A method of forming boron nitride nanoparticles. A plurality of precursor molecules comprising boron, nitrogen and hydrogen may be decomposed in a first heating zone to form a plurality of gaseous molecules that contain bonded boron and nitrogen, followed by heating to a second, higher temperature thereby causing the gaseous molecules to react and nucleate to form a plurality of boron nitride nanoparticles. Depending on processing temperatures, the boron nitride nanoparticles may include amorphous forms, crystalline forms, or combinations thereof. Precursor molecules may include ammonia borane, borazine, cycloborazanes, polyaminoborane, polyiminoborane, and mixtures thereof. The boron nitride nanoparticles may be incorporated into a variety of dispersions, composites, and coatings; and in one embodiment, may be a component of a propellant, wherein the boron nitride nanoparticles may confer a range of advantages to gun barrels in which such propellants may be fired.