WHAT DOES BLACKHORN 209 POWDER IN STOCK MEAN?

Blackhorn powder is palms down the cleanest and very best capturing powder which i've ever applied! I'm taking pictures 80grn by quantity with hornady xtp 240s and they are tack motorists at 100yds! I haven't had a misfire applying Blackhorn 209 and Winchester W209 primers!It’ll operate with pellets or powder. They suggest the BH209 breach plug b