为探讨步枪系统发射过程中的准确物理参数，以牛顿第二定律和内弹道学计算公式为理论基础，建立其动力学数学模型.利用该模型计算了内弹道时期和后效期全枪系统的后坐力、后坐位移、后坐速度、角速度和角位移，以及枪机组件的运动位移和速度.计算结果表明，最大后坐速度和最大后坐力均发生在枪弹飞离枪口时，最大后坐位移发生在火药气体作用的后效期.该方法为步枪系统发射动力学的理论研究及其数学建模探索了一条新路径，对同类系统发射动力学特性的进一步分析探讨具有参考价值.

In order to gain the accurate physical parameters of rifle system during shooting process, dynamic mathematic model of rifle system was established based on Newton second laws and the internal ballistic formula. The model was employed to calculate the recoil forces, displacements, velocity, angular velocity and angular displacements of the whole rifle system as well as displacements and velocity of bolt carrier. The calculating results indicate that both the maximal recoil velocity and the maximal recoil force emerge while bullet flying off gun muzzle, and the maximal recoil displacement takes place at the action aftereffect period of explosive gas. The method offers a new means for theoretical study of shooting dynamics of rifle system and its mathematic modelling, and it is worth reference while carrying the further analysis of shooting dynamic characteristics of systems of the same kind.