An accuracy of numerical prediction of buckling load of axially or locally loaded thin-walled circular shells was always been a challenge for engineers. With the introduction of new materials and manufacturing methods, well known design rules can be too conservative in the case of buckling performance. New advanced or more sophisticated analyses/design methods should be considered to fully utilize buckling load capacity of modern structural design. The major factors which can affect numerical prediction of buckling load are combination of initial geometrical imperfections and shell imperfection sensitivity. Shells having high imperfection to wall thickness ratio a/t are most affected, in contrast thicker shells are less sensitive. The current study deals with less sensitive shell, subjected to combined axial/bending loading introduced by three support posts which acts locally introducing local skin buckling. Prediction accuracy obtained by employing detailed finite element modeling of real case boundary conditions and interaction of involved components. Combination of shell elements with 3D solid elements and utilization of contact algorithm for sliding spherical ball supports produce highly reliable buckling load experimental and numerical prediction.