The collapse of empty square aluminium columns is examined using dynamic nonlinear elasto-plastic finite element analysis. Different finite element models are considered and attention is paid to the effect of boundary and initial conditions. Specifically, symmetry boundary conditions, which are associated with quarter- and half-column modelling, are compared with the full-column model. The work employs the LS-DYNA explicit finite element solver and considers generic geometries that are typically used in industrial applications. Three aspects of the work are accordingly examined. The first considers the influence of initial, symmetry and boundary conditions upon the mode of collapse. The second examines the influence of the introduction of foam on the mode of collapse, and the third focuses on numerical anomalies that are typically not accounted for in the literature and the dramatic role they play in dictating the mode of collapse.