Perhaps the most important decision in reloading is which powder to choose. I will avoid using the term “gunpowder,” as the purists out there will point out that this term should be reserved for what is usually referred to as black powder, the original gunpowder.
Modern cartridge based firearms use so-called “smokeless” powder as the propellant, so that is what I will be discussing.
Modern smokeless powders are composed of one or more basic explosive compounds. Single base powders utilize nitrocellulose, double base powders use nitrocellulose and nitroglycerin and triple base powders use nitrocellulose, nitroglycerin and nitroguanidine. Single base powders tend to deteriorate quicker as they are hygroscopic, that is they absorb moisture and break down. Whilst single base powders are still commonly available, the benefits of double base powders make them attractive to reloaders due to their superior storage capabilities. Unless you are planning on reloading 5” naval shells, you are unlikely to need a triple based powder.
Various additional compounds are added to the base compounds to control burn rates, slow degradation and reduce flash, among other characteristics.
Figure 1 shows the ingredient label for Alliant’s Blue Dot powder, a common double base shotgun and magnum load powder.
Physical Nature of Powders
Smokeless powder may be produced in several physical forms. These may be small balls, flakes or extruded rods. The various physical forms are designed to provide different burn rates, with ball powders generally burning fastest, then flake powders and finally rod powders, although the additives in a specific powder may change this somewhat.
Fast burning powders produce a quick snappy load which may be suitable for short barrel firearms such as handguns. Slower powders are often used for long arms, particularly those of large calibre. Gas operated firearms need more gas to operate, which may mean a slower burning powder. The moral of the story, all powders are different, and each has its uses.
Choosing a Powder
A quick check of the Internet indicates that there are several hundred smokeless powders commonly available. Most industrialized countries seem to have some capability to produce their own propellant powders. Selecting a powder manufactured in your own country will most likely improve availability and reduce cost.
The best place to start is with a good set of reloading tables or a projectile/powder manufacturer’s data.
There will probably be several powders from each manufacturer which are suitable for a specific application. The final choice is most likely to be dictated by:
- Caliber and type of firearm.
- Specific projectile to be used.
If you are reloading for several different calibers and/or projectile types, it may be prudent, although not always possible, to select a powder that suits all your loads. This will reduce the likelihood of inadvertently using the incorrect powder in a specific load or accidentally mixing powders together. Utilizing one powder also means you can purchase larger quantities of a single type of powder, which has economic advantages.
In practice, enter your reloading data with the specific caliber to be reloaded. Select a load “recipe,” which covers the projectile type/weight you are planning on using, and, if possible, choose one with a powder which is readily available and of an acceptable cost. It may be necessary to research numerous reloading sources in order to get the best combination of powder and projectile type/weight.
Featured image courtesy of ultimatereloader.com