Well, I have often wondered what the conversion is ( I wanted to use the G7 drag function with my Matrix VLD Bullets), and well, after a long search I came up with zilch.
However, I did realize something. The data is there to derive my own "equation"
Using the Litz Test data in this document
www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA554683 , I would estimate that the G7 value is almost exactly 1/2 of the G1 value.
The actual magic is what occurs within the variables inside the G7 Drag finction.
There is one caveat tho, this conversion ONLY works with VLD bullets that have a tested G1 and G7 BC. It would not work when trying to get a G7 bc from a flat based G1 only bullet