Methods of making cross sectional, functionally-graded munitions propellants exhibiting various distributions of particle concentrations and burn rate, including having a fast burning core and slower burning outer layer(s). Unlike prior art methods of preparing such munitions, propellants prepared according to our inventive method(s) may be performed substantially as a single extrusion step or as a few processing steps, without requiring the time, expense and/or difficulties that characterized familiar, laminating methods and methods which use multiple extruders. Our inventive method advantageously employs a demixing phenomenon that, prior to our inventive application and teaching, has been considered quite undesirable in the preparation of propellants where uniformity and well-mixedness have been propellant attributes widely sought after.