The Zip Spindle design on all full length size dies positively locks to eliminate slippage. A series of light threads cut on both the spindle and spindle collet allows you to make incremental adjustments by turning the spindle or you can easily "zip it" up or down for larger movements.
The Hornady Sure-Loc lock rings clamp around the entire die applying constant pressure across the threads to hold the ring in place. The locking screw tightens the ring without ever coming into contact with the threads, eliminating possible damage from pliers.
Superior to "ball expanders," this Hornady exclusive provides extremely smooth neck sizing and significantly reduces friction and case neck stretch. Internal threading prevents it from pulling loose and the elliptical expander also eliminates the need for a separate expander die for necking-up to the next caliber.