I have been looking for material that has detailed illustrations and descriptions of how the MG213 works. I would also be happy to have the same material for any other revolver type cannon like the DEFA, ADEN or newer versions.
I suppose there is no way to view this film on the internet.
It would appear to be a roll of 16mm film held in their archive, not a digital video. No internet viewing and you'd need to check the licensing page to see whether is possible to view for free even on their premises.