Inert WW2 Luftwaffe 20mm Round

This is a WW2 Luftwaffe 20mm Round with original ink stamps. The projectile is dated 1943 and has a clear Luftwaffe acceptance stamp in blue ink. The brass cartridge is dated "40" 1940 with the makers initials "BK" which is believed to be those of Metall- Walz- u. Plattierwerke Hindrichs Auffermann AG, Wuppertal. The 20mm rounds were most commonly fitted to German fighters and dive bombers including the Folke-Wulf, Me 109 and Junkers 87 to name but a few.