Patronen für handfeuerwaffen 1b munition Case

[Australia]

G'day all , I got this today and not sure what period it's from , 23 inches long ,
it's marked patronen für handfeuerwaffen 1b munition , and 12/70 on the side (not sure if it's the year) I've worked out that it's a case small caliber ammunition but that's all (having difficulty with Google )

any further help or comments appreciated .