The present invention relates to a gun tube having a spin curve with a variable spin angle as well as a rifling force R(x) over the path of the projectile (x) through the gun tube when a projectile is fired, as well as a predetermined caliber d, projectile mass m.sub.G, mass moment of inertia J about the longitudinal axis of the projectile, gas pressure force P(x) on the projectile bottom and projectile velocity v(x). In order to realize, within the framework of manufacturing tolerances, an accurate spin curve corresponding to diverse desired characteristics of the rifling force, it is provided that the rifling force R(x) is determined according toR(x)=R.sub.max R.sub.n (x)where R.sub.max is the maximum rifling force value which is a function of a predetermined final spin angle .beta..sub.E and R.sub.n (x) is a predetermined, standardized rifling force curve with a defined onset of spinning, a defined initial spin angle and a defined spin profile, with the development of the spin on the caliber diameter being determined from the following differential equation: ##EQU1## and from R.sub.max for a given final spin angle .beta..sub.E.