The 4 Best Ruger AR 556 Scope [2021 Update]

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Not sure what scope to get for your ruger AR 556?

Look no further.

I’ve tested ALL the best ruger AR 556 scope (plus ruger AR 556 scope mounts and accessories.)

By the end of this guide, you’ll find the perfect optic for your ruger AR 556.

Let’s get started!

The 4 Best Ruger AR 556 Scope

If you’re pressed on time, here’s a quick list of the best scopes for ruger AR 556:

  1. Vortex Strike Eagle 1-8×24: Best Overall
  2. Bushnell Drop Zone 1-4×24: Best For The Budget
  3. Trijicon ACOG 4X32: Best Ruger AR 556 ACOG
  4. Sig Sauer Romeo5: Best Ruger AR 556 Red Dot Sight

1. Vortex Strike Eagle 1-8×24: Best Overall

The Vortex Strike Eagle 1-8×24 is the best overall optic.

In fact:

I’m making this bold claim because I’ve done everything from short-range to long-range target shooting with only this one scope.

Here’s how:


Glass Clarity & Reticle

The Strike Eagle has crystal-clear, high-quality glass for half the price.

The fully multi-coated lens is a premium feature. It optimizes the transmission of light for a brighter image, all while reducing reflection so you don’t give yourself away.

Vortex Strike Eagle glass lens

A reticle can make or break an optic and the AR-BDC3 absolutely makes it. It has several cool features I want to touch on.

First, the center dot and the surrounding halo promote instinctive target acquisition and fast execution while providing holdover and ranging references from 0-600 yards.

Vortex Strike Eagle reticle

Secondly, and more technical, the reticle’s BDC is calibrated to the 556 cartridges coming out of an AR-15 or Ruger AR 556, making this scope your AR’s new best friend.

The second focal plane scale of the reticle maintains the reticle’s size throughout all magnifications so the reticle remains readable no matter the distance.

Finally, the glass-etched reticle is protected between two layers of glass for optimum durability and ensures that the optic remains usable even without the illumination turned on.

Overall, the reticle is very easy to use, accurate, and full of useful information without being distracting.

At this price point, something had to give and that’s the illumination feature for me. Despite 11 levels of illumination, it’s still not daylight bright.

That being said, the reticle is still visible in most daylight conditions due to the glass-etched design and I’ve been able to shoot despite it.


Eye Relief & Eye Box

The Strike Eagle has a 3.5” eye relief which allows for both eyes open shooting.

Vortex Strike Eagle Eyepiece Eye relief

This space is much shorter when the scope is maxed out at 8x so be sure to practice good cheek weld and wear eye protection for long range shots.


Durability

I’ve yet to be disappointed with Vortex’s quality and this scope once again checks all of the durability boxes.

Overall, the Strike Eagle has a rugged construction that’s waterproof, shockproof, fogproof, and ready for whatever you throw at it- or throw it at.

First, it’s fully waterproof and designed to meet IPX7 standards. The single-piece tube ensures its waterproofness while also enhancing your base optics.

Vortex Strike Eagle Waterproof

The scope’s Nitrogen gas purged body means that the scope is fog-free no matter the temperatures or fluctuations. You’ll have a clear shot no matter the weather.

I barely had to adjust my stance after mounting the Strike Eagle thanks to its lightweight. At only 17.6 oz, this optic is incredibly light and built for speed.

Scopes have to endure a lot when paired with a rifle. The Strike Eagle is prepared to take a beating thanks to the ArmorTek coating and aircraft-grade aluminum construction.

Plus, the lifetime warranty is great for my peace of mind.


Elevation & Windage Knobs

Both the elevation and windage knobs are a standard 140 MOA adjustment with smooth, audible clicks.

Vortex Strike Eagle Windage and elevation

I’m a big fan of its covered adjustment turrets which prevent me from accidentally knocking it out of alignment.

Right out of the box, I was able to zero quickly and it’s had no problem holding through my usage.


Parallax & Magnification

The wide range of magnification from 1-8x makes this a versatile scope good for short-, mid-, and long-range shooting.

Vortex Strike Eagle magnification

It’s very close to true 1x, but there is a slight fish-eye if you’re in a small room. Once you get further out, 20 ft or so, it’s a true 1x.

The optics get dark at 8x; it’s still a very shootable image but worth mentioning.

Vortex Strike Eagle magnification and parralax

The included thread-in throw lever is a great addition that makes target acquisition faster and easier.

As for parallax, the scope is fixed at 100 yds. While it’s not parallax free, no scope is, it does a great job of managing parallax through all magnifications.


Mounting & Rings

No mounts or rings are included, but 30mm rings are easy to find and the mount depends on your weapon.

For my AR-15, I use the Aero Precision Ultralight 30mm mount to capitalize on the scope’s lightweight design for a truly agile setup.

Aero Precision Ultralight 30mm Scope Mount, Standard, Anodized Black
  • 6061 T6 extruded aluminum construction
  • MIL-A-Type 3 black hard-coat anodize
  • Ridged and lightweight

Vortex does include both ocular and objective flip-up caps which are a great addition to improve the longevity of the scope’s life.

Vortex Strike Eagle Scope with caps

A CR2032 battery powers the illumination and comes in the box. It also has a compartment for a spare battery so you can always be prepared.

Vortex Strike Eagle Battery

Is the Vortex Strike Eagle 1-8×24 worth it?

The magnification range on this optic makes it incredibly versatile.

Short-, mid-, and long-range shots are all attainable with one scope, making it a great aid for hunting, tactical, or target shooting.

Here’s why it works:

  • Fully multi-coated lenses
  • Waterproof, fog proof, and shockproof
  • Vortex Lifetime Unconditional Warranty
  • Glass-etched, second focal plane AR-BDC3 reticle

In short, this scope has all of the fine details of a premium optic at a fraction of the price.

If you’re wondering whether the Vortex Strike Eagle 1-8×24 is right for you, I say, try it and see for yourself.


2. Bushnell Drop Zone 1-4×24: Best For The Budget

If you’re anything like me, then you’re always looking for the best deal.

I don’t believe in paying an arm and a leg for a scope that’s not worth it. So when I find one that’s a great value and has tons of features I’m thrilled.

The Bushnell Drop Zone 1-4×24 is that scope.

For the price, you would be hard pressed to find a scope this durable and reliable.

It’s perfect for close or medium range, and it’s performed well at an indoor range and outside on my AR.

Keep reading and I’ll tell you why you need this scope.


Glass Clarity & Reticle

The glass is crystal clear and the etched reticle makes it great for low-light shooting.

It’s got a fully multi-coated optic lens and I was able to clearly and accurately track my target at 500 yards.

The drop zone reticle makes targeting a breeze. The aiming points every 100 yards make it so you never miss your shot.

Bushnell Drop Zone Reticle

If you’re trying to shoot in full daylight though, this scope is gonna leave you wanting. It excels in low-light, but it’s hard to see the reticle in full brightness.

Since I usually use this for early morning or dusk varmint hunting, it’s met and exceeded my expectations.

This is my favorite scope for short range shooting. At 100 yards the glass is so clear it’s like you’re standing next to your target.

With that kind of clarity the wild hogs on my property don’t stand a chance.


Eye Relief & Eye Box

It’s got a solid eye relief of 3.5”.

Bushnell Drop Zone Eye focus ring and magnification ring

It fit perfectly on my AR-15 and gave me a generous eye box. I never felt cramped.

Some people are gonna want more eye relief, but for me it was adequate.


Durability

This scope is rustproof, nearly scratchproof, waterproof, and fogproof.

It’s got O-rings that keep it sealed and keep out any moisture that could get in it. If anything manages to get past those, the nitrogen purging system eliminates it.

Bushnell Drop Zone Mounted

I’ve taken this scope everywhere with me and it holds up to all the abuse I’ve thrown at it.

I knocked it against a tree while hiking through the woods, and dunked it in a river that was deeper than I thought. It still worked perfectly.

The anodized aluminium alloy it’s made of makes it heavier than some other scopes at 18oz, but it’s worth it for the added durability.

Whether you’re hunting on your property, in the woods, or up in the mountains, this scope has you covered.


Elevation & Windage Knobs

The turrets click audibly when adjusted and they turn easily.

All the turrets are exposed, but they’re built securely. I was concerned they would accidentally adjust if bumped, but I was pleasantly surprised to never have that issue.

Bushnell Drop Zone Windage

It took me less than five minutes to zero it and it’s held zero for over 4 mags now.

If I do have to adjust it, the turrets are marked so I know exactly where my zero was. It eliminates the guesswork you sometimes get with adjustments.

One of my favorite features is the throw down PCL lever. It makes it so easy to change your magnification on the fly.

It’ll let you flip from short range to medium range like that and it does so without knocking your settings out of whack.

It was really handy for me when I was sitting in a bluff to be able to quickly change my magnification like that.


Parallax & Magnification

It’s mag is 1-4x with an objective lens of 24mm.

It’s not going to do you any favors if you’re going for long range shooting.

Bushnell Drop Zone Eye Magnification

At 100 to 500 yards though, it’s perfect.

The 1x isn’t true, but it’s close enough that I could keep both eyes open without straining. I’ve had other scopes that cost a lot more that couldn’t guarantee that.

I didn’t experience any issues with parallax, but it’s got an easy side adjustment turret if you need it.


Mounting & Rings

It doesn’t come with any mounts or rings, so you’ll need to buy those. You’ll need 30mm rings for it.

For the price, that wasn’t a deal breaker for me.

I use an Aero Precision Mount for mine and it doesn’t budge. It’s a little pricier, but completely worth it.

Aero Precision Ultralight 30mm Scope Mount, Standard, Anodized Black
  • 6061 T6 extruded aluminum construction
  • MIL-A-Type 3 black hard-coat anodize
  • Ridged and lightweight

It comes with a lens cover and honestly, that’s about all you need for this scope to do its job.

Bushnell Drop Zone covered scope

Is the Bushnell Drop Zone 1-4×24 worth it?

For the price, absolutely. Sure, you could get a better scope with more features, but if you’re on a budget, then this scope is amazing.

To recap, it’s got:

  • 1-4x mag
  • 3.5” eye relief
  • Crystal clear clarity
  • Great for low-light shooting
  • Waterproof, fogproof, rust-proof
  • Anodized aluminium makes it super durable
  • Throw down PCL lever makes mag changes almost instant

If that’s not enough, it also comes with the Bushnell’s lifetime warranty. No matter what happens to it, they’ve got you covered.

What have you got to lose? Go check out the Bushnell Drop Zone 1-4×24 for yourself.

Bushnell Optics, Drop Zone Reticle Riflescope with Target Turrets, Matte Black, 1-4x/24mm
  • 30 millimeter tube dia
  • Drop zone reticle; Field of view (feet at 100 yard) 90 feet at 1X to 23 feet at 4X
  • Fully multicoated optics

3. Trijicon ACOG 4X32: Best Ruger AR 556 ACOG

If you’re looking for an ACOG (Advanced Combat Optical Gunsight) for your Ruger AR 556, the Trijicon ACOG is what you need.

It is a top pick for most military and law enforcement officers.

If you don’t trust them to pick the best option, read on to find out what makes the Trijicon ACOG the best choice.


Glass Clarity & Reticle

With the Trijicon ACOG you’ll get a crisp, clear image.

When I bought this optic, I wasn’t expecting such crystal clear glass, so it was a nice surprise.

Trijicon ACOG Glass

The anti-reflective coating is an added bonus, that cuts down on glare and prevents distortion.

What about the reticle?

It’s a dual illuminated, red chevron made specifically for the 556.

Trijicon ACOG Reticle

What that means is that it’s perfectly calibrated for 5.56 rifles and it’s a ranging reticle. It compensates for bullet drop out to 850 yards.

On top of that, you’ll never have to worry about running out of batteries like you would with any other ACOG. That’s because it’s a tritium/fiber optic reticle which will adjust the illumination for you based on the lighting condition.

While it’s not a thermal scope, I found that I was able to make low light shots accurately with this illuminated reticle.


Eye Relief & Eye Box

With the Bindon Aiming Concept (BAC), the Trijicon ACOG promotes using both eyes open.

Not only does this give you a wide field of vision, you’ve got the use of all your peripheral vision. So you’ll have the full situational awareness necessary for combat or self defense.

Trijicon ACOG Scope

The one downside to this optic is the eye relief. It’s only 1.5 inches, making it a little tight.

However, I found that with enough training I was able to manage it and eventually get used to it.


Durability

When you’re looking for the best scope for the Ruger AR 556, you’ll want to know you’re getting something that lasts.

The Trijicon ACOG is made from aircraft quality aluminum that is nearly indestructible.

It’s fogproof, shockproof, waterproof, and tested to withstand harsh conditions.

Trijicon ACOG Top view

I took mine to a 2 day tactical course and it held up well through the dust and the heat of the desert.

Trijicon also offers a limited lifetime warranty, so they’ll take care of it if you have any problems.


Elevation & Windage Knobs

The elevation and windage turrets are 2 clicks per 1” at 100 yards

They are external and easy to adjust with just a finger click, no tools necessary.

Trijicon ACOG Turret

What about zeroing?

I had mine zeroed quickly and easily and, after hundreds of rounds, it’s still holding.


Parallax & Magnification

The magnification is fixed at 4x.

This gives you a great view at intermediate to short ranges, making it optimal for the Ruger 556 maximum effective range.

This optic has greatly improved my accuracy at 500 yards because the 4x zoom allows me to easily see my target.

For long range shots, you’ll need something with a little more power, like the Athlon Optics Argos BTR GEN2, but the Trijicon ACOG is very precise for 50-500 yards.

One small issue I have with this optic is that it’s not parallax free, like it’s described. Or at least, I did find some parallax moving my head side to side. A good cheek weld solves that problem though, and it is parallax free moving up and down.


Mounting & Rings

Another reason this optic is perfect for the Ruger 556 is that it comes with a flattop mount that makes attaching it easy.

Trijicon ACOG Mounts

You also get a neoprene scope cover with it.

It doesn’t have a lens cover though, so I bought a Trijicon flip-cap cover for extra protection.

Sale
Trijicon AC11030 ACOG Flip Cap Eyepiece for 4x32mm Models Black
  • Package length: 3.555 cm
  • Package width: 6.858 cm
  • Package height: 13.716 cm

Is the Trijicon ACOG 4×32 worth it?

The Trijicon ACOG will increase your accuracy and give you the confidence you need to make your shots with the Ruger 556.

It features:

  • Clear glass
  • 4x fixed magnification
  • Battery free illumination
  • Chevron red, ranging reticle
  • BAC for high situational awareness
  • Dual illumination that adjust automatically

If you want to join the professionals and get the best scope for your Ruger 556, try the Trijicon ACOG 4×32. You’ll be happy with the results.

Trijicon ACOG 4 X 32 Scope Dual Illuminated Chevron .223 Ballistic Reticle, Red
  • BATTERY-FREE ILLUMINATION: Features a tritium/fiber optic illuminated reticle that automatically adjusts the brightness based on available light
  • RUGGED ALUMINUM-ALLOY HOUSING: Forged 7075-T6 aircraft-aluminum-alloy housing provides for a nearly indestructible sighting system
  • “BOTH EYES OPEN” DESIGN: The ACOG can be used as a CQB sight when shooting “both eyes open,” utilizing the Bindon Aiming Concept. The ranging reticle is calibrated for 5.56(.223 cal) flattop...

4. Sig Sauer Romeo5: Best Ruger AR 556 Red Dot Sight

When it comes to red dot sights, there are a lot of choices out there.

You could spend all day looking at products and reading reviews.

But I’m here to tell you that this is the last red dot sight review you’ll ever need to read again.

That’s because the Sig Sauer Romeo5 is the absolute best red dot sight for any tactical rifle platform, like the Ruger AR 556.

Read on to find out why.


Glass Clarity & Reticle

For starters, the glass on the Romeo5 is exceptionally clear.

Some red dot sights have a colored tint due to their coatings, but this is not the case with this optic. This is because Sig Sauer multi-coated the lenses of this scope with their Spectracoat lens coating to eliminate glare without reducing light transmission.

Romeo 5 Glass

Color fidelity is nearly perfect, which means I can clearly and easily acquire and identify my target before taking any action.

Now, a little about the reticle.

The Romeo5 uses a 2 MOA illuminated reddot reticle.

Romeo 5 red dot

I think 2 MOA is the perfect size for a red dot reticle. It provides a great balance between precision and visibility. The reticle is large enough to be easily seen, even by aging eyes like mine, but not so large that it obscures my target at longer ranges.

I have noticed the slightest bit of blurriness with the reticle at times, but this is a problem with me and not the scope. I have astigmatism, so I get that distortion with every illuminated reticle I use.

However, the 2 MOA size means that even when the dot blurs and distorts, the reticle doesn’t hide my target.

This optic also provides ten different brightness settings. The lowest two are compatible with night vision.

Even without night vision, the lower settings are perfect for low-light or night shooting. I’ve found that a 2 at night and a 5 during the day are the perfect brightness settings for my eyes.


Eye Relief & Parallax

Here’s the best thing about red dot sights: Unlimited eye relief.

The Romeo5 is no exception to this rule. You don’t even have to worry about staying in a rigid eyebox.

Romeo 5 Scope

This means that you can shoot from unconventional positions with ease. Even if the dot isn’t in the center of the scope, if you can see it and put it on target, you’ll make your shot every time.

Plus, like all red dots, the Romeo5 is completely parallax free.


Durability

For it’s small size and low weight, this optic is incredibly durable.

It’s waterproof to a depth of one meter, fogproof in all weather conditions, and shockproof to handle recoil and drops.

Romeo 5 Waterproof

And if that wasn’t enough, Sig Sauer tested the Romeo5 at operating temperatures from -40 to 140 degrees, so you can take it to any corner of the globe and not worry about any problems with the electronics or the glass.

It’s waterproof to a depth of one meter, fogproof in all weather conditions, and shockproof to handle recoil and drops. And if that wasn’t enough, Sig Sauer tested the Romeo5 at operating temperatures from -40 to 140 degrees, so you can take it to any corner of the globe and not worry about any problems with the electronics or the glass.

A big part of what makes the scope so durable is its single-piece design. The whole tube is crafted from a single piece of aircraft grade aluminum, so it’s both lightweight and tough as nails.

Plus, the whole thing only weighs 5.1 ounces, which means more comfort for the shooter.


Elevation & Windage Knobs

The turrets on this optic work well enough, but aren’t my favorites.

They are not hand adjustable, so you have to use the key that comes with the scope or some other small screwdriver to make adjustments. And when making adjustments, I could feel the clicks, but only barely.

Romeo 5 Windage

They are not hand adjustable, so you have to use the key that comes with the scope or some other small screwdriver to make adjustments. And when making adjustments, I could feel the clicks, but only barely.

That said, this scope adjusts 1 MOA per click which is plenty precise for close to mid range shooting. I was able to set the scope up for cowitness, so when I went to zero my Ruger AR, I was on bullseye in three shots.

Since mounting and zeroing, I’ve put about 700 rounds through my Ruger with this sight on it and the zero has held. So, the lack of hand adjustability isn’t really an issue, since I haven’t ever needed to make any adjustments.


Battery

The Romeo5 uses a single CR2032 battery to power the red dot.

But here’s my favorite thing about this red dot: the MOTAC automatic activation system.

This optic uses a motion detector to sense when you bring your rifle up to shoot and automatically powers on the red dot when you need it. Even better, it shuts it off when you’re done because it stops sensing movement for a few minutes.

This means that just one CR2032 battery will last you for more than 40,000 hours. That’s an insane amount of battery life! I’ve had this scope for months and have never needed to change the battery.


Mounting & Accessories

The Romeo5 includes a built-in Picatinny rail interface for easy mounting to almost any weapon platform. It also includes both Low and 1.41 inch Cowitness risers.

I personally love running my red dots cowitness, so I used the 1.41” riser to mount this to my Ruger AR. Mounting was quick and easy, thanks to the included tool.

The mounting tool is also the same key used to make adjustments on the turrets. It’s nice to only have one tool to keep up with for this optic.

The Romeo5 also includes a nice bikini-style lens cover to protect your scope from dust and scratches while not in use.

If you want to add some magnification to your rifle platform, I highly recommend getting the Holosun HM3x Flip Magnifier. It matches perfectly with the Romeo5 and gives you optional 3x magnification to extend your range even further.

Sale
HOLOSUN HM3X 3X Flip to Side Magnifier,Black
  • Flip to the Side design.
  • Compatible with Absolute and Lower 1/3 Height Optics.
  • QD Mount and Spacer Included.

Is the Sig Sauer Romeo5 worth it?

All in all, the Sig Sauer Romeo5 is an incredible red dot sight in a lightweight package.

It’s got:

  • Clear glass
  • Low weight
  • 2 MOA red dot reticle
  • 10 brightness settings
  • Durable, single-tube design
  • Automatically powers on and off
  • Includes mount, risers, and lens cover

And if all that wasn’t enough, the Romeo5 is protected under Sig Sauer’s INFINITE Warranty, so you know you’re covered for life if anything happens to your optic.

So if you’re looking for a quality red dot sight for your AR or AK platform, look no further than the Sig Sauer Romeo5 Red Dot Sight.


Now It’s Your Turn

I hope you enjoyed my best ruger AR 556 scope guide.

Now I want to turn it over to you:

Which rifle scope will you pick for your ruger AR 556?

Let me know by leaving a quick comment down below.

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