Hornady Quick Change Powder Die Powder Through Expanders are for use in conjunction with the Hornady Case Activated Powder Drop and Quick Change Powder Die. These powder through expanders have been redesigned to work with both lead cast bullets and copper plated bullets and allow reloaders to charge cases while expanding the case mouth. (Hornady suggests that the station directly after the station where the Quick Change Powder Die is installed that reloaders install the Powder Cop Die (sold separately) to ensure that cases received the proper powder charge).Notes:For use with the Quick Change Powder Die, and used in conjunction with the case activated powder dropEliminates the need for a separate case mouth expander dieThe expander is inserted into the powder die and then the case activated powder drop sits on top of that die with the powder measure on the topExpanders are designed to expand to a certain case mouth diameter.