Adding a red-dot reflex sight to a carry pistol has pros and cons. First, the cons. The total cost of the weapon system nearly doubles as the sights are almost as expensive as the pistol, the sights have a larger footprint than the typical rear sight, battery life must be monitored, and foul weather can diminish the capability of the sight. The pros are the sights offer faster target acquisition and ease of aiming. The ability to shoot faster and more accurately in situations under 25 yards are strong reasons to make the switch from iron sights to a reflex sight, so we wanted to investigate mounting a reflex sight on a pistol to see how a reflex sight would work on a carry gun. We chose a Glock 20 Gen 4 as our test platform for two reasons. Glocks are popular pistols among LE and civilians and because the G20 is chambered in 10mm, which has comparable power to a 41 Magnum. We wanted to rattle the innards of these tiny sights to see if anything would fall out, get loose, or go out of zero. Even though the G20 is a full-size pistol, we have found that with the proper holster, like those from Bravo Concealment, and a concealing garment, the G20 can be invisible to the untrained eye.
A reflex sight allows an operator to keep both eyes open and view a target through a small curved glass lens, which has a reticle projected onto it. A light-emitting diode projects a red dot, amber chevron, or other aiming point, giving the operator an unlimited field of view since there is no magnification and the aiming point projects out to infinity. This means that parallax will not affect sighting; place the aiming point on a target, and if zeroed properly, the target will be hit.
Think of them as mini heads-up displays for your pistol.