Abstract: To study the firing stability of a new large calibre machine gun in different ground environment, the stability model of arms rack and dynamic model of the whole gun were established respectively. The stability condition in clunch and concrete environment was educed, and the force in shoulder which was required for the stability of machine gun was also calculated. Then a dynamic model of this gun at one firing movement was established. Based on this and dynamic simulation software, the muzzle displacement response in different ground environment was obtained. Comparing the simulation result and contrasting with one older machine gun, the well favorable adjustability and firing stability are proved strongly, which is the firm theory and practice foundation for stability argumentation and improving of new large calibre machine gun.

Key words: new large calibre machine gun, firing stability, ground environment, muzzle response, dynamic simulation