A Big Thanks to Gamestalker for his help.
When Dillon rebuilt my 650 this Spring, I had them install and adjust a set of .380 dies.
Well, they said they'd adjust them using the fired brass and sample bullets I supplied, in actuality they just screwed the dies into position and didn't adjust anything. They actually loaded a couple of dummy rounds with the FMJ bullets seated backwards, like a .380 wadcutter.
The dies they supplied are called the "New Dynamic" version, which includes a spring-loaded decapper which snaps downward when the old primer comes out of the pocket, and flings it into the catch cup. That's supposed to work better with military crimped primers, which is kinda useless with .380
I suspect that the strong spring which flings the decapper assembly downward, is causing it to hit the inside bottom of the case and causing the problem which Gamestalker describes. The old style fixed decapper fits properly and doesn't come close to hitting the bottom of the case, so I'll try loading some ammo with that system when I get some time.
