To improve the shooting stability of machine guns and firing accuracy， a single rod viscoelastic elastomer damper applied to 12.7 mm heavy machine guns was designed， which was simulated by the variable stiffness Kelvin model. The three important performance parameters （stiffness， damping coefficient， and initial pressure） of the viscoelastic elastomer damper were optimized and matched by orthogonal experiments， and a set of performance optimization parameters best matched the dynamics of the elastomer damper and the anti-aircraft machine gun were obtained. Finally， the dynamic performance of the optimized matching viscoelastic elastomer damper was compared with the spring damper. The results showed that the recoil force of the machine gun using the elastomer damper was smaller， the recoil speed changed more smoothly， and the muzzle fluctuation was smaller than that of the 12.7 mm machine gun equipped with the spring damper.