105mm Tank case recess turned in base

[Falcon]

A friend of mine has this 105mm Tank case. Does anyone know the purpose of the recessed ring turned into the base around the primer? I have seen a few like this before but I've never got round to posting about it.

It probably has a simple explanation? ID of round by feel?

Thanks for any info.

 

[beihan62]

Hi Falcon,Just a guess,is this the insulation between the two contacts for the electric firing,I have one from a Leopard and it is the similar to yours,
Cheers,
Don,

 

[beihan62]

Hi Falcon,Please disregard my last post,I was talking about the wrong ring,Doh!,sorry,
Don,

 

[Falcon]

Just to clarify in case anyone else gets confused, I mean the large ring about half the diameter of the case head.

 

[ozziammo]

Australia made Canister rnds for 105TK, cart case had 2 x concentric rings which ID in poor light conditions as Canister ammo. Maybe same thing but earlier design?

Regards Ozzi.