I have a US made 20mm Oerlikon drill round headstamped “A.S.C. 1943 20 MM-MK-2”. I know the case maker. The fuse is marked “MK.XXVI.MOD.?.MBCo.LOT”. I cannot make out the model number. Who was “MBCo”? 26 marks seems an awful lot. The projectile body is marked: “MK 4-23 D 7-42”. Is “D” the maker’s mark on for the projectile? If so, who was it? Any info would be helpful.