Best SCAR 17 ACOG Scope – 3.5X Is Perfect For Medium Range

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Shooting the FN 7.62mm SCAR is super fun, but you have to pick the right SCAR 17 ACOG first.

I went with the Trijicon SDO (Squad Day Optic) 3.5X ACOG for better eye relief and its piggyback Trijicon RMR setup.

The dual optic capability makes the SCAR 17 both close and medium range ready!

Read More: Best Optics For SCAR 17s & 20s


Why Pair SCAR With ACOG Scope?

First of all, never mount any cheap $50 airsoft sight on the SCAR 17 optics. Please buy a heavy-duty rifle optic that will give you the performance and reliability. We see people putting the ELCAN SpecterDR on the rifle, and we have also seen people mounting long-range scope such as the Leupold Mark 5.

FN SCAR 17 With Geissele ACOG Mount

The options are endless, and here we have the best optic for SCAR 17 for medium-range application. The Trijicon SDO ACOG 3.5X magnified sight definitely delivers the performance.  ACOG stands for Advanced Combat Optical Gunsight. Over millions of units sold and used all over the World and no exception for the FN rifles.

If ACOG is not your thing, you can check out other top-rated combat red dot optics.

or please check out the best rifle scope for 308 and other hard-hitting calibers.

Other SCAR 17 Upgrades To Make It Better

One thing we love about the SCAR17s is its look and how it stands out among other guns. After many years of seeing it in video games, movies and in real life, this is maybe the best acog for SCAR 17, but we have to get shoot the heck out of it first.

SCAR 17 Upgrade

The first thing we got rid of is the ugly buttstock that the gun comes with, and then we upgraded the new with the Kinetic Development kits, which include the M-LOK extended rail system, Magpul ACR folding stock(GET RID OF THAT UGLY STOCK WITH THIS NOW), Angled charging handle and Geissele 2-stage Super SCAR trigger. The gun immediately transformed into the most badass gun I have ever seen.

We simply cannot go back to the normal SCAR17s.

SCAR 17 ACOG For Medium Range

The Trijicon SDO ACOG 3.5X is the newest rifle optic for the USMC HK M247 IAR. 3.5X magnification and 1 Trijicon RMR for medium range and close range application. We want to make our SCAR 17s a medium range combat machine.

ACOG 3.5X SDP with RMR

First of all, the size of the ACOG 3.5X with RMR red dot balances out the overall profile of the gun. No one likes to see a huge gun with a small rifle sight on it, and the Trijicon SDO ACOG 3.5X is the best I have seen besides the ELCAN 6X model. The ACOG  SDO has a different front lens profile compared to the regular ACOG 3.5X as well as the 4X version. Its flat front lens allows the use of kill flash, and it’s just a total bad ass look added to the gun.

Choosing the best optic for SCAR 17 is very different for everyone. I configured my SCAR 17s ONLY for medium range and close quarter up from 0 to 200 yards, and the 3.5X is enough magnification.

Trijicon SDO Reticle Is Perfect Up To 200 Yards

The Trijicon ACOG reticle for the SDO is for the 5.56mm, however, up to 200 yards, 308 do just fine. 308 and 5.56mm’s ballistic profile are almost identical within 200 yards. For anything close up we switch to the Trijicon RMR.

scar17 with Trijicon ACOG

Some people will argue that it’s a waste of money and it’s stupid to mount an expensive scope like that for a 7.62 platform gun. I don’t disagree, and I just wanted to have some fun with this. I want to beast this thing out on the range.

If we want to experience 308 for long range, we can take the ACOG off the gun, and put on a Vortex Razor HD precision scope. This is why a quick detach scope mount is awesome, so I can just swap scopes on the go without any tool!

FN SCAR 17 Breaking Optics Explained & Solutions

There are a lot of rumors without any official evidence backing up on how FN SCAR17’s recoil impulse destroys the rifle optics. According to the consumer reports, the SCAR 17’s heavy bolt creates significant forward recoil impulse that damages anything that’s mounted on the rifle such as laser sights, thermal scope, night vision, and high-end rifle sight.

Some argue that the recoil impulse creates a component damaging harmonic waves. It travels across the frame of the upper receiver at a high frequency causing even some of the most durable optics to break. If you want to learn more, please check out this in-depth article here about =>How Recoil Forces Could Affect Scope Accuracy<=

This is what we know from basic physics we learned in high school and college. Certain harmonic wave at its specific wave frequency can destroy structures just like buildings and bridges. When we add damping to the wave is how we stop vibration, and that damping nodes are the scope mount attachment points.

Cantilever Mounts With Recoil Lugs Works The Best For SCAR 17

Geissele Super Precision ACOG Mount Cantilever

The recoil lug under the scope mount is there for a reason. They’re designed to reduce recoil impulse wave. That’s why the industry makes durable components to counter things like this.No wonder scope mounts are freaking expensive…

So get a beefy cantilever mount for all hard recoil rifles including the FN SCAR 17. It will absorb a lot of that recoil wave impulse before the energy is transferred on to the scope.

Here is the solution: Make sure your scope mount is precision made, and make sure you pair a heavy duty scope with a heavy duty scope mount that has high-quality recoil lug to fit in between the rail system and features a tight locking mechanism.  Out of all the options and research I have done the followings are what I recommend.

Best SCAR ACOG Mount For Reliability

The Trijicon SDO ACOG comes with the LaRue Tactical QD lever mount. It’s a great mount, but we want better ones to counter the recoil impulse issue, so we gonna switch it out.

Giessele Super Precision ACOG mount is by far the best cantilever mount I have ever come across. Precision 7075-T6 CNC made with TWO cantilever nuts providing at least 2800 pounds of clamping force. 4 shear recoil lugs maximize rigidity and return to zero. It’s more than enough to keep the SCAR 17 going.

Giessele Super Precision SOPMOD Certified Mounts are approved mounts by USSOCOM, which allows Special Operations personnel to use on FN SCAR MK16 and MK17. The performance and reliability are top-notch when it comes to gears used for USSOCOM. If you choose to run a different sight for the SCAR17, then definitely stick with this mount, click here for the best deal on OpticsPlanet.

Spuhr Cantilever mounts are designed to prevent scope flexing due to heavy recoil. It’s the most expensive and popular for high-end precision shooting application. The best selling points about this mount are that you can add various accessories on to it such as cosine indicator, lasers, and other attachments. It’s the most comprehensive and well-built mount for the price of $450. Check it out to get the BEST DEAL on OpticsPlanet.

The next step is to make sure the mount is torqued to the specified torque value to stay tight on the rifle and to the scope. If your high-quality scope is mounted loose, then it’s going to experience all that G-force during recoil. You can read more on  Gunsmith Torque Wrench here.

The best way to comprehend this concept is to think of a loose engine on an aircraft. The spinning engine blade vibration frequency travels across the rest of the wing.

Therefore the engine must have tightened bolts to ensure that vibration is contained without damaging the rest of the aircraft. In this case for your SCAR 17, your scope will be damaged if it’s not secured properly with the right scope mount.


The Trijicon SDO is an awesome SCAR 17 ACOG. It’s a perfect fit for medium-range shooting. We love it. The 3.5X magnification combined with fast acquisition Trijicon RMR increase the weapon the lethality.

The SDO ACOG will not break due to recoil if you mount it right. Please get a grasp and understand on some basic physics fundamentals, and get high-quality, beefy mount such as Geissele or Spuhr for the Trijicon SDO. Tighten it to the precise torque value recommended for the rifle. The ACOG 3.5X SDO will kick ass and never die on your SCAR17s.