When selecting a powder it is important to consider the shape of the particles called granules. All powder measures achieve their drop weight by filling a cavity or an adjustable vile having a quantifiable volume with powder. The physical shape of the granules are a part of the manufacturing process and due to their physical shape some granules will fill the powder measure more consistently than others. The following is a list of common powder granule shapes in the order of best to worst for metering in a powder measure.
Consists of spherical granules that are normally small in size. This type of powder meters very well.
FLATTENED BALL POWDER
Is very similar to ball powder but is flattened slightly. This type of powder behaves almost identically to ball powder.
Or Stick Powder has granules that are shaped like small extruded cylinders. One issue that can arise with this shape is the powder measure cutting the sticks into different lengths which will lead to slight inconsistency.
Has granules that are shaped like tiny disks. Flake powder is the most difficult to meter correctly due to the fact that it can “stack up” and/or “bridge” in the powder measure making it less uniform when metering.
Lastly, some powders do not meter well. Unique powder for example meters with uniformity. You may find the same symptom with small flake powder in small quantities.