dellet
Gold $$ Contributor
I would try a different lube, and coat the inside of the neck, instead of or in addition to to the mandrel.
I use Redding’s dry lube which is basically graphite and their application method. They mix the graphite in with small balls, to apply by dipping the case neck into the graphite. It would be easy to duplicate.
I have found this to work very well, expanding a caliber at a time.
I also wonder if what you are seeing might be more visual than actual scratches. Something that was already there being polished.
I use Redding’s dry lube which is basically graphite and their application method. They mix the graphite in with small balls, to apply by dipping the case neck into the graphite. It would be easy to duplicate.
I have found this to work very well, expanding a caliber at a time.
I also wonder if what you are seeing might be more visual than actual scratches. Something that was already there being polished.