An approach to the analysis of the magnetic levitation of the projecti
le in the coilgun's interior trajectory is proposed. The magnetic forc
e acting upon the armature has the nature of a restoring force but its
profile changes in every instant. So the transverse movement of the p
rojectile can not be described by an ordinary oscillation caused by a
restoring force. Since. the transit process is calculated numerically
step by step and all the necessary data are obtained at each step the
analysis of the levitation motion can be implemented in the same way c
onveniently. The character of the magnetic forces acting upon the arma
ture is analyzed in detail. The computation of the magnetic levilation
during the whole transit process of a 5-stage gun is presented.