That said, I don't think I would be trying to alter chambers and stuff like that.
My concern would be pressures. My Hodgdon manual shows .380 at a max pressure of 16,100 CUP. But the 9mm goes up to 32,500 CUP. I would not want to be the guy trying to shoot a cartridge that produces twice the pressure a gun was designed for. I do like all of my fingers though. Maybe that's just me?
Romans 1:16 I am not ashamed of the gospel, because it is the power of God for the salvation of everyone who believes: first for the Jew, then for the Gentile.