| Firearm is a weapon that uses gunpowder gas as energy and use tube-shaped launchers to fire bullet.Generally,guns with calibers below 20 mm are called small arms which are main weapons of infantry and auxiliary weapons of other combat units.The rifle is a long-barreled firearm operated by infantry.It is mainly used to launch bullets to kill living hostile targets.The effective range is generally 400 meters;bayonet and stock can also be used in close-combat;some can also launch grenades to achieve point-to-face killing objective and anti-armor capability.Rifle is one of basic weapons of modern infantry.Large equipment quantity and wide utilization are its characteristics.The key indexes of firearms are reliability and accuracy which may influence tactical operation and even relate soldiers’ lives on the battlefield.The way how to improve accuracy and achieve better damage effect becomes particularly important.Gas port is drilled in the barrel of the gas-operated weapon.Under pressure,the burning gunpowder gas enters the gas-guide chamber or gas-tube through gas port,and pushes the piston to complete multiple actions such as recoil.The shape of the intersection of the air guide hole and the rifling grooves and lands will directly affect the force of the bullet passing through,and the posture of the bullet will also change when it is launched out of the muzzle,resulting in deviation and affecting accuracy.Therefore,optimizing the position where the air guide hole intersects the rifling groove and lands is an important solution to improve the accuracy.The research includes:(1)Simulation analysis of the influence of gas port position on shooting accuracyIn order to analyze the influence of different topography formed by the circumferential position of gas port and the inner bore on the shooting accuracy,six quadrants were set in Solid Works.The barrels and bullet of the position air holes are simulated in three dimensions,and then imported into ABAQUS for meshing and numerical simulation.The analysis of the influence of the gas port on the bullet velocity,on the barrel bending,on the movement of the projectile,and on the bullet strain are analyzed,It affects the tile velocity and the attitude of the muzzle,thus affecting the firing accuracy.(2)Experimental study on optimization scheme of gas guide holeTrough the combination of gas port optimization scheme experimental study with simulation results and comparative tests according to test data after shooting test by selecting the gas port gun in corresponding to the simulation analysis,analyze the test data,and conduct a comparison test again to obtain the effect of the air hole position on the shooting accuracy.(3)Design and analysis of the process guarantee schemeThanks to the analysis and the combination of the design of process support solution with simulation and test results,the optimized solution for the position of the gas for one type of rifle is determined,and then by analyzing manufacture process feasibility,the feasibility of process control is finalized as well.Three process control schemes are designed,and design analysis is conducted,the optimal process scheme is selected based on which special fixtures and gun body inspection tools are designed.The optimal process schemes is adopted for batch processing and verification tests are done afterwards.After experimental verification,the method for controlling the gas port position is determined,hence enhancing the firing accuracy of certain rifle.To sum up,this paper is mainly carried out from the aspects of simulation analysis,comparative test demonstration,process scheme design and batch experimental research,and the theoretical research and experimental research are carried out at the same time.Through experimental verification,the position control method of air guide hole is determined,and the shooting accuracy of a rifle is improved. |
