That shape reminds me of the blivet to carry baggage on our F-4B/J aircraft during cross country flights.
They bolted onto the inboard LAU-17 pylons with the pointed end forward, and were equipped with a forward and aft access Dzus fastened doors.
There were two gotchas to be aware of when flying with the thing.
- If ordnance mounted the blivet with the pointed end aft, your main landing gear was going to hit it on retraction.
- If you didn't get the Dzus fasteners properly closed (and they were usually poorly maintained) your baggage was going to be distributed throughout the countryside.
It would make sense to use a readily available overstocked item in the military supply system. As I recall, the source of these blivets was the military overhaul facilities for the F-4.