I made black powder using 98% Pure sulphur, Pharmeceutical grade KNO3, and soft-wood charcoal. I ground it using a mortar and pestle becasue i dont have a ball mill, and when i burn it, its WAAAY too slow. like, i tried to put it in a rocket casing, and it didnt even light. it wouldnt burn at all. its bothering me, becasue i spent alot of money on it, and its not working.