How common is this black bakelite fuze cap on an Australian 20x110 Hispano?
I have only seen two and both were on empty Dummy cartridges.
Headstamped MF 54 20MM both with factory crimps. One has a primer but no powder.
One has MO on the projectile body (Maribyrnong,Vic).
Is it to keep the cavity clean or to be used after filling.
Was this cap also used by UK factories?