Do you mean that after you size the .30-30 cases in the 7-30 die, you get what looks like two shoulders - one just above the other?
Because that's perfectly normal. The 7-30 has a shorter neck (or has the shoulder blown forward - depending on how you look at it). When you fire them, you'll see the shoulder has formed perfectly. You'll also see a faint slight bright ring where the .30-03 shoulder used to be.
If that's not clear, I'll shoot a photo and post it later.
I don't have the photos with the original article, but here's the link to my page about the 7-30...
LINK