alright i don't understand something in the directions. it says "the decap rod assembly comes w/ an expander ball/ decap pin holder installed to allow for the proper preparation of a new lot of brass. the decap pin holder found in the accessory bag must replace the expander ball for proper use with the neck bushings." i thought that the die can only be used w/ the bushings sold separately? so when would i need to use the expander ball, if i can't use it w/ a bushing installed? am i suppose to use the expander ball on all new brass? and use the decap pin holder when i am resizing used brass?

If the RCBS is like Redding bushing dies, you can size with or without the expander. New brass might have oval shaped mouth/necks. The expander would make them round again. After fire forming the brass,the expander is not needed if using the correct bushing.

If you are not using a bushing die use the expander for both old and new. My RCBS FL dies don't have a bushing option.