In this paper the analysis of the sources of errors occurrence of measuring tool of the speed of the thrown element in the bore was carried out. The connection between the characteristics of the constituent elements of the error and influence quantities was established. The formulas for the components of the error of measuring tool were obtained for each of the sources. The generalized mathematical model of instrumental error was proposed, the interval estimate of the boundaries of its valid values was presented.
relative error, mathematical model, small arms, measuring tool, speed