Tony Williams, re: C.205's MG 151-20 cartridges

[Wilbus]

Also, in order to cause real dammage from a 30mm slug you'd need it to actually hit something vital (engine or pilot).

Hit a wing or the fuselage and it would basicly just make a 30mm big hole or slightly bigger.
3x12.7 mm would create more "hole" area, not to mention that while you may hit 1x30mm you will probarly hit a whole lota more 12.7mm.

[Tony Williams]

The MK 108 was designed around the concept of maximising blast effect from the high-capacity Minengeschoss shells. It would defeat the purpose of the weapon to use anything else (apart from high-capacity incendiaries in some circumstances).

Tony Williams: Military gun and ammunition website and discussion forum

[Wilbus]

Rgr Tony thanks