displayed some mass can be removed from the side 12 or circumference of a projectile 11 or a projectile can be formed with mass already removed such an absence of mass from a side 12 can leave a recess 13 the absence of mass from a side of a projectile will cause the center of gravity of a projectile to be in a different location than the central axis of the projectile the center of mass can also be shifted a distance from the central axis of the projectile by adding mass to the side of the main body the more mass taken from the circumference of the projectile will result in the projectile striking the target further from a bulls eye however the more mass removed the more vibration there will be during flight the vibration is due to the obp projectile spinning around the center of mass and not the central axis of the projectile while the magnitude of this vibration is relatively low 0 005 inches for a 30 caliber bullet that strikes the target 10 inches from the bullseye at 100 yds maximum turns in the rifling would reduce the amount of mass that had to be removed from the projectile the removal of mass can leave a recess in the side of the projectile the recess can be located either ahead of or underneath the cartridge case the recess may be filled with epoxy or some other material to create a smooth surface to aid aerodynamic flow through the air the material can have a density that is less than the density of the.