Velocity decrease of bullets in ballistic tests

In this study, the form factors and ballistics coefficients of the fragment, weighing 1,1 grams fired at the Afyonkarahisar Ballistics Laboratory located at an altitude of 1020 meters were determined, by taking into consideration the friction coefficient in the indoor environment, and the velocity decrease calculation of the particle was made. The 1,1 gram fragment used in the velocity measurement experiment is the shrapnel of the 105 mm howitzer bullet and is fired from the 7.62 mm G3 barrel. Measurement in the experiment were made with the Oehler 35P choronograph. In the experiment, 4 sensors were used and the sensors were positioned at a distance of 2100 mm, 1000 mm, 860 mm and 610 mm from the barrel, respectively. Aramid plate was used as test plate during the experiment. This velocity decrease calculation has been applied to the V50 speed test within the scope of TS 13349, MIL-STD-662 F and STANAG 2920 standarts, and the result of velocity losses obtained both experimentally and theoretically has been reported. The results of experimental measurements conducted at different speeds and with varying amounts of gunpowder were compared with theoretical results, and the error margins between them were determined. As a result of the measurements, speed losses of up to 4% were detected at low speeds (550-560 m/s), while speed losses decreased to 3% at high speeds (650-660 m/s).