Abstract: The action reliability is an important factor which must be considered in the design of mechanisms, and is a key index to evaluate the quality of a system. The main parameters influencing ejection action reliability are determined, and a rigid ejection reliability analysis and design process of automatic rifles is set up. A simplified virtual prototype model of rigid ejection action reliability is established. The simulated results show that the position of ejector, the backplate position of ejection port and the ejection velocity are the dominant factors which have effect on ejection action reliability; as the ejection velocity is high enough, gravity has less effect on ejection action reliability. A method to determine the position of ejector is presented, and the calculational equations are established for location dimension of ejection port. An adjustable backplate of ejection port mechanism is designed to test in the shooting experiment. The experimental results are consistent with the simulated results. It shows that the validity and suitability of the proposed method are verified.Key

Key words: ordnancescienceandtechnology, automaticweapon, actionreliability, reliabilityanalysis, rigidejection