Redding Reloading .324 Heat-Treated Steel Neck Sizing Bushing. Because of variances in thickness for the neck brass the standard die sizes the neck under the preferred diameter. To get the proper tension on the bullet an expander ball is pulled. In addition this bushing is self-centering and changeable which makes it possible to set the amount of tension on a bullet with precision. As a result there is less work on the brass helping prolong life while increasing accuracy. Package Contents: Redding Reloading Heat-Treated Steel Neck Sizing Bushing Redding Reloading 73324: .324 Heat-Treated Steel Neck Sizing Bushing