Method of Measuring the Ballistic Coefficient of Bullets

The method, employing universal expressions, was examined to determine the ballistic coefficient of a bullet by the G7 standard (air drag law for the flight of a long boat tail tangent ogive G7 bullet in view of its muzzle velocity and flight trajectory descent within a 100–200-m range). The method permits of measuring the ballistic coefficient of a bullet without a specialized measuring laboratory, i.e., under unequipped shooting-ground conditions. The only metrological equipment is a mobile unit for evaluating the muzzle velocity. The relation is derived based on the experimental design by the central alternate that describes the range of point values for an examined process since the range of nonexistent ones does not permit of employing the uniform alternate. The range of initial bullet velocities is divided into the three subranges to include all points of the central alternate into the range of existent values. The above ballistic coefficient-based approach can be used to compute the bullet velocity at an arbitrary distance in the tests of armored targets under field conditions without bulky equipment. The reliability of describing the examined process is provided by the approved mathematical model of the bullet flight in air as the motion of a solid body based on the system of four differential equations of first order. Adequacy of empirical description of the relation between the ballistic coefficient and muzzle velocity and flight trajectory descent within 100–200 m is verified by determining the standard deviation for the values based on the mathematical model of the bullet flight and the polynomial and their comparison with the accuracy of the ballistic coefficient measurement (no more than 10^-3).