In relation to other research, I found a reference to a 20mm machine cannon that Yugoslavia was interested in buying in 1939. They seemed to be interested in an anti aircraft mount.
The 20 mm Machine Cannon was a rapid fire autocannon which could be adapted to several tactical uses. There seems to be some confusion regarding the different mounts, so let’s take a look at some of them.
Which mount did Yugoslavia want to buy in 1939? It could be one of the 20mm machine cannons depicted in this brochure from 1936. It is a two page pamphlet/brochure printed on glossy paper by J. D. Qvist & Company in Copenhagen.
There are several pictures of mounts but no explanation to the illustrations besides the DIS code (more pictures in up blog posts here, here, here and here). Each mount has a letter and a number, these were DIS designations or abbreviations of the different mounts. We are sure that there was some sort of price list or other explanation accompanying this brochure.
F.6 – Anti-aircraft mobile mounting for MADSEN 20 mm gun, belt fed
In other sourses the F.6 is mentioned as anti-aircraft mobile mounting.
This Belt fed anti-aircraft machine gun in mount F.6 would have been of interest to Yugoslavia (a number of blog posts on Yugoslavia will follow later). What an unusual and beautiful piece of equipment!
The mount is somewhat special and based on a Belgian request (but apparently Belgium newer bought this model!). It has 2 gunner seats and as usual, one gunner handles the elevation and the other the direction. Both have a sight in front, but it seems that only the gunner on the right was able to fire the cannon due to the Bowden cable visible, from the foot rest (pedal) up to the trigger. Maybe it was easy to shift the cable to the other gunner? This mount was specifically designed as a mobile unit and two axels/four wheels could be fitted (not depicted here).
I have added a closeup of the picture. It is somewhat pixelated as the original picture is quite small. The seat can clearly be seen as can the ammunition belt.
The cartridge in question are the common 20×120 Madsen cartridge.