My first question would be is the 9.3 X 82 the straight case or the Thieme & Schlegelmilch Nimrod version? Reason I ask is my T&S in 9.3 X 75R Nimrod is a bottleneck case. Unless I'm mistaken, entirely possible, the Nimrod cases were proprietary and bottlenecked. If you haven't I believe I'd do a chamber cast first. If you have and know obviously I am out of line and apologize.
For brass Graf's has 9.3 X 82R in stock. Pricey but they have it. I used it to form my 9.3 X 75R Nimrod....very carefully at that price!!
https://www.grafs.com/retail/catalog/category/categoryId/825?
