3 Best Scope for FN SCAR 20S

There’s no doubt the FN SCAR 20S is a long-range superstar. Top this short-stroke gas piston semi-auto with the right optic, and you can use it to drive tacks in targets at 800 yards. 

Not sure what optic to mount on your SCAR 20S? We’re here to help. We’ve put in the research and fieldwork to bring you three of the best scopes for FN SCAR 20S rifles available to modern shooters.  

These optics are not only worthy of the rifle’s precision prowess, but they are also sturdy enough to take the abuse SCARs are known to dish out on their scopes. 

What is the Difference Between SCAR 17S and 20S?

Barrel length is the main difference between these two semi-auto rifles. The SCAR 20S has a 20-inch barrel, while the 17S has a 16.25-inch barrel. The longer barrel of the 20S keeps the bullet supersonic longer, which adds in-flight stability beyond 800 yards. 

FN designed the SCAR 20S for long-range precision shooting, and that’s where this rifle really shines. 

What Caliber is the FN SCAR 20S?

FN offers the SCAR 20S chambered in 7.62x51mm (basically the NATO version of .308 Winchester) and 6.5 Creedmoor. Both cartridges have serious long-range potential, especially when paired with a high-quality scope.

The 3 Best Scopes for FN SCAR 20S

Here are three of our favorite optical partners for the hard-hitting and highly accurate SCAR 20S.

1. NightForce ATACR 4-16×42 – Editor’s Pick

When it comes to long-range precision shooting, the NightForce ATACR sets the bar, and that bar is incredibly high. 

Magnification and Parallax Adjustment

The NightForce ATACR’s 4-16x magnification range works well for the SCAR 20S’s effective range. It even has an integrated power throw lever for instant magnification changes, which is a handy feature when engaging multiple targets at various ranges. 

The ATACR has a side knob that adjusts for parallax from 45 yards to infinity. NightForce chose to mark the parallax adjustment with approximate numbered distances. 

Glass Clarity

The ATACR features fully multicoated ED glass lenses that are hand-aligned. The sight picture on this scope practically knocked our socks off. With insane brilliance and razor-sharp clarity, the ATACR makes other scopes look pale in comparison. 

Reticle

NightForce offers the ATACR in a wide range of illuminated first focal plane reticles. There are smart options in both MOA and MRAD configurations. 

Our favorite is the MOAR F1. This is a relatively simple long-range reticle. It features elevation and windage markings that allow for accurate on-the-fly ranging and hold-offs. The MOAR also has a floating center crosshair that makes it easy to get on target fast.

Durability

The ATACR’s main tube is machined from solid 6061-T6 aircraft-grade aluminum alloy bar stock. The walls are more than twice as thick as the walls of most other scopes, so this optic is built like a tank.

The ATACR is also nitrogen purged and o-ring sealed. It is reliably shockproof, fogproof, and waterproof. 

This one is built for the battlefield, and it is tough enough to withstand rough treatment, as well as some of the harshest landscapes on Earth. 

Turrets

The ATACR has a 34mm main tube and an internal adjustment range of 89 MOA in elevation and 60 MOA of windage. The turrets are capped to prevent accidental adjustments in the field. 

NightForce also has what we believe is the best Zero Stop feature in the industry. Dubbed ZeroHold technology, this feature offers an instant return to zero. It also lets you dial below zero, which is incredibly valuable when engaging close-range targets. 

Mounting and Rings

Using the NightForce 34mm ring set to mount the NightForce ATACR should really be a no-brainer. 

Is It Worth It?

We get it. This scope comes with a pretty hefty price tag. You’ll be lucky to find one for under $2500. 

But before you faint from sticker shock, we want to remind you that in the world of riflescopes, you get what you pay for. 

“Buy once, cry once,” is our motto. The initial investment is going to sting a little, but we swear this optic is worth every single penny.

The ATACR has everything you would expect a high-end, long-range precision optic to have, plus a few extras. 

Features

• Illuminated FFP reticle.
• Fully multi-coated ED glass.
• Side parallax adjustment. 
• Power throw lever. 
• ZeroHold technology.

Summary

The US Marine Corps uses the NightForce ATACR (which stands for Advanced Tactical Riflescope) for their Mk13 Mod 7 sniper rifle system. 

Enough said. 

Pros

• Durable, low-profile design. 
• Illuminated FFP reticle.
• Impeccable image clarity. 
• Generous FOV. 
• Battle-proven performance. 

Cons

• Expensive.

2. Trijicon ACOG 6×48 – Best Fixed Power Prism Scope

Putting a battle-proven optic like the Trijicon ACOG (Advanced Combat Optical Gunsight) on the battle-proven SCAR just makes sense. 

Magnification and Parallax Adjustment

The 6x magnification may not seem like enough for you to take advantage of the SCAR 20S’s effective range. However, military snipers have historically used fixed magnification scopes, many of which offered little more than 6x magnification.  

Using a lower magnification, fixed-power scope also makes it easier to track moving targets much easier. 

Because the ACOG is a fixed power scope, there’s no need to adjust for parallax. 

Glass Clarity

Trijicon uses multi-coated lenses to enhance light transmission. This optic has a sharp, clear field of view with no noticeable distortions. 

Reticle

The Trijicon ACOG is famous for its battery-free illuminated reticle. The illumination is powered by fiber optics for reliable daytime illumination. It then turns to a tritium phosphor lamp for reticle visibility after the sun goes down.  

The illumination level self-regulates to match ambient lighting conditions, which some shooters find handy. (It’s us. We’re some shooters.)

The 6×48 is also the only ACOG model that offers a manual brightness adjustment override.  

We mostly love that the illumination is always on and ready to go. There’s no power switch to worry about, and the batteries never die (because there are no batteries). 

The ACOG has several simple reticle designs to choose from, including chevron, horseshoe, triangle, donut, and basic crosshairs. Most feature bullet drop compensation (BDC) marks for precision aiming at distance. 

Durability

This tough optic was engineered for battle. In fact, no other magnified optic has seen more combat action than the Trijicon ACOG.

Built from sturdy aircraft-grade aluminum, the ACOG is filled with dry nitrogen and o-ring sealed to eliminate internal fogging. 

The optic exceeds military waterproof standards and is submersible to 500 feet. It is also tested to perform reliably in extreme temperatures. 

Honestly, there’s nothing you can dish out that this optic can’t handle. 

Turrets

The ACOG’s turrets are simple, functional, and robust. When adjusting windage and elevation, the finger-adjustable knobs provide highly tactile and audible clicks. 

Mounting and Rings

The ACOG comes with a Picatinny M1913 rail adapter. The optic itself also has an M1913 rail so you can easily attach extra accessories. 

Is It Worth It?

If you want a nearly indestructible optic, you won’t find anything sturdier than the Trijicon ACOG. 

Pairing a SCAR with an ACOG just makes sense, especially if you want to use a DMR (designated marksman rifle) setup. 

Features:

• Bomb-proof construction.
• Waterproof, shockproof, and fogproof. 
• Generous eye box. 
• Multi-coated lenses.
• Battery-free illuminated reticle. 
• Finger-adjustable turrets. 

Summary

US Special Forces helped Trijicon design the ultimate combat optic. The ACOG is the result of that collaboration. 

Today, the US Army uses the Trijicon ACOG 4×32 as their field carry optic. Trijicon took the same concept and increased magnification for the ACOG 6×42 to “enhance target identification and increase hit probability on extended-range shots”

Pros

• Always-on illumination. 
• No batteries to change. 
• Practically indestructible. 

Cons

• Fixed magnification may limit versatility.

3. Leupold Mark 3HD 6-18×50 – Best Budget Scope for SCAR 20S

Because the SCAR 20S is designed for long-range precision, you really need a top-notch optic to get the most out of the rifle. 

In a perfect world, everyone would have an unlimited optics budget. Unfortunately, we do not live in a perfect world. 

However, the Leupold Mark 3HD does strike a near-perfect balance of affordability and performance. 

Magnification and Parallax Adjustment

The Leupold Mark 3HD has an ergonomic power selector, which allowed us to quickly and easily change magnifications in the field. 

The scope also has a convenient side focus knob for parallax adjustment. 

Glass Clarity

The Mark HD3 features premium, fully multi-coated HD lenses. Leupold also uses their exclusive Elite Optical System, which is engineered to enhance light transmission and reduce glare. The result is nice low-light brightness and clarity. 

Reticle

One of the things we love most about this scope is its illuminated FireDot reticle. This thing has seven brightness settings to maximize visibility in almost any lighting condition and against almost any backdrop. This allows you to line up with the target super fast. 

We could even easily see the reticle in harsh sunlight, which is no easy feat. 

Durability

Leupold ensures the Mark 3HD can withstand anything you or Mother Nature can dish out. The company puts its scopes through “The Punisher,” which is Leupold’s exclusive impact testing system. The Punisher delivers pretty violent abuse, so you can rest assured that this is one solid optic. 

The Mark 3HD is also filled with nitrogen and o-ring sealed, making it reliably fogproof, even in the wettest shooting conditions. 

Turrets

For long-range shooting, we really appreciate a scope with a solid zero stop function, and the Mark 3HD has one. It creates a stable backstop to prevent turning the dial a full revolution in the wrong direction. 

Mounting and Rings

We highly recommend using Leupold’s 177094 Mark AR integral Mounting System to attach the Mark 3HD to your SCAR. This mounting system provides extra contact with your rail for a precise, rock-solid fit.

Is It Worth It?

Because the SCAR 20S is designed for long-range precision, we really want to top it with a Leupold Mark 5 3.5-18×44. However, we understand that some shooters might not be able to slap down that much cash, especially right after dropping several thousand dollars on a SCAR.

If you’re on a tight budget, but still want a quality optic, the Leupold Mark 3HD 6-18×50 is a smart option. We aren’t sure how Leupold keeps this model under $1000, but we’re thankful they do. 

Features:

• Waterproof, fogproof, shockproof. 
• Reliable zero stop feature. 
• Side focus parallax adjustment. 
• Easy-grip power selector. 
• Illuminated FireDot reticle. 
• Fully multi-coated HD lenses. 
• Elite Optical System for superb low-light performance. 
• Lifetime warranty. 

Summary

The Leupold Mark 3HD has everything long-range shooters want, plus it has an affordable price tag. Because this scope is jam-packed with high-performance features, we hesitate to label it a “budget” scope. But we still wish it was the Mark 5. 

Pros

• Affordable price tag. 
• Lightweight design.
• Durable construction.
• Illuminated FireDot reticle with seven brightness settings. 
• Respectable low-light clarity. 

Cons

While there isn’t technically anything wrong with this scope, it just doesn’t offer the same level of clarity and durability as the Mark 5. Once you’ve used the Leupold Mark 5, it’s hard to settle. 

Conclusion

Finding the best scope for FN SCAR 20S largely depends on your budget. If you want serious long-range capabilities, you’ll need to make a serious investment. 

Our favorite optic for the FN SCAR 20S is the NightForce ATACR 4-16×42. This quality optic is designed for precision long-range shooting, just like the SCAR 20S. It will help you milk every ounce of long-range accuracy possible from your rifle.

If you want a battle-proven scope, the Trijicon ACOG 6×48 makes a classic partner for the SCAR 20S.

For budget-conscious shooters, the Leupold Mark 3HD 6-18×50 is a practical option that won’t abuse your bank account.