A great many stories have been told about the noiselessness of smokeless
powder. But there is no such thing as a noiseless gunpowder. The report
of a gun charged with smokeless powder is very sharp, and is as loud as
when black powder is used, yet the volume of sound is much less, so that
the report cannot be heard at so great a distance.
The report of a gun using smokeless powder is a sound of much higher
pitch than when black powder is used, and consequently cannot be heard
at so great a distance as the lower notes given by black powder.
As smokeless powder exerts a much greater pressure than common black
powder when burned in a gun, one would naturally think that the recoil
of the barrel would be greater, owing to the greater pressure exerted by
the smokeless powder on the base of the cartridge case and the breech
mechanism. However, such is not the fact; for the barrel actually
recoils very much less when smokeless powder is used. This is due to the
suddenness with which the pressure is exerted by smokeless powder, it
acting more like a very sharp blow on the metal, whereby more of the
energy is converted into heat instead of being spent in overcoming the
inertia of the barrel to give recoil. Similarly when smokeless powder is
fired in a gun, the displacement of the air is so sudden that the sound
waves do not possess the same amplitude of recoil or vibration as is
given by black powder.
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