Chris,

That is a very nice rifle and glad you got it. Concerning case and scope mounts, Axel can elaborate better than I can but I will try below.

If a 360BPE case does not enter fully, I suspect the chamber is for the German case head (D) which is smaller than the English case (E case).

The 9.3x72 brass that I have appears ton have the English head diameter. I have had to thin the head @ the web using a small lathe and then resize the case by pushing it all the way into my 9.3x72 dies without the shell holder.

Triebel scope mounts are different from the more normal claw mount. I have a double rifle with the same scope mounts. Axel provided a great explanation of how they function. The lock potrion of the mount is in the rear where there are double post where the back post is movable and locks the mount system. Itt is easier to understand by looking at your rifle. I checked with NECG and they will not build scope mounts for Triebel system. I toyed with the idea of making mounts but have not gotten further.