Very rare WWII German Armorer's Tool Round for Solothurn 20x138b long weapons as used in the Flak 30 and 38 guns. This is a tool cartridge for testing function and spacing, it is not a training dummy. There is some chrome loss and rust where the chrome used to be. The head stamps are: H39 (1939 production) at the 12 O'Clock position, Waffenamt at the 3 O'Clock position, and maker's mark logo at the 6 O'Clock position.