Research on motion match characteristics of a two degree of freedom spring system with impact and momentum offset

In this paper, the motion parameters of a physical prototype which based on a new floating technology with the bidirectional buffer spring is measured. A two degree of freedom floating machine gun model with impact and momentum offset is establishedcal, culated and analyzed. By comparing with the measured results, the correctness of the model is verified. The influence of bidirectional buffer spring and recoil spring stiffness on the motion characteristics, especially the recoil ending state of the floating body, floating efficiency and consistency of firing state are analyzed. The research shows that the stiffness increasing of bidirectional buffer spring accelerates the frequency of the forced recoil-return amplitude attenuated simple harmonic motion of the floating body, and lags the phase of the bolt carrier group relative to the floating body at the firing time; increasing the stiffness of the recoil spring increases the motion frequency of the bolt carrier group, and advances the phase of the bolt carrier group relative to the floating body at the firing time, which both have an influence on recoil ending state of the floating body, the floating efficiency and the consistency of the firing state. Keywords: Momentum offset; Two degree of freedom system; Floating technology; Machine gun system