Probably a 9.3 BP cartridge . Veterilli (sp).
It could as easily be for a 38 Colts (pick one) 1873-86 , H&R among others brought the 38 short forward with a .361 groove .
.365 would be a Russo hand gun dia but 150 is pretty heavy for the 9×18 .
I'm sure there were some 9.5s but I can't think of any of the top .