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This graph shows different pressure curves for powders with different burn rates. The leftmost graph is the same as the large graph above. The middle graph shows a powder with a 25% faster burn rate, and the rightmost graph shows a powder with a 20% slower burn rate. Energy is the ability to do work on an object. Work is force applied over a ...
Various different powder are produced and are given numbers to distinguish them. The different types of powder typically have different burning rates. Due to the construction of metallic cartridges, different amounts of powder of different burning speeds are used to obtain optimum performance and accuracy. [8]
A substance is characterized by a burn rate vs. pressure chart and burn rate vs temperature chart. Higher burn rate than the speed of sound in the material (usually several km/s): "detonation" A few meters per second: "deflagration" A few centimeters per second: "burn" or "smolder" 0.01 mm/s to 100 mm/s: "decomposing rapidly" to characterise it.
For pure explosive damage, high burn rates or detonation speeds (and accompanying brisance) are generally preferable, but in guns and especially cannons, slower-burning powder decreases firing stresses. This allows for lighter, longer (and more accurate) barrels with associated decreases in production and maintenance costs.
The C was to indicate the powder burned "cooler" than traditional Improved Military Rifle (IMR) powders. [4] In 1949, he began acquisition of powder salvaged from disassembled Oerlikon 20mm cannon cartridges. This powder resembled IMR 4350 in appearance, and with a slower burning rate, was initially marketed as "4350 Data", and later as 4831. [5]
By manipulation of the shape it is possible to influence the burning rate and hence the rate at which pressure builds during combustion. Smokeless powder burns only on the surfaces of the pieces. Larger pieces burn more slowly, and the burn rate is further controlled by flame-deterrent coatings that retard burning slightly.
Black powder produces gas at a predictable rate unaffected by pressure, while the gas production rate of smokeless powder increases with increasing pressure. [6] The possibility of runaway pressures caused smokeless powder to destroy many firearms designed for black powder and required much more precise measurement of propellant charges.
Smokeless powder burn rate; Primer strength; Cartridge case volume; Because of these factors, it is possible to have two loads where each is propelling the same bullet weight at the same velocity, but one is a standard pressure load and one is a +P load.