Muzzle Flash
The visible flash of burning gas at the muzzle when a shot is fired, reduced by a flash hider and by certain powder formulations.
Muzzle flash is the bright burst of light seen at the muzzle as hot, partially burnt propellant gas mixes with oxygen in the air and ignites. Its size depends heavily on the powder and how completely it burns inside the barrel, so a short barrel or a slow powder that is still combusting at exit tends to produce a larger fireball. Flash matters most in low light, where it betrays position and bleaches the shooter’s night vision.
The most direct countermeasure is a flash-hider, which cools and disperses the gas before it can ignite into a visible bloom. Flash-reduced or flash-suppressant powders, often loaded with additives that lower the burning gas temperature, further dim the signature, which is distinct from the separate problem of muzzle-blast concussion.