Small centerfire shotshell

I have gotten this small blue paper rolled shot shell with an 8 on the overcard

rim diameter .4435 " 11.27 mm

base diameter .3835 " 9.74 mm

case length 1.64 " 41.66 mm

the centerfire primer takes up most of the base.

no other markings

Any Idea’s Thanks Vic

9 mm Center Fire