Combustion converts less than 50 % the mass of gunpowder to gasoline; the vast majority of it turns into particulate make a difference. Some of it is actually ejected, losing propelling electrical power, fouling the air, and usually staying a nuisance (making a gift of a soldier's position, making fog https://greatgotfirearms.com/product/goex-2fg-black-powder-1-lb-in-stock/