In reloading there are several basic components. One of those components is the gunpowder, often just referred to as powder. The gunpowder used for a given caliber differs in a few manners. These are commonly broken down to burn rate, density and particle shape.
The focus of this piece will be on particle shape. The shape of a powder is determined by the method used to manufacture it. It also significantly affects burn rate, charge density and simplicity of metering the charge.
The common powder shapes are:
Ball – This is a spherical powder that meters extremely well. The burn rate is somewhat affected by the size of the balls. The larger spheres burn less quickly than smaller spheres.
Flattened ball – These are very similar to ball powders, but have a bit less consistent metering and can have some disparity of burn rate due to lack of particle size uniformity.
Flake –These are powders that range from a disk shape to a cereal flake shape. The disk shaped versions of this powder type meters better than the cereal flake type and they also have less variance in burn rate. This type of powder tends to be bulkier for the same throw weight of powder. It also tends to be more affected by compression as the flatter shape is more fragile and does not compress uniformly. This is also a function of the disk size and thickness, so some variants are more or less affected.
Stick – this is a powder that is extruded through a die and cut at a set length. These powders are typically used in slower burning applications and meter moderately well. Some manufacturers have made “SC” versions of certain powders. “SC” stands for Short Cut, to help them meter more consistently. This affects burn rate as the increased surface area will create a slightly faster burn rate if not offset in some other manner.
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