This study quantifies the contribution of variant projectile velocity at a gun muzzle to its dispersion at an aim point from an analytical approach. The dispersion was formulated on the basis of stochastic physical conditions including potential crosswind effect. As a result, the statistical quantities of projectile impact distribution could be obtained from the stochastic formulation. In addition, this research proposes correction factors that may be needed when comparing dispersion in angular mil at multiple downrange distances. The significance of the correction factors was demonstrated through a few application examples.