There are many thoughts, theories and ideas what causes the dreaded dounts. What befuddles me, you can have twenty sticks of brass, even our beloved Lapua using the same exact lot number of brass, sizing methods and tools some of the will develop donuts and others don't.

If donuts form I'll expand the necks all the way into and past the shoulder to push the thicker brass to the outside then turn it off just barely nicking the shoulder. That's where the little buggers like to hide. Don't go too deep otherwise you can run the risk of neck separations.



Bill