These guys are in Minnetonka, MN : http://www.gunstop.com/
I ordered some .458 SOCOM brass and they sent me .460 S&W by mistake.
I called them the next day, they checked the invoice number, and immediately told me they would send out the right brass along with a return label for me to send them back the incorrect brass. Within minutes, I received an email with tracking info for the new package.
Now that's customer service.
