Investigation of the effect of manufacturing parameters on the residual stress and accuracy distribution in rifle barrels manufactured by the button rifling

In this research, the effects of manufacturing parameters on residual stress distribution and accuracy performance were experimentally investigated in rifle barrels manufactured using the button rifling method. The study was conducted using barrels produced with six different sets of parameters, where the cutting speed (23–30 m/min), feed rate (0,08–0,10 mm/rev), and button pull speed (762–1270 mm/min) applied during the reaming process were systematically varied. The effects of these variables on internal barrel surface roughness (Ra), residual stress distribution determined via XRD, and shot grouping (MOA) measured at a distance of 105 meters were analyzed. According to the results, barrels processed with a feed rate of 0,09 mm/rev exhibited the best accuracy performance, achieving an average surface roughness of Ra = 0,7 µm and an average shot grouping of 1,073 MOA. Similarly, barrels produced with a moderate cutting speed (27 m/min) showed high performance with a grouping average of approximately MOA ≈ 1,371. In contrast, the barrel subjected to a high button pull speed (1270 mm/min) exhibited increased subsurface tensile residual stresses and a rise in MOA value from 1,162 to 1,206. Notably, barrels with lower residual stress levels in the 0° direction provided more stable shot groupings, with an average of 20% lower MOA. These findings demonstrate a strong correlation between the orientation of residual stresses induced during manufacturing and shooting accuracy. This study contributes significantly to the literature by establishing an experimental basis for the process–parameter–performance relationship in rifled barrel manufacturing and provides direct technical guidance for the defense industry in producing high-precision, domestically manufactured firearms.