The first time a low power optic appeared on the sport shooting market, the tactical world took notice. A sighting device that superimposes a reticle on the target would make shooting faster. The quantum leap to low power optics in law enforcement did not take long.
Low power optics are slightly or non-magnified optical devices designed for binocular or occluded vision sighting. This class of optics includes reflex type sights, holographic sights and 1-3x scopes. These products are designed for sighting with both eyes open while one eye looks through the device. For police work, optical sighting devices should be mandatory.
Low power optics generally mount directly to picatinny rails like the EOtech HOLOgraphic sight or use standard scope tube diameters like the Aimpoint Comp Series sights. Their reticles can be dots, suspended crosshairs, triangles or a combination of shapes. The aiming dots are generally larger than 1 MOA (minute of angle) and rarely get larger than 5 MOA, which means they cover about 1 to 5 inches of a target at 100 yards. For most products, the size of the dot cannot be adjusted, although the intensity can. The dots are adjustable for windage and elevation, usually in coarse increments of 1/2 MOA per click.
Low power optics are appropriate for use at any distance one would normally employ a traditional iron sight. Although the shape in the viewing window is almost always bright enough for use in direct sunlight, it is invisible from the muzzle side, even in the dark. Their concept may be simple but the technology behind them, especially the holographic technology, is cutting edge. Once sighted in, anyone can pick up an appropriately equipped firearm and use it. For the officer who goes from gathering information during an investigation to gathering suspects after breaching their entryway, the ability to adjust the stock without having to adjust the sights is enormous.
In combat shooting, several events take place before accurate fire can be commenced. The officer sees the threat, recognizes it and orients. He aligns the sights to the target and responds — whether to fire or hold on target. Succinctly; see target, orient to target, align sights, engage, remove vision from sight alignment to scan.
With iron sights, the shooter sees the target and moves the sights into the field of vision. With low power optics, the shooter keeps the gun in "ready to fire" position and the "bullet will strike here" display stays in his view. There is no loss in peripheral vision. The shooter is no longer scanning over the sights. He is using the sights to scan. Vision and engagement are fused. Succinctly; See target, engage, scan, engage.
Types of sights
Iron sights can only be viewed or accessed from a single ray in space — one that begins from the retina and continues through the rear and front sight. Low power optics can be accessed from a zone that, as long as the retina accesses the image in this zone, the shot is successful. This means the officer can pull the trigger with a less than perfect cheek weld and still deliver aimed fire on the target.
Although using optics has distinct advantages, they are not a cure-all. They are designed to increase the rate of accurate fire, not accuracy. Battery-dependent ones have obvious weak links — capturing an LED or laser image needs batteries to create that dramatic floating image effect.
Optics get dirty. One must clean them with the same care as any other optic. That is, blow them off first, then brush, if blowing doesn't work. Clean them with a more aggressive method only when necessary. Nearly every product has some anti-reflective/maximum transmission coating. Users must take care not to scratch this coating.
One of the advantages of the low power optic is the ability to accept tremendous variances in the eye relief. A sight can be mounted close to the eye or further down the receiver to accommodate for night vision accessories and magnifiers. Most are compatible with night vision and thermal viewers. They may be coupled with a night vision monocular, binoculars or rail-mounted scopes.