The picture below shows a German 151/20mm cannon round. The label which is hard to read states " 20mm MG 151/20 AIRCRAFT CANNON EXPERIMENTAL PRACTICE SHELL FITTED WITH w THERMOCOUPLE" The shell has a hollow nose and the thermocouple fits in and runs right down the inside to the base of the cartridge case. Does anyone know what this is for or how it was used.?
Thanks in advance