Flash and methods for suppressing it

The discharge of a gun is almost always accompanied by a glaring flash which at night discloses its position. Experiments, particularly using cine-films, give the following picture of how flashes arise. 

The primary flame in the form of a dark-red taper is created by inflammable gases escaping from the bore. These gases mix with the air to form an inflammable mixture. If the temperature of the mixture is sufficiently high, it ignites at the end furthest from the muzzle (Fig. 190). 

The burning of the mixture may end with an explosion (detonation) if its composition is suitable. The explosion of the gas mixture is accompanied by a bright flame. This secondary flame is elliptical and visible for a great distance. The dimensions of the flame and the intensity of the flash depend to a great extent on the calibre of the gun e.g. a shot from a 30 cm naval gun gives a secondary flame up to 50 m long, visible for a distance of 50 km. 

The following circumstances favour the formation of a secondary flame  

On the other hand the presence among the products of explosion of substances that prevent the explosion of the gas mixtures reduces the possibility of the secondary flame. 

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