (size button). The seating die (ST) includes bullet guide built in crimp ring and the proper seating plug. Neck Die Set Specifications Neck Resizing Die with decapping rod assembly with neck expaner Seating Die with Bullet guide crimp ring and proper seating plug 6.5 SAUM and 6.5mm GAP 4S