Not sure what this is. Artillery Primer?
It has a steel head and the paper is thicker than a shot shell.
Larger than 36 gauge & smaller than a 32 gauge.

Hi Bruce, don’t know what it is but can tell you there are at least two of them.

The base of the head and the primer pocket appear to be hand shaped, Filed & drilled . Perhaps a home made shot shell to fit a firearm chambered for another round? India , or that region? Just a WAG.