Digital ballistic computer for the fire guidance system of a tubular weapon which calculates, based on given firing data from firing tables, the ballistic data of the projectile path, composed of a digital memory unit storing data constituting discrete firing table values for each type of ammunition intended for use in the tubular weapon, the stored data corresponding directly to data contained in firing tables, and an approximation computer connected to access the memory unit, and to receive inputted firing data and operative for determining ballistic data, from the stored data and the inputted data, by approximation operations.