Red dot sights use refractive or reflective optics to generate a collimated image of a luminous or reflective reticle.This collimated image appears to be projected out to a point at infinity, which makes the image of the reticle appear to the user to be projected onto the target. Due to the fact that
the reticle image is collimated, magnifying the image of the target is impractical, as it would make the sight too hard to hold steady. The collimated image does have its advantages, however, as the scope can be placed at any distance from the
eye without distorting the image of the target or reticle. This makes red dot sights suitable for use on pistols, submachine guns,
 rifles, or shotguns.