That's helpful. So I guess there is no standard.My RCBS die, using the expander ball, was giving ~.003" neck tension.
My Forster die, using the expander ball, is giving ~.002" neck tension.
Yes, of course, I was really just curious.Wouldn’t the consistency between loadings(repeatability of neck tension) be more important than the consistency between different dies?
Makes sense. Thanks.In the context of this thread, the variable most affecting accuracy is runout induced by the expander ball. The neck expands and releases the bullet on ignition before the bullet ever begins to move.
Another aspect to consider is that you are only ever going to get about a spring back’s worth of squeeze on the bullet, which is about half to a thou worth. Sizing your necks down tighter (2, 3, 5 thou, whatever) doesn’t give you more grip. Your bullet just becomes a (crappy) expander mandrel, expanding the brass to cal diameter, and it’s still being held in by the spring back on the brass and the friction between the bearing surface and the sized portion of your neck. Think about what happens when your expander ball sizes the neck back out after sizing. The neck gets a little bigger, and bounces back about a thou. Same thing when you seat a bullet. The neck expands to cal diameter and bounces back about a thou. Anything more is just over working the necks and creating unnecessarily high seating pressures forcing your bullets to expand your necks.