Thread: safe to compress powder during reload?

@johnd I think you might mean hygroscopic.

Hygroscopicity is a general term used to describe a material's ability to absorb moisture from the environment. There is no standard quantitative definition of hygroscopicity, so generally the qualification of hygroscopic and non-hygroscopic is determined on a case-by-case basis

Hydrostatic pressure, also known as rest fluid pressure, refers to the pressure exerted by a fluid at rest due to the column of that fluid above a specific point in it.