Thread: Expander mandrel use ? Is it worth it ?

I have a loaded case giving me neck OD of 0.336. If I resize using 0.334 or 0.333 bushing then put case through a 0.307 expander mandrel am I sizing the neck down to give it a 2/3 thou worth of neck tension then expanding it to give it a 1thou case neck tension ?

Reloading 300NM with 30cal 230g atips

Forgive my naivety, all new to me!

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