Happy2Shoot Wrote:Incorrect statement. Your die sizes your necks the same, with or with out the mandrel. Size-dies squeeze necks down a lot. Die makers don't know how thin or thick you brass necks are. Then the button is dragged back out of the case, expanding the neck 0.003" or so under bullet diameter. I use a M-die on my press during the loading process and skip the button in the resizing operation. What is your OD with a bullet seated?
Happy,
I don't think this is an issue of correct or not, you both seem to understand what is happening.
The crush without the stem is different depending on the manufacturer, and this imparts different neck tensions also depending on how thick your brass is at the neck .
These are my measurements based on Lapua brass which loads to an OD of .2900"
Forster
With expander, neck OD .2865. Neck tension is .0035"
Without expander, neck OD .2860. Neck tension is .004"
Redding
With expander, neck OD .2895. Neck tension is .0005" (too light for an auto loader)
Without expander, neck OD .2800. Neck tension is .01" (too severe to be usable)
The Redding works the neck more than the Forster.
For AR's we need neck tension so .004" is the Forster without the expander.
For bolt guns I would prefer the Redding with the expander, .0005", although the Forster with expander would work too.
I understand Lee works necks even more than these two.
Brian, what die to you currently have?