Mortar Auxilliary Charges

I show three mortar auxilliary charges for British 3" mortars.
These fit under the tail springs and are ignited by the primary shell when the range need to be adjusted. They are approx. 56mm long. 18.6mm diameter.
They are a celluloid type material and two seem to contain Ballistite?
The other may be gun cotton?
The top label shows Australian loded by ME 1/43.
The other one has a black broad arrow on it.