A Gift

A friend rocked up to me at the gun club today with some packets of blanks he said he was going to give me.
I was pretty happy with them as the packets are pretty much unblemished and Black Powder ones, I have CAC packeted ones and Kynoch S.A packets but never Black Powder ones.
I am not going to open the packet/s to gecko a round the only thing I could find on the packet was 24 1 or I and J.
What does this mean RCS you may have an idea 1924 Jan Lot J! I thought black powder was well and done by then.

My friend says he received 30 packets just like these from a gun store and was handing them out to his friends that collect 'munitions I am very well pleased.
Any information you can supply on them is as always appreciated by myself as I learn as well. TIA