Smokeless powder

Smokeless powders was introduced as a black powder replacement in the 1880's.
Besides generating a lot less smoke, smokeless powder burns much cleaner and more efficiently than black powder, greatly reducing powder fouling and increasing the performance of the shotgun, handgun, and rifle cartridges in which it is used. It is also much safer to produce than black powder, which has saved many lives over the years.
Smokeless powder consists of nitocellulose (single-base powders), frequently combined with up to 50 percent nitroglycerin (double-base powders), and sometimes nitroglycerin and nitroguanidine (triple-base), corned into small spherical balls or extrudedinto cylinders or flakes using solvents such as ether. Other minor ingredients, such as stabilizers and ballistic modifiers, are also added. Double-base propellants are common in handgun and rifle ammunition. Triple-base propellants are more common in artillery guns.
Smokeless powders are made in three forms:
1. Thin, circular flakes or wafers
2. Small cylinders
3. Small spheres
In addition to being classified by shape, smokeless powders are generally grouped by application based on their burning rate and properties. There are handgun powders, shotgun powders, and rifle powders.
Smokeless powder burns only on the surfaces of the granules. Larger granules burn more slowly, and the burn rate is further controlled by flame-deterrent coatings which retard burning slightly. The granules are also coated with graphite to prevent static electricity sparks from causing undesired ignitions. Graphite is used as a coating to facilitate powder handling, and it is this graphite coating that gives smokeless powder it typical gray color.
All smokeless powders are extremely flammable . Smokeless powders, once ignited, will burn rapidly and vigorously until they are completely consumed. They provide their own oxygen for combustion and cannot be extinguished by depriving them of atmospheric oxygen. Oxygen from the air is not necessary for the combustion of smokeless powders since they contain sufficient built-in oxygen to burn completely, even in an enclosed space such as the chamber of a firearm.In effect, ignition occurs when the powder granules are heated above their ignition temperature.
This can occur by exposing powder to:
1. A flame such as a match or primer flash.
2. An electrical spark or the sparks from welding, grinding, etc.
3. Heat from an electric hot plate or a fire directed against or near a closed container even if the powder itself is not exposed to the flame.
When smokeless powder burns, a great deal of gas at high temperature is formed. If the powder is confined, this gas will create pressure in the surrounding structure. The rate of gas generation is such, however, that the pressure can be kept at a low level if sufficient space is available or if the gas can escape.

Smokeless powder differs considerably in its burning characteristics from common "black powder." Black powder burns essentially at the same rate out in the open (unconfined) as when in a gun. When ignited in an unconfined state, smokeless powder burns inefficiently with an orange colored flame. It produces a considerable amount of light brown noxious smelling smoke. It leaves a residue of ash and partially burned powder The burning rate of smokeless powder increases with increased pressure.
If burning smokeless powder is confined, gas pressure will rise and eventually can cause the container to burst. Under such circumstances, the bursting of a strong container creates effects similar to an explosion.
Temperature also influences the burning rate of smokeless powders.