Research of the method and instrument of measuring the velocity of a projectile in a barrel of a firearm

The information about the dependence of the powder pressure or the velocity of the projectile in the barrel in a function of time (the so-called ballistic elements of the shot) plays an important role for specialists in the design, modernization and assessment of the state of small arms and ammunition. Known methods and instruments of measuring the powder pressure in the barrel when firing include irreversible destruction of the sample of a weapon, and the common methods and related instruments of measuring the velocity of projectiles are well adapted to take measurements only outside the barrel. One of the promising ways to increase the accuracy of determining the ballistic elements of a shot is to measure the instantaneous values of the velocity of the projectile during the initial periods of the shot, in particular, inside the barrel. The paper describes the principles of construction of the instruments of measuring the instantaneous velocity values of the projectile on the basis of the double differential method of laser Doppler anemometry. The order and peculiarities of transformation of measuring information are considered, the algorithm of its processing is given. The sources of errors of the instruments of measuring are analyzed, the expressions for the components of the error are obtained, their quantitative evaluation is performed. The description of the experimental unit for the study of the instruments of measuring is presented, the results of the experimental researches on the modelling of the process of shooting and registration and processing of the measuring information are given. The presence of a stable measuring signal and the possibility of its registration and processing in the conditions of measurements close to real are practically confirmed. The results of the studies can become the basis for the creation of a prototype of the instruments of measuring the velocity of the projectile in the barrel.