ID help please

[Fred]

Hi there.
I wonder could anyone help me identify this. It is 122mm diameter and approx. 220mm tall with a threaded recess in the bottom, 78mm diameter. It is made from steel with copper plating. At first glance I thought it might be the top of a 120mm BAT drill round but its diameter would be too big.

Thanks
Fred

 

[Bombdoc]

Too thick for a HESH nosecap I would think..

Any markings? I notice the two divots from a hardness tester, so it would look like something that has been heat treated..

 

[Fred]

The only markings are 4.8" which equates to 122mm and SS. My best guess is that it might be a TP nose for a rocket. I wonder if it is ordnance at all. it looks sort of similar to piercing dies used to form seamless tube.
fred