This system will allow you to sight-in in 5 shots or less. You only need to follow the instructions and be able to shoot a reasonable group. Here's how it works. You aim at a fixed point (target or bulls eye) and carefully fire a 3-5 shot group. You have now established the point of impact versus the point of aim. Now clamp the gun in the vise and use the adjustments on the vise to center the reticle (red dot or crosshairs) on the point of aim (target). Without moving the gun or vise use the adjustments on the sight to move the reticle to the center of the group. You have just mechanically and optically aligned the points of aim and impact, i.e.....you're on target.