[Edsel]

Unfortunately, I can corroborate knowledge2you's findings on
h**p://www.youtube.com/watch?v=pcc91NArteQ

Skip to ~ 3:30 and ~ 9:55.

The surface is highly ridged, and quite abrasive to brass.

Turn the volume way up and listen to the saccadic, gritty tone.

It's almost like using a file on the case lips.

 

[Flash LB]

I use Redding dies for my precision rifles, but nothing else and I guess it turns out that's a good thing as there's no expander die. Thanks, Edsel, and the first video has been disabled by the owner.

 

[Edsel]

...the first video has been disabled by the owner.

Oops.

Try...

h**p://www.youtube.com/watch?v=pcc91NArteQ​

...instead.

The link has been partially crippled to prevent parsing; fill in the asterisks.

The interesting points are at ~ 3:30 and ~ 9:55.

Same effect a defective (insufficiently polished) expander mandrel had on my .308 Winchester brass.