Thanks for your argumentate reply Sir!
I presume, from fired case neck, that my neck chamber are about.294"/.2945".
My standard loaded round measure a the neck .290"
I plan to turning the necks at .0125", only a skinny turning and only for make a sort of consistency on the neck thikness.
So with skinny turned neck a loaded ammo with Scenar 139gn measure about .289" for a total chamber clearance of .0055" (.00275" per neck chamber side).
.0055" or .006" of clearance are a good clearance or not?
Now the Lapua brass case for 6,5x47 Lapua have a neck tickness about .01325" on average measure now on some new unfired cases.
The neck thikness may vary, on the same case, from .01255" to.0137", very inaccurate for the current price (165€ or more for 100pcs) on my "socialist" country
Thanks for all the replyes!