PKMS machine gun is an automatic weapon functioning on the principle of gas extraction created and produced by the Soviet Union. Based on the prototype of this pistol, Vietnam has developed this gun model. This cannon has great firepower, excellent dependability, compact construction, is simple to operate and maintain, and can be handled on any terrain. This article investigates the simultaneous influence of some structural parameters on the vibration of the PKMS gun (specifically, the barrel's vibration) when fired experimentally as a basis for improving the research ability, contributing to improving the ability to self-design equipment with good features, as well as being able to make good use of this type of equipment to suit the conditions and people of Vietnam.