Thanks for your comments. I understand the ramifications of loading for wildcats and obsolete cartridges, and I load for several and form brass of various types; I just don't know the particulars of this one. The Van Horn site you mention is apparently current as of about 2000, and things may have changed. The barrel I am looking at is a Van Horn barrel chambered to 7 mm VH Special, so he must have thought it was safe. Dies come with the barrel. I've emailed Dave to try to get loading data and specifics, but he hasn't responded yet and I was curious.
Maybe someone else will be able to answer my question.
BTW, you actually can gain something from the 7x30 Waters for use in a Contender. Since it doesn't have to survive cycling through an action, you can improve it to use a very short neck and sharp shoulder, more than the typical AI round. I seem to recall that this is what the 7 mm VH Special is, but I'm not sure. If it is built on a .30-06 size case head, I'll pass for use in a Contender.
RonF