Unknown copper tube like thing.

[Michel]

This may or may not be munition related. I have never seen it but maybe someone recognizes it. It is a copper tube (empty of course) with one end closed and a valve off some kind that opens up in the rectangular openings. I'm thinking smoke but I can be far off. Back ground is almost certain naval, as is comes off a beach.

 

[BMG50]

May be its a fuel cap and filter from a vehicle,

 

[Michel]

As I'am not familiar with those things a couple more pictures. Should the other end of the tube also be open, to let the fuel out ? There is a valve that is now closing off the top of the tube. There was a residue of iron below off the screw on cap, could indeed be where it was mounted in a tank off some kind...
I think you are right with it being a filler cap. I think when the fillercap is unscrewed the closing cap off the tube comes out off its place together with the cap...
so problem solved!!

 

[beihan62]

Fire extinguisher cartridge,?