I have never duplexed BlackHorn 209. I like that powder, but in all honesty, it scares me a little. Powder like this should not be so good. I am a believer to use things the way the manufacturer says, and you will be all right. One reason I still shoot my old CVA Staghorn instead of leaving it on a shelf because of all the hype about them blowing up.

Now I have used black powder to set off other powders. In a flintlock for instance I was using a little black powder to set off Pinnacle 3f. And it worked real good.

Also there are companies that suggest a little black powder under a pellet will help ignite the pellet in such rifles as the PA Pellet. But I always felt if that is what was needed to get positive ignition, then why not shoot the real stuff.