Quite a few pyro hobbyists make their own BP and have contests to see who makes the best. It is to pyrotechny what flour is to baking. They judge by how high a standard charge will propel a golf ball from a standard mortar. With the finest grades of sulfur and potassium nitrate and good electric ball mills and sieves, the key to their success is the charcoal. They make their own from various types of wood. They make BP that will outperform commercial.