[prickett]

I'm loading 9mm and 40 S&W and I'm looking for one powder to do both. I thinking of using either WSF or 231 powder.

Any opinions?

I use both. WSF, for whatever reason, is getting harder to find. W231, on the other hand, is also marketed by Hodgdon as HP38 (the Hodgdon powders tend to be cheaper than Winchester's).

I've not been unhappy with either.