Muzzle Blast

This past weekend, I took some video while Damsel was shooting at the range. Apparent in the videos was the flash associated with firing. Also apparent, is the concussion and report. I did some research and found these interesting characteristics associated with Muzzle Blast:

Muzzle blast characteristics

The muzzle blast is often broken down into two components, an auditory component and a non-auditory component. The auditory component, the sound of the muzzle blast, is important because it can cause hearing loss or give away the gun’s position, while the non-auditory component, the overpressure wave, can cause damage to items near the blast.

Auditory

flashes

  • Sound – The sound of a gunshot can be loud enough to produce hearing loss, and with big guns such as artillery, that danger can extend outwards a significant distance from the muzzle. Muzzle blasts can reach levels of 140 decibels, which can cause permanent hearing loss even with brief and infrequent exposure.
  • Overpressure wave (concussion) – The overpressure wave from the muzzle blast of a firearm can contain a significant amount of energy; in artillery, the force of the muzzle blast can cause damage to surrounding structures and vehicles. Residual pressures at the muzzle can be a significant fraction of the peak chamber pressure, especially when slow burning powders or short barrels are used.

Image – Damsel firing (top) the Glock 30
         and (bottom) Smith & Wesson 686

Non -auditory

  • Muzzle glow – Muzzle glow is a reddish glow that is visible before the bullet leaves the barrel. Muzzle glow is created by superheated gases that have leaked past the projectile and have exited the barrel.
  • Primary flashes – The primary flash is caused by propellant gases exiting the firearm behind the bullet. Although amongst the brightest of the flashes, the heat of the primary flash dissipates quickly and thus is no longer visible.
  • Intermediate flashes – The intermediate flash is caused by shock waves created by the high speeds of the escaping gases and projectile, and appears as a reddish disc shape in front of the muzzle.
  • Secondary flashes – Secondary flash appears farthest from the muzzle as a large white or yellow flame. Secondary flash is caused by the mixture of fuel-rich gases and oxygen in the atmosphere surrounding the muzzle.
  • Sparks – Following the dissipation of the muzzle flash, partially unburnt powder or other heated materials can be ejected from the muzzle and appear as sparks.

Not apparent in the images above is the report and concussion. Both the .45 and .357 have a loud report and although the flash appears less intense in the .357, the concussion is significantly stronger than the .45.

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