The best course of action is to not use any expander ball in a sizing die at all. Forster hasnt figured out any magic there- it still plows an expander back thru a case. They just put it in a different place to make you think it must work better (but it doesnt)
I do not live in fear of the dies expander and after testing seven different .223 dies the Forster full length dies produced the least neck runout.
And Redding put a expander in their bushing dies for a reason.
Tech Line & Tips (FAQs)
Bushing Selection
https://www.redding-reloading.com/tech-line-a-tips-faqs/140-bushing-selection
If the neck wall thickness varies more than 0.002", it may be necessary to use a bushing a couple of thousandths smaller than your calculations indicate, and then use a size button in the die to determine the final inside neck diameter.
Below I installed a Forster expander and spindle assembly on my Redding non-bushing full length die. And it greatly reduced the amount of neck runout vs the Redding expander. The reason for this is the Forster expander enters the case neck when the case neck is held and centered in the neck of the die. Meaning the Forster expander does not pull the case neck off center like other dies.

Last edited: