Gun powders
The manufacture and distribution processes for gun powders are significantly different from those of explosives. Approximately 2 1/2 million lb of black powder and 20 million lb of smokeless powder are produced for commercial use each year. Most of the smokeless powder is used in fixed ammunition for rifles, pistols, and shotguns, would not be sold to users as an end product, and would not be tagged under S. 333.
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The basic process for the manufacture of gunpowders involves the following steps:
- mixture of ingredients, which may include the raw ingredients as well as surplus and reworked powders;
- granulation, where the “dough” is extruded, chopped, or otherwise granulated to form the various grains;
- screening of grains into designated sizes; and
- blending of various batches to get the desired ballistic characteristics.
In the smokeless powder manufacturing process, nitroglycerine, nitrocellulose, and other additives are combined to make various grades before the blending process. Smokeless powder grades therefore differ due to size differences and composition differences (various amounts of nitroglycerine), while black powder and black powder substitutes such as Pyrodex vary only by grain size. In a given grade of powder, variations in density and other fluctuations during the manufacturing process can cause considerable variations in the ballistic properties of the final powder. As the handIoader generally has no means of controlling his ballistics other than the weight or volume of powder added, the ballistic properties of a particular grade of powder must be carefully controlled by blending. A given brand name product may therefore contain parts of several batches, blended like brandy to give the desired ballistic properties. Several sequential blending operations may be necessary before the product meets the required specifications. If the ballistic properties of a particular batch or blended lot are too far off, the material must be reprocessed or used for something other than hand loading
If taggants are added to gunpowders, they may have to be added at different stages in the manufacturing process for different manufacturers, due to the differences in blending and reworking processes. As an example, at one smokeless powder factory that makes powder for both handloading and fixed ammunition, taggants could be added during the blending stage; blended batches that were still not satisfactory could be used for fixed ammunition. At another factory, due to their large rework factor, an additional taggant mixing stage might be necessary. For some products, it may be possible to add taggants to the dough, although this may affect the granulation process and present blending problems. p22-23