In the rifled barrels of each type of armament, the material wear of the rifled bore is closely related to the number of fires shot, this being expressed by the variation of the inner diameter of the barrel in the sections where the measurements were made and evidenced by the decreases in the initial velocity, (ΔVo) relative to the number of fires shot (N). As the number of fires shot increases, the initial velocity of the fired projectiles decreases. In the present paper, the regression equation of the initial velocity of the 76 mm, 1982 model cannon was determined and it was emphasized that the differences between the initial velocity determined by the regression calculation (Voir) and the experimentally determined initial velocity (Voi) are very small. Therefore, it can be appreciated that the law of regression of the determined initial velocity reproduces faithfully the real situation of the decrease in the initial velocity when firing with this type of cannon