No kno3 can not burn on its own. it is an oxidixer and needs a fuel to burn. i suggest you start reading some more. Almost afraid to ask how you made your bp. Burn some charcoal and once its red hot put some of the kno3 on it. It should flare up.
O sweet god. I made a 2-1/2" salute with a mix of pyrodex and goex with a flash core and i thought it was loud. i thought I shat myself that day.thinking of a 3" shell filled with flash makes me shake.