Trade Pyrodex RS for Real Black Powder

Hello, I have close to a pound of RS Pyrodex Black Powder Substitute, which is the equivalent to FFG powder. I would like to trade it for an equal or nearly equal amount of real FFG Black powder of any brand (Goex, Swiss, etc.). This bottle is opened, but has been properly stored and is only missing roughly 1000 grains from it. I am only considering trades for black powder. Thanks!