The gas tube for an AR-15 is part of the firearm's gas impingement system. In this system, the primer ignites the powder inside the casing, creating an explosive reaction that propels the bullet. The pressure and energy produced by the explosion operate the system through a cycle involving...
When you fire your AR-15, the powder inside the cartridge is transformed into energy that propels a projectile. There is a flash of super-hot gasses and unburnt powder coming out of the end of the barrel as a secondary effect of the firing. Such a flash is especially evident in short-...