Understanding the response of a propellant [1], specifically under dynamic loading, needs (at least) to know its mesostructural morphology and the mechanical behaviour of each of its components. But the scale of the mechanical description of the behaviour of a propellant is relative to its heterogeneities and the loading wave length. The shorter it is, the more important the morphologic description of the material is. In our problems, involving the securisation of reactive materials, propellant can be submitted to a large spectrum of loading. The first of them is a dynamic loading which leaves the material in a specific state. In this presentation, we show, from microtomography acquisitions before and after tests, the consequences on the sample of different levels of dynamic loading. Numerical simulations are performed at the mesoscale level, and analysis of the loading propagation try to explain the physical events appearing in the sample [2]. Consequences and perspectives in terms of experimental and numerical issues are given.