LAST EDITED ON Jul-28-17 AT 04:41 PM (MST)
Is it the brass or perhaps one of your reloading steps that's giving you fits? Some of us could help (if you want) if you'll walk us through what's happening.
Note: make sure your seater die isn't screwed into the press so deeply that it wants to "crimp" the brass onto the bullet. This will make you bullets loose and also poor fit in the chamber unless the bullet is designed for it and crimping is not necessary. If you think this MIGHT be it we can walk you through setting it.
Have you measured the brass thickness or at least compared the OD with brass that works?
I cannot imagine brass that thin when loaded with a conventional die set.
On the other hand, if this is too much info and NOT what you want please just tell me that I'm full of sh!t and I'll move along quietly.