Numerical investigation of dynamic buckling and elastic-plastic deformation of an aluminum straight round pipe under axial compression conducted using finite element method and explicit time integration scheme implemented in Abaqus commercial code. The problem set-up is based on descriptions of an experiment available in literature. Elasticity and plasticity with isotropic hardening models are applied for the material simulation. Finite element model containing 304k nodes and 244k continuum first order reduced integration elements created for the case. Influence of small initial geometric shape imperfections on post-buckling pipe deformed shape and resistance force vs impactor displacement dependency is studied. Simulation results are compared with corresponding experimental data. A conclusion is drawn that post-buckling pipe deformed shape is dramatically influenced by existing initial shape imperfections and consequently has a probabilistic nature. In contrast, spike values of resistance force during formation of the two first folds depending on the considered initial imperfections varies only 4–8%. During formation of the third fold the variation increases to 33%. Total impactor displacement value variation is 8%.