Jeff,
I can not say enough for a chamber cast. I recently purchased a drilling that I was told by the seller was 9.3x72r. After the chamber cast it became clear it was actually a 9.3x82r. There were no proof marks to indicate the cartridge. With Raimey's help, I was able to narrow down the dating of this gun to about 1900.
The other advantage of a chamber cast is that you can later send it off to Ace Dube and have a 22 Hornet insert made for about $70. Mine is currently on order.
Another issue is that there were two 9.3x72r cartridges. Here is a partial listing of potential candidates:
9.3 x 57 R (.360)
9.3 x 65 R
9.3 x 70 R (.360)
9.3 x 72 R (.360)
9.3 x 72 R Sauer
9.3 x 74 R
9.3 x 75 R (.360)Nimrod
9.3 x 80 R (.360)Nimrod
9.3 x 82 R (.360)Nimrod
Pete
