Erosion analysis of machine gun barrel and lifespan prediction under typical shooting conditions

Abstract

The operational lifespan of a conventional weapon, such as artillery or machine gun, highly depends on the performance of its barrel. The bore of a machine gun is exposed to erosion as the number of rounds fired increases, which results in continuous increases in barrel diameter and thus an undesired degradation in ballistic performance. In this study, a critical isothermal erosion model for a machine gun barrel is established, and a numerical simulation method is used to study the bore erosion under typical shooting conditions. The current study confirms the presence of thermal-chemical erosion as a predominant failure mechanism at the starting point of the barrel rifling. It is also noted that this thermal-chemical erosion zone expands with the increase in the number of shots fired. Increases in firing frequency, and ambient temperature, and a decrease in the interval between cartridges are found to aggravate the erosion of the barrel bore. By fitting the calculated results, a formula for predicting the maximum erosion at the starting point of the barrel rifling is constructed. The predicted results demonstrate acceptable deviations from the experimental ones, which verify the accuracy and feasibility of the newly developed method in predicting machine gun barrel lifespan.