In order to make sandy shrapnel be used in gun exterior ballistical test, the difference of a certain type of shrapnel's characteristic quantity before and after retrofit was statistically analyzed. The concept of characteristic dispersion was put forward, with dynamic balance angle, the exterior ballistics theory was applied to analyze polar rotational inertia of bullet and centroid position affecting the projectile dispersion, and the range of shrapnel's characteristic quantity satisfying flight stability was calculated. The shrapnel's characteristic quantity pre-and post retrofit was studied applying to the projectile dispersion. By means of analysis and calculation, it is found that sandy shrapnel based on the process level would produce severe projectile dispersion, and there is no excuse to make the sandy shrapnel be used in gun exterior ballistical test.