Given the variety of MSRs out there, it should not come as a surprise that there are multiple options when it comes to sighting systems. At one end of the spectrum is the traditional, basic M16-style iron sight; at the other end are variable-power riflescopes with high upper-end levels of magnification. All have their place.
Most AR-type rifles today come with a Picatinny rail on the upper. Makers do that because they correctly assume that the owner will likely want to put some type of optic on it. That wasn’t always the case.
Not so long ago, the default sights on MSRs were aperture-style iron sights. Don’t overlook the utility of traditional irons: With a protected front post and two different-size peeps that the shooter can toggle between—a larger peep for more rapid target acquisition and close-in shooting, and a smaller, finer peep for precise shots at longer ranges—these sights are nearly indestructible and, with a bit of training, very effective.
A standard 3-9x40mm variable power scope can accomplish a lot of tasks. But the best scopes for everything but extreme-range shooting are 1-6X optics or, if you can afford them, scopes with a 1-8X magnification range. These will handle everything from targets at powder-burn distances to those out to 500 yards.
Many scope manufacturers make reticles with holdover and windage marks that are calibrated for ARs. These reticles are most commonly etched to match the trajectory of a 55-grain bullet travelling at 3,100 fps, though reticles for other popular .223 loads are also offered. I have shot a number of these scopes and they work very well.
The best reticles are those that have clean designs where the holdover marks are easy to distinguish from each other, so that the shooter doesn’t need to count down from the center to figure out which mark is the right one for a distant target.
Non-magnifying optics offer a lot of configurations. In general, these sights are an improvement over iron sights because of their ability to function well in low light and, in some cases, because they have holdover marks for engaging targets at longer distances.
1. Reflex Sights
Reflex sights project an aiming dot back to the shooter’s eye. The design eliminates the effect of parallax and offers unlimited eye relief. They are lightweight but can be somewhat fragile unless encased in a protective chassis. Battery life for these is usually measured in years, as the amount of power it takes to illuminate the dot is less than what the battery loses when actually disconnected.
2. Holographic Sights
Larger and beefier than reflex sights, holographic optics project a bright reticle back to the shooter. The intensity of the reticle can be dialed up and down based on the shooter’s requirements.
The hardened design is meant to withstand the rigors of combat. They can be combined with magnifiers that swing into place for longer shots.
3. Fiber Optics
By gathering ambient light in order to illuminate the aiming point, fiber optics eliminate the need for batteries. Some manufacturers offer these sights in conjunction with glowing tritium and battery-powered aiming points to offer the best of all worlds. (Fiber optics designs are also found in fixed- and variable-power scopes as well.)
4. 1X Optics
1X optics are scopes that do not magnify and have large, bold reticles. The simplicity of their design makes them especially rugged.