You missunderstand mate.
When you put a sharp VLD chamfer on a case, it gets easilly mangled during the STM tumbling process. You then need to re/trim or de-burr. As I dont really need a VLD chamfer I just re-set the blades on my cutter to tidy up and de-burr with a trim, rather than putting a sharp old bashable edge on it.
IF you dont tidy the case mouth up, the neck can remove copper from the bullet via the burred edges.
Sorted now as it goes
I'm a maggot in another life you know