 The size and shape of the muzzle flash is dependent on the combustion energy of propellant being used, the amount of combustible ejecta remaining, and any devices attached to the muzzle (such as a muzzle brake, flash hider or suppressor).The muzzle blast is the explosive shockwave caused by rapid expansion of propellant gases when the pressure seal within the barrel previously maintained by the projectile is suddenly removed as the said projectile leaves the muzzle.The blast is often broken down into two components, an auditory component and a non-auditory component.