Hysteresis properties and viscosity effects have been studied at several temperatures (in the range from 140 to 500K) on hard Sm(Co,Cu) 5 alloys. The application of a recently proposed theoretical approach permits one to identify the fluctuation field H f , connected to a typical activation volume, and the Preisach distribution, connected to microstructure. We found that: (i) at a single temperature, the model is able to reproduce the complex magnetization dynamics measured under pulsed field history excitation in a detailed fashion; (ii) the Preisach distribution for different temperatures can be rescaled onto a temperature-independent single curve through a temperature-dependent scale factor H A (T) equivalent to the anisotropy field.