The durability, versatility and speed built into iron sights, the earliest solution developed for accurately aiming a gun, has not faded with time. Advancements in design have magnified those virtues, along with modern materials, leaving little doubt that you need iron sights on your AR if you’re serious about shooting.
Don’t make the mistake of dismissing them as an obsolete relic of the past. Whether you own a modern sporting rifle for home defense, weekend matches, plinking, hunting or a combination thereof, there’s a version ideally suited for your pursuit.
They don’t garner headlines like the latest-and-greatest magnified optic, but iron sights keep you in the fight, at the firing line, or afield on opening day if your primary optic or its batteries go down. Some are also fully capable of delivering accurate shots at incredible distance by practiced hands. Others are designed for fast target acquisition up close and a distinguished few that do both with ease.
An iron sight consists of two separate components- front and rear. They are non-magnified and there is no glass surface for viewing. No activation is required and there’s no worrying about unexpected battery death, because there are none.
The unit that goes forwardmost (front sight) on a rifle or carbine is usually a post or bead, most often black, but some wear a white or a color dot, even luminescent, to enhance target acquisition. Some have the added protection of barriers on their sides.
The rear sight can be a V or U-shaped notch, often with index marks to reflect estimated windage holds. It can also be a cylindrical-shaped peep sight. The best of those versions feature more than one aperture (diameter of their hole), which allows owners to set up the system for targets up close, fast, and simply rotate when something at distance requires precision.
The term “iron” is a misnomer today. Modern versions are constructed from weight-saving and rugged aircraft-grade aluminum or alloy steel. Both materials make the sights a long-lasting investment that will survive the kind of harsh conditions that often render optics inoperable or abuse bases and rings until they surrender. The acronym BUIS, which stands for backup iron sights, is applied as a label on many of those designed for AR-15s and AR-10s.
There are some polymer models on the market today, but their quality varies. Shop at Bear Creek Arsenal to ensure value and quality.
Regardless of design, the front unit (front sight) of any iron sight anchors as far forward as possible on the firearm, where it does not interfere with critical components or fire controls. Most attach directly to the fore-end’s Picatinny rail and take only a few seconds to mount on a firearm.
The rear sight goes as far back on the receiver as the owner finds comfortable. The ideal position allows them to acquire a sight picture fast and effortlessly without altering cheek weld or gun position. That’s usually all the way back on the receiver (rear sight) if the unit is mounted on top of the receiver’s rail. Shooters and results vary, so trying different positions is always a good idea.
If you have an optic already mounted on a modern sporting rifle there might not be real estate available for the iron sights on top. Even if there is room views can get obscured and performance compromised. There are a few solutions, but the most elegant is an offset BUIS. They are home-defense and match-grade awesome.
They also mount on the rails of an AR-15, but are built with an angled base to keep them out of a primary optic’s field of view. Most shooters prefer them to ride on their trigger-finger side of the gun.
The advantages are noteworthy. If there’s not enough time to activate the red dot sight or the targets are so close it’s impossible to find them in the field of view in time, an offset BUIS sight picture is lighting fast with only a slight rotation of the gun. It becomes lifesavingly intuitive with practice. The difference they make shows during action shooting sports matches, particularly on stages with a mix of nearby targets and others at distances long enough to make a scope advantageous. Competitors simply transition between sighting systems, which makes a magnified optic atop with offset iron sights a solution employed by dozens of top shooters.
The separation between the front and rear sight should always be maximized, regardless of the iron sight’s design. Fire control and accessory positions may dictate a compromise, but the further apart, the better. That distance is calledsight radiusand it plays a critical role in the ability to deliver a precision shot, whether with a long gun or pistol.
Windage, Elevation and Aperture
Quality iron sights today are rock solid and reliable, like most of their predecessors, but they add another facet. They have the ability to adjust for windage as well as elevation with a precision and repeatability that was scarce in early models.
Years ago those solidly anchored beads or posts up front on a bolt-action rifle were fixed, unmovable and sometimes hard to see. Some models could handle elevation changes at the rear sight, but it was usually rudimentary, at best. Kentucky windage is no longer part of the equation with today’s best BUIS sights, thanks to modern CNC machining.
Those notches on the rear unit of some iron sights fulfill their mission with style, but their primary purpose isn’t drilling deep into sub-MOA territory. That’s where those cylindrically shaped peep sights shine, offering different hole diameters to enhance sight picture. Their basic design isn’t really new, although the today’s ability to quickly and easily change aperture on the fly is a feature ideally suited for ARs. Simply rotate to tiny and precise when you’re at the range testing your load and skill. Then change to the wider diameter and the gun’s set up for home defense.
All the virtues make it obvious today’s iron sights don’t deserve second-tier status. They are fast, versatile, rugged and accurate. For those reasons they serve as the primary system, instead of high-powered scopes, on thousands of ARs today.
There’s another advantage, too. Many fold down or (flip up sight) when needed, without losing point of aim, for ease of transportation or storage. If they are indeed serving a backup role, the ability to go flush against the gun until needed maintains that “low drag” profile needed for “high speed.” With a simple push of a button they release and you’re ready to engage that target. This "adjustable" quality makes them a must have.
Using Iron Sights and How To Aim
Regardless of the iron sight version you select, the basics are identical when it comes to their use. It boils down to simple geometry and the degree-angles.
In its most rudimentary form, you look downrange through or over the rear sight—properly in the peep or while concentrating on the lowermost spot in a notch until the target is centered and steady in your aimpoint. At that point you’ve formed a straight and imaginary line between your eye and where you want the bullet to impact.
Next, move the barrel slowly until the front post or bead intersects that line and is directly in front of the target. Now, gently lower or raise that post until you reach the manufacturer-recommended sight picture (while maintain the proper view through the rear sight).
It sounds grade school simple, but there are dozens of variables, including how steady your rest is and consistency of your cheek weld/eye placement. Things are also wide open in iron sights when compared to the view through a high-powered scope, so some wander is a common malady at first. Remember, though, that generous field of view has a decided advantage in self-defense and competition, where finding and transitioning from one target to the next is much faster.
Then there’s the challenge of always placing that dot or post in the same spot. It’s tempting to completely obscure the bullseye or leave a large gap between it and the post. The latter will force you into painful guesstimates that increase in complexity with distance. In some exclusively self-defense or CQB models the former may be the proper sight, but it minimizes precision at long distance.
It’s simple, but takes time at the range to build the kind of consistency that breeds confidence. Bear in mind, too, every shooter is different. If something reliably and repeatedly works for you, even if it’s a slight departure from most recommendations, think twice before accepting the advice of armchair quarterbacks.
There isn't a shortage of reasons you need iron sights on your AR. They’re simple, adjustable, reliable, rugged and a great back-up. With practice you’ll be surprised at the groups you print at surprising distances.
Once that’s accomplished, then it’s time to explore that front post diameter and it’s often overlooked ability to serve as a rudimentary ranging device. Unlike a laser rangefinder, it doesn’t need batteries, either. We’ll leave that geometry lesson for another day.
To learn more about Rifle optics be sure to check out our youtube video.