I am going to buy a redding s type neck bushing die for 257 roberts ai.
Have measured the out side neck diameter of set of newly fire formed cases.0.283 remmington.
Measured the cases ive been using for last 12 months which are winchesters 0.285.
All cases where measured when loaded. all shot in my own gun.
do i go with the size of newly fire formed cases and order bush -0.001"