There are tons of scopes on the market and it can be tough to know which is the best optic to put on top of your AR.
Lucky for you, you have this guide to help you out. We’ll talk about what exactly makes a rifle scope good for using on an AR-15, the different types of AR-15 scopes, and how to choose an AR-15 scope. All of that will give you the context you need for the last section, our list of the best scope for AR-15s.
Riflescopes have a few advantages over other optical systems.
They have the same unobstructed sight picture as a red dot or holographic sights, in contrast with iron sights that must partially block the target. However, scopes also have built-in magnification.
The average AR-15 chambered in .223/5.56 NATO (the standard ammo for this carbine rifle) has an effective range of between 400 and 600 meters (between about 435 and 655 yards). That limited range means that most AR-15 scopes have relatively low magnification. Many even have a magnification range starting at 1x, meaning no magnification at all.
This low magnification is great for close quarters (CQB), short, and medium-distance shooting. Since .223 isn’t really a long-distance round, higher magnification isn’t necessary. Though AR-15s chambered for certain other calibers may be used for long-range shooting, AR-15 scopes are typically designed with .223/5.56 in mind.
In fact, some AR-15 scopes actually have reticles designed specifically for this round. They have hash marks precisely located to indicate the necessary holdover at different distances based on .223’s ballistics for spot-on aim and fast, easy target acquisition. These are a type of BDC (bullet drop compensation) reticle, but there are also universal BDC reticles.
Universal BDC reticles have hash marks that indicate a particular number of MOAs or mils. They allow you to use your knowledge of your round’s ballistics to determine which mark represents the right amount of bullet drop at what distance. They’re trickier to use, but can be used with different rounds.
Most AR-15 scopes use a BDC reticle, whether universal or designed for a particular round. However, you can also find AR-15 scopes with crosshair or duplex reticles, particularly scopes for close range and CQB.
AR-15 scopes fall into one of two different categories: fixed or variable magnification scopes.
Fixed magnification scopes have a single magnification strength that can’t be changed. Variable magnification scopes, on the other hand, have movable lenses that allow you to choose your magnification strength within a particular range.
That gives variable magnification scopes more versatility, but the moving parts mean they’re also more expensive and less durable than fixed magnification scopes.
Fixed magnification AR-15 scopes are often prism scopes.
Unlike traditional scopes, which use lenses to focus the image, prism or prismatic scopes have a glass prism to do the same job. This allows prism scopes to be more compact than traditional rifle scopes, so they’re great for the AR-15 and other modern sporting rifles. They tend to have low magnification.
AR-15 scope reticles are typically in the second focal plane (SFP). That means the reticle is located behind the magnification lens, so the reticle is not magnified by the lens. Because it’s not magnified, the reticle stays the same size no matter what magnification power setting is used.
A first focal plane (FFP) scope has the reticle positioned in front of the magnification lens. Because of that, the reticle appears to change size as the magnification strength is changed, just like everything else in the sight picture.
What Do You Look For In The Best AR-15 Scopes?
When trying to select a high-quality scope for your AR-15, there are a few things you’ll want to be sure to keep in mind:
Whether you opt to go with a fixed or variable magnification scope, you want to choose one with the right magnification strength for your needs. The longer the distance and the smaller the target, the higher the magnification you need.
For example, for home defense and other close-quarters situations, you’ll want a scope with a minimum of 1x magnification. A maximum magnification of between 4 and 6x on the same scope will give you more options for property defense, as well as for short-range recreational shooting.
On the other hand, for medium to long (for the AR-15, anyway) range varmint hunting, you’ll want something more powerful. Depending on the precise range and target size, a minimum magnification between 3 and 6x should do the trick. You’ll want to pair that with a maximum magnification of at least 9 to 12x, again, depending on the range and target size.
As for fixed magnification scopes, a 3x or 4x prismatic scope will cover you for most of the AR-15’s range. You could go a bit lower if you’ll be shooting primarily at the lower end of the rifle’s range, or higher if you’ll be mostly taking longer shots.
Scopes can go through a lot, so it’s important that they’re able to stand up to whatever is thrown at them.
Look for a scope that is well-constructed and made from durable materials. Materials like polymer and aircraft-grade aluminum balance durability and weight. Ensure that the scope is also shockproof, waterproof, and fog proof so that it can stand up to drops and moisture.
A good sight picture is one of the most fundamental qualities that any scope should have.
To achieve a good sight picture, a scope should have multi-coated lenses made from high-quality glass. Lens coatings help filter light to improve contrast, color fidelity, and image clarity.
And speaking of light, light transmission is also very important for the sight picture. The more light transmission, the clearer, and brighter the picture, and the better the scope performs in low light.
Lens coatings play an important role in ensuring that not just plenty of light, but also the right light, is transmitted. However, so does the diameter of the objective lens. The larger the objective lens, the more light it’s able to collect.
However, scopes still need a decent amount of ambient light to give you a clear picture. For hunting in the dark, you’ll need to go with a true night vision or thermal scope.
Best AR-15 Scopes Reviewed
Bushnell 1-4X24 AR Optics Riflescope (Our Top Pick)
Our top pick is the Bushnell AR Optics Riflescope, a close-range scope with 1-4x magnification.
It has the Bushnell Drop Zone-223 BDC reticle, which is designed for .223 ammo and has held up to 600 yards. The exposed windage and elevation turrets allow for easy zeroing. There’s also a throw down power control lever with two height options.
This Bushnell scope is IPX7 waterproof and fog proof and comes with the Bushnell Lifetime Ironclad Warranty.
Fully multi-coated lenses
Easy to use
Wide field of view
Turrets are non-locking
Can be difficult to mount with low rings
Relatively bulky compared to the other scopes here
It’s highly durable with UTG’s True Strength Platform and nitrogen purging, making the scope fog proof, rainproof, and shockproof. The universal mil-dot reticle features red/green dual illumination for excellent visibility in low light conditions. The emerald coated lenses help with sight picture quality.
At 8.11 inches long and 13.9 ounces, this scope is compact, especially for its magnification. That, coupled with the long eye relief (4.2 to 3.2 inches), makes it comfortable to shoot.
Comes with 2” sunshade, flip-open lens caps, and QD rings
¼ MOA zero resettable and zero lockable target turrets
An adjustable objective allows for 3 yards to infinity parallax adjustment
Magnification is high for CQB and short-range
The reticle is not designed specifically for .223/5.56
Trijicon ACOG scopes have an excellent reputation, one that they earned through use in military combat.
This particular ACOG features a red chevron BDC reticle with holds optimized for .223/5.56 NATO. The reticle has tritium/fiber optics illumination for battery-free illumination that automatically adjusts to surrounding light conditions. It also has a matte black finish and a thumbscrew mount.
However, there are other versions with different magnifications and combinations of features that are also well suited for an AR-15.
All ACOGs have rugged forged aluminum housing and fixed power design for durability. They’re waterproof and shock-resistant.
The Vortex Optics Spitfire is a prism scope, a design that allows it to measure just 5.5 inches long and weigh 15.4 ounces.
This compact scope has a custom BDC reticle optimized for 5.56 withholds for up to 500 yards. This glass-etched illuminated reticle can be used with either red or green illumination, or with no illumination at all for traditional shooting.
On a single CR2032 battery, the scope can get up to 250 hours of battery life on the highest brightness setting and up to 3,000 hours on the lowest.
Primary Arms SLx 1-6×24mm SFP Rifle Scope Gen III – Illuminated ACSS-5.56/5.45/.308
The Primary Arms SLx has PA’s famous Advanced Combined Sighting System (ACSS) reticle, optimized for 5.56/5.45/.308.
This reticle has hash marks to help with both elevation and windage adjustments, so it’s great for tracking moving targets. It allows for quick target acquisition up to 300 yards and is accurate up to 800 yards. The reticle is illuminated for low light visibility.
This durable scope is nitrogen purged and made from 6063 aluminum, so it’s waterproof, fog resistant, and won’t corrode. It comes with the Primary Arms Lifetime Warranty.