Do some research. When I was working audio for my sound pack I tried to find sources of the original equipment for just about everything. The MK108 30mm audio or gun cameras of any sort from WWII in combat do not exist in any accessible form. You can check with anyone you want (Smithsonian, Dayton, etc.). If it exists at all it will be in cold storage in Russia, or in a private collection. At this point it would be priceless, so I wish you luck.