Why You Should Use Expander Mandrels on New Brass

[REELDOC]

Why You Should Use Expander Mandrels on New Brass « Daily Bulletin

Before you load that nice new cartridge brass for the first time, run an expander mandrel down the case necks. This will iron out dents and provide more uniform neck tension. Chose a mandrel diameter that provides appropriate neck tension.

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[Charlie]

I would think the expander plug in the sizing die would do the same thing. I just size all new cases the same as cases that have been fired.

 

[baltimoreed]

Size and expand to make them uniform just like fired brass.