Brass problem in neck area.
Hi members, has anyone ever had this problem. Started with new unfired Federal 300rum brass, full length sized without expander ball. Next I expanded with a K&M expander then trimmed all to the same overall length, then cleaned up neck thickness with K&M neck turner just to remove thick areas. Then I proceeded to neck size and load and shoot. All went well until after the cases were fired and neck sized for the second loading.
This is where the problem came into play. I cleaned the cases and neck sized as usual but the necks are flairing out about .010 in diameter at the very edge of the mouth for a length of aprox .040 to .050. The remainder of the neck length has retained its sized diameter, it is only on the very end of the mouth that is flairing.
Any ideas on a fix? Annealing???