Right now I'm carrying the Cor-Bon because I can't find the Pow'R Ball anywhere in town, but if it buys even an extra two inches of penetration over the Cor-Bon, that puts it in the FBI's "acceptable" category, if only minimally, yet it still would maintain some expansion capability.
In the meantime I think alternating rounds--Magtech FMJ and Cor-Bon DPX (both of which feed 100 percent reliably in my LCP) in the magazine is a good idea.
Thanks for the feedback.