I have recently found this dummy, steel case, green lacquered, headstamp MR 001 75 PY. The projectile has a light alloy dummy fuze stamped: “inerte”. The projectile body is stamped: “180 INERTE 4 92”. The projectile was painted a light brown colour, there is a 6.5mm hole in the case. A tie-bolt from the primer pocket is screwed into the projectile.
It may have been used for trials with a Naval Close-in-Weapon-System as it came from a shipbuilding town. Any information on origin please?