Could someone explain to me how these things work and how do I select the right size for best accuracy.
Let me expand a bit:
I'm shooting cast lead bullets and unsure about what is the best neck tension on them.
If I'm understanding correctly, a person measures the OD of a loaded round and calculates down a few thousanths for the right size. The difficulty comes in when I'm shooting lead (GC) bullets with no crimp and I've found that a bit tighter neck works a bit better. If I measure the OD I'll still get the same measurement, but I won't have a good handle on the "grip" of the mouth to the bullet.
I've posted this message in a couple of places. (setting tip-ups)