A muzzle blast is an explosive shockwave created at the muzzle of a firearm during shooting. Before a projectile leaves the gun barrel, it obturates the bore and "plugs up" the pressurized gaseous products of the propellant combustion behind it, essentially containing the gases within a closed system as a neutral element in the overall momentum of the system's physics. However, when the projectile exits the barrel, this functional seal is removed and the highly energetic bore gases are suddenly free to exit the muzzle and rapidly expand in the form of a supersonic shockwave (which can be often fast enough to momentarily overtake the projectile and affect its flight dynamics), thus creating the muzzle blast. The muzzle blast is often broken down into two components: an auditory component and a non-auditory component. The auditory component is the loud "Bang!" sound of the gunshot, and is important because it can cause significant hearing loss to surrounding personnel and also give away the gun's position. The non-auditory component is the infrasonic compression wave, and can cause concussive damage to nearby items. In addition to the blast itself, some of the gases' energy is also released as light energy, known as a muzzle flash. Components Gun sound The audible sound of a gun discharging, also known as the muzzle report or gunfire, may have two sources: the muzzle blast itself, which manifests as a loud and brief "pop" or "bang", and any sonic boom produced by a transonic or supersonic projectile, which manifest as a sharp whip-like crack that persists a bit longer. The muzzle blast is by far the main component of a gunfire, due to the intensity of sound energy released and the proximity to the shooter and bystanders. Muzzle blasts can easily exceed sound pressure levels of 140 decibels, which can rupture eardrums and cause permanent sensorineural hearing loss even with brief and infrequent exposure. With large guns with much higher muzzle energy, for instance artillery, that danger can extend outwards a significant distance from the muzzle, which mandates wearing of hearing protections for all personnel in proximity for occupational health purposes. For small arms, suppressors help to reduce the muzzle report of firearms by providing a larger area for the propellant gas to expand, decelerate and cool before releasing sound energy into the surrounding. Other muzzle devices such as blast shields can also protect hearing by deflecting the