why is my seating die crushing my brass?

[Bc'z]

Looks like an uncircumcised.308

It was really cold that morning.

 

[Dave M.]

So u have .012 neck tension? Thats alot.

That’s a ton of neck tension….and this is coming from a guy that preaches higher neck tension.

 

[Shutstr8r]

Alpha brass is thicker in the neck, I’d change my bushing. Sized neck, unless it is a tight chamber should be .268-.269”. May have to make a clean up pass on the necks.

Did you, by chance, decide to remove an expander from your sizing die? Can't do that, as the die is intended to size small, then the expander opens the case mouth back up. If you run it without the expander, the case mouth will be way too tight.

I cannot speak for Forster dies, but on all my sizers ( all Redding full length bushing dies) I took out expander ball and use the mini ball and control the nec size with the bushing. My runout on all of my ammo that I have loaded is .001”. I started doing this after an old benchrester told me that taking out the “ball” expander on a bushing sizer allows the necks to remain more straight.

Just my opinion,

-Darrell

 

[DukeDuke]

I ordered a Wilson bushing die.

 

[tsyarnall]

^^^ I would agree with Shutstr8t on the last part of this, that removing your expander ball many times will help in runout. I haven’t followed all of this, so I could have missed something. However, I would caution you against using a bushing only to control you neck size and neck tension. Unless you have turned the necks of your brass, you are asking to have a lot of uneven neck tension. I, personally, agree with removing your expander ball; size your brass down a .001 or .002 below your desired neck size/tension with your bushings; and use an expander mandrel to set you neck size/tension at your desired amount (minus any spring back).

 

[DukeDuke]

I sized the brass without the expander, but due to the thicker neck walls of the alpha brass, after sizing the inside neck diameter is kind of small and creates a lot of resistance during the seating, thus the crushed shoulders.
Thank you all for your time and help!!!

 

[rocketron]

if the step in the neck in post #15 is not there after you size the brass and shows up after running it in the seater the neck dia. in the die is smaller than the brass dia. If it is there after sizing the unsized part may be larger than the seater dia.