WHAT DOES BLACKHORN 209 POWDER IN STOCK MEAN?

I've a CVA optima in chrome steel. I even have the black horn 209 breech plug. I load a hundred grains by volume of Blackhorn 209 using a 250 grain Barnes bullet. I have discovered that you actually should use a fantastic primer. Usually do not utilize the primers designed for black powder as this isn't black powder. I utilize the CCI magnum primer