HP-38 is the same as 231.
Hey, I'm just an internet poster who sometimes can answer little questions. I'm not God!But where does one find this 'black powdered GOLD!'
If it helps you, some other powders that work in all the calibers listed are: Accurate Arms #2, Ramshot Zip, IMR7625, Alliant Unique, Hodgdon Universal, Winchester WSF, Alliant Power Pistol, VihtaVuori N330, AA#5, Hodgdon HS6.
Maybe you will get lucky and find something to substitute, Good Luck