Hi Pinotguy:
I do have a 7x66 SEVH
My opinion after 2 years of reloading efforts is that you will not get what you can get with the new 7mms.
And ... the brass is really expensive and very dificult to replace with other calliber, I transform some 300 ultra cases ,but it was really dificult to obtain the cases for the 7x 66.
I think that there are a lot of other callibers ofering beter perfomance.
My rifle is a Mauser 66
If you want my files send me your e-mail and I will convert them from spanish to english for you
Sincerelly yours
Guillermo Trotz