This research determines how particle size and particle distribution affects the compaction of granular beds. A modelling and experimental effort was recently designed to compare the compaction behavior of two types of granular HMX: prepressed conventional (coarse) HMX material (mean diameter of 40μm) and microfine HMX (mean diameter <5μm) [M. Greenaway, Journal of Applied Physics 97, 093521 (2005)]. The microfine material demonstrated higher levels of granular bed strength. Mesoscale modelling of granular beds that are of fixed initial solid volume fraction but vary in particle size and distribution have been undertaken that include a simple elastic-plastic strength model. These suggest that it is not inherently the “size” of a particle that controls the bed strength but the morphology and distribution of particle grains. These solutions are compared with the behavior predicted from continuum scale models of material compaction.