minimizing case neck runout in rifle brass????

[eschafer]

I'm VERY new to reloading, so new in fact, I've had a RockChucker Kit for 8 months and haven't yet removed it from the box... I've been reading all I can first in preparation...

I've come across frequent suggestions of adding a step to one's process by expanding the neck in a separate step after resizing, but plunging the expander ball into the case (push the ball inside) rather than having the ball yanked out of the case during the typical resizing step....

Those of you that are familiar with this technique, can you please help me understand the advantage why runout would be minimized by eliminating the usual neck expansion while resizing.. would reversing the expander ball not create some other problems such as a "doughnut" at the neck/case junction?? Any help is appreciated.... Thanks..

 

[Eagleye]

It is perfectly OK to leave the expander ball on your decapping unit when FL sizing.....but.....make sure the expander ball and decapper are centered in the die properly.
Then, as long as the brass is of consistent quality, it will not cause off-center necks as the expander is pulled out of the case after resizing.
If case neck have varying thickness, this can cause the off-center neck condition. Pushing the expander rather than pulling it through may lead to less case stretching
during the resizing process, but I have my doubts that it will result in more concentric necks.
Regards, Dave.

 

[hawk-i]

If using RCBS resizing dies I find that putting a O-ring between the die and expander/decapper rod nut allows it to center itself...

 

[hunters home]

When I reload for my heavy barreled rifles and want the less run-out possible I resize in 2 steps. First I decap the cases with a decapping die. Next I remove the decapping pin from my sizing die and leave the expander unit loose and set it up as high in the die as I can without pinching the neck.This way some of the neck is still in the neck portion of the die when the expander enters the neck of the case as I remove it from the case on the down stroke and the "floating" spindle unit is free to find it's own center. I've found this a good way to greatly reduce neck run-out. Another way is with a Redding body die with a Lee collet die, but that's another story..
Hope this helps.

 

[bigedp51]

Forster full length dies with their high mounted floating expander will not pull your necks off center. The neck of the case is helder and centered in the die when the expander enters the case neck. This prevents the expander from pulling the necks off center increasing neck runout.

Below my Redding full length .243 die equipped with a Forster expander and spindle assembly.

I also ordered Forster expander and spindle assemblies for my RCBS dies.

Below a replacement Forster expander assembly for my RCBS .223 full length die on the right.

 

[eschafer]

All responses above are offering very useful and practical techniques that will help me in my journey... Thank you to all... The knowledge these forums offer is invaluable to a beginner like myself... eschafer...