Editing Flash suppressor (section)

==Rationale==
Pre-20th century [[rifle]] designs tended to have longer barrels than modern rifles. A beneficial side effect of the long barrel is that the propellant is completely burned before the bullet leaves the barrel, usually resulting only in a puff of smoke from the muzzle. However, if the same weapon's barrel is "cut down" (shortened), as is common in [[cavalry]] and jungle-combat adapted versions, the bullet would often leave the barrel before the powder was completely consumed, resulting in a bright flash from the muzzle.<ref name=Maio/>

When barrel lengths were dramatically decreased with the introduction of various shorter-barreled rifles and carbines, the flash became a serious problem during night-time combat, as the flash would impair the shooter's [[night vision]] and would also make the shooter's position more apparent.<ref>{{cite journal |title=The Army Adopts a New Rifle |last=Perkins|first=William |page=149|journal= Popular Mechanics|year= 1958|volume=109 |issue=1}}</ref> Originally limited to "special purpose" roles, it was now expected that all infantry weapons with shorter barrels would experience this problem, and thereby be of limited use in low-light situations. Flash suppressors became common on late-[[World War II]] and later [[assault rifle]] designs, and are almost universal on these weapons today. Some designs such as those found on the [[AKS-74U]] serve a dual-role as a gas expansion chamber helping the shortened weapon's gas system function properly.<ref>{{cite book |last=Rottman |first=Gordon |title=Kalashnikov AK-47 Assault Rifle |date=19 April 2011|publisher=Osprey Publishing |isbn=978-1-84908-462-8|page=35}}</ref>

Military flash suppressors are designed to reduce the muzzle flash from the weapon to preserve the shooter's [[night vision]], usually by diverting the incandescent gases to the sides, away from the line of sight of the shooter, and to secondarily reduce the flash visible to the enemy. {{Citation needed|date=February 2020}} Military forces engaging in night combat are still visible when firing, especially with night vision gear, and must move quickly after firing to avoid receiving return fire.

Limiting the amount of powder to what the length of a barrel can burn is one possible solution, but differences between individual cartridges mean that some cartridges will always have too much powder to be completely consumed, and the reduced powder load produces a lower projectile velocity.  Muzzle flash can be controlled by using cartridges with a faster-burning propellant, so that the propellant gases will already have begun to cool by the time they exit the barrel, reducing flash intensities.  Faster-burning powders, however, produce less projectile velocity, which reduces the accuracy, due to introducing a more parabolic bullet flight path in place of a "flat" trajectory, while also reducing the lethality of the weapon by reducing the distance of the projectile's penetration of the target.

Flash suppressors reduce, or in some cases eliminate, the flash by rapidly cooling the gases as they leave the end of the barrel. Although the overall amount of burning propellant is unchanged, the density and temperature are greatly reduced, as is the brightness of the flash.<ref name=Maio/>