Firearm propellant

Firearm propellants are the chemical substances used to rapidly generate gas causing a pressure difference accelerating a bullet through the barrel of a firearm. Mixtures of different chemical substances are often used to control the rate of gas release, or prevent decomposition of the propellant prior to use. Many propellants use exothermic reactions to generate gaseous carbon monoxide, nitrogen and steam while raising temperatures to increase pressure. The pressure relationships between propellant chemical reactions and bullet response are described as internal ballistics.