If I understand your question correctly... Yes, you will have different measurements for different bullets. The reason is that a comparator measures close to, but not exactly at the ogive of the bullet where it would contact the rifling. Since you are measuring at a different place on the bullet, then the steepness of the angle of the nose of the bullet will affect how far the distance from the measuring point to the actual ogive is, which can then give different measurements for different bullets.