18 pdr part ID

[tigbrand]

To all you 18pdr experts or someone with a handbook! Got this item in a job lot,anyone any idea what its for?? Weighs 325g. Markings are EFM Ld 06 FULL 1918 18pdr. Other inspection marks too. Sorry pics are bad.

 

[hangarman]

Hi Tig,
What are the appriximate dimensions of your thing? I have looked through my 18pdr manual (hasn't everyone got one?) but i cant find anything like it. I can only guess that its a gauge of some sort. Will send the pics to a friend and see if he is any the wiser.
Cheers
Hangarman

 

[Weasel]

Hi Tig,
I have also looked through the book covering Early British Quick Firing Artillery and it has sectioned drawings of every part, still can not find anything that looks like it.
Best Weasel.