FN SCAR 20S: Out-Of-The-Box Precision

FN SCAR 20S: Out-Of-The-Box Precision
The gas system has two settings: “normal” and “suppressed.”
The gas system has two settings: “normal” and “suppressed.”
The gas system has two settings: “normal” and “suppressed.”

Over-engineered and made battle tough, the FN SCAR 20S offers a superb trigger and great accuracy, as well as a lot of fun.

What Makes The FN SCAR 20S So Accurate:

  • A Geissele Super SCAR two-stage trigger breaks like thin ice.
  • Stock is fully adjustable to fit the user.
  • 11-pound weight makes it somewhat milder mannered.
  • Cold hammer-forged barrel is chrome lined, making it stress-free barrel, accurate and wear-resistant.
  • Short-stroke piston operation is extremely reliable.

Back in the earlier years of the 21st century (geez, I’m referring to the 21st century! That still isn’t old), FN designed a set of rifles for the military. The military wanted it all—the sun, moon, stars … and a decaf, no-calorie latte.

The SCAR rifle series ended up being the SCAR-L (for a while, the SCAR 16) and the SCAR-H (for a while, the SCAR 17). The L/16 was an indestructible 5.56 rifle, but it was a bit chunky and heavy for 5.56. The other was an indestructible 7.62 NATO that was, well, a bit chunky and heavy, but not for a 7.62.

At the time, I predicted the end result, and time has proven me right: If you let the end users (the SOCOM heavy-hitters) pick and choose, they’d rather have the 7.62 than an indestructible 5.56.

Mile-Long Top Rail

FN didn’t stop there, so we now have the SCAR as a 7.62 precision rifle. The 17 is still there, but this is the 20S, a rifle built to be a long-range precision rifle … OK, a sniper rifle.


And, to that end, FN didn’t leave anything to chance, as far as making it suitable for long-range precision use was concerned. The stock is adjustable in both length of pull and cheek height. The trigger is a two-stage trigger, with a pull weight that’s factory-set between 3½ and 4½ pounds.

The upper receiver (which is the firearm on the SCAR, unlike the various AR-15 and AR-10 rifles most readers are familiar with) has a top rail that runs the full length of the receiver.

Bone Up On FN Guns:

Weight Considerations

This provides plenty of “rail estate” (and yes, I did invent that term almost two decades ago) to mount optics, iron sights, and thermal and night vision optics. Now, the bare weight of the SCAR 20S is 11½ pounds. Ouch! Adding a full suite of optics can probably push that up close to 20 pounds. And, add on a bipod, laser targeting designator, suppressor, full magazine and a sling, and you’re up to the weight of some of the lighter belt-fed machine guns.

There’s also a rail at the 6 o’clock position on the handguard; so, you could, if you owned one, mount a grenade launcher there. The rest of us will simply use it as a generous length of rail to which we can attach a bipod.

Disassembly is easy: Push one pin across and then take the rest of it apart with your bare hands.
Disassembly is easy: Push one pin across and then take the rest of it apart with your bare hands.

For most of us, this is a heavy rifle. But, for the end users for whom the rifle is built (those hard, fit, 20-somethings who can do pushups until they’re tired of counting), this isn’t a problem.

But—and this especially in the 6.5 Creedmoor chambering—with the 20S you have pinpoint precision out as far as you can hit … or as far as the caliber reaches before the bullet goes subsonic. And, if I might be permitted an aside here: While the 7.62 NATO, with pretty much any loading, will go subsonic at a bit past 1,000 yards at most, the best loads of the 6.5 Creedmoor stay supersonic out to 1,600 yards, even 1,700, depending on atmospheric conditions.

More About the SCAR 20S

OK, back to the 20S details.

The gas system is a short-stroke piston setup, and the original users wanted reliability. To that end, FN made the working parts robust and ensured dimensional stability (that is, everything is made to very tight specs, even when there are generous tolerances for crud to blow out).

If the reciprocating charging handle is a problem, you can easily swap it out for an angled one from HDD Tactical.
If the reciprocating charging handle is a problem, you can easily swap it out for an angled one from HDD Tactical.

One detail I’ve heard about from those who’ve used their SCAR rifles hard is that the rifles are hard on optics. This is mostly the 7.62 crowd—the SCAR 17 users. The 17’s generous gas throttle, along with its robust cycling parts, means that on every shot, the operating system bottoms out in the rear of the receiver … with enthusiasm.

Now, for the shooter, that’s not a big deal. The SCAR is reasonably comfortable to shoot, and the stock, either standard or the 20S, is adjustable, so you can set it up to fit you. A side note here: The SCAR 17—the L—has a folding stock that’s adjustable for length of pull and cheek height. The 20S has adjustable length of pull and cheek height, but it doesn’t fold.
The recoil-and-bounce cycle of vibration acts not unlike that of some air rifles. The double-hit and vibration can rattle apart lesser scopes, so you should really make sure you use top-notch scope brands when kitting-out your SCAR.

The bolt and carrier are robust; that’s a lot of weight cycling back and forth. After shooting the 20S for a while, I installed the HDD Tactical buffer, which took a bunch of the sting out of the recoil. The recoil is “reasonable,” but for a 21st-century rifle of this weight, I was expecting more comfort. That I needed a shock buffer to “civilize” it indicates that the end users are a lot more interested in “always-reliable” than they are in “easy-to-shoot.”

The gas system is adjustable, but the adjustments extend to “normal” and “suppressed.” It isn’t as if you can dial down the gas flow until you get a softer recoil. (Hmmm, perhaps that’s something FN should look into.) The “suppressed” setting isn’t to ease up on felt recoil (remember that hard-chargers are the users in mind) but to keep the cyclic rate at normal levels when firing it with a suppressor on. Yes, the military models are select-fire, but we only have the option of one shot at a time. Still, setting it to “suppressed” when using a suppressor is the right thing to do.

On the SCAR, the upper is the firearm, not the lower.
On the SCAR, the upper is the firearm, not the lower.

The barrel is cold hammer-forged and then chrome lined. This gives a straight, smooth, stress-free barrel that’s both accurate and shrugs off use and wear.

The SCAR short-stroke piston system works the same way as on an M1 carbine (as compared to the long-stroke system of the M1 Garand, for example). The gas is vented out of the barrel and into the gas block, where it strikes the piston. The piston drives back and pushes the carrier assembly back. The piston stops but, having driven the carrier assembly, its job is done.
The carrier cycles back, rotating the bolt, then taking the bolt back, ejecting the empty and, on the return trip, stripping a round out of the magazine, rotating and locking.

One detail you must be aware of: the charging handle. It’s reversible to either side of the receiver and does reciprocate. That is, the handle cycles with the carrier, to which it is attached. If your thumb or hand happens to be up there in the path, you’ll get hurt, and the rifle will fail to cycle. (HDD Tactical also offers an angled charging handle to help keep it out of the way. It, too, is reversible.)

The magazines are modified FAL magazines, because FAL magazines were the starting point at which FN began. However, they’re not interchangeable in either direction (i.e., FAL to SCAR or SCAR to FAL).

The selector and mag catch are ambidextrous, while the bolt release isn’t. Not a big deal on the latter.
The selector and mag catch are ambidextrous, while the bolt release isn’t. Not a big deal on the latter.

The controls are where you’d expect them to be, with an ambidextrous magazine catch behind the magazine well, a bolt release only on the left and a safety selector (also ambidextrous) above the pistol grip.

Testing the SCAR 20S

The accuracy testing for the 20S involved installing a Leupold VX-3i LRP 8.5-25x50mm on top and in a Geissele Super Precision scope mount. Yes, this is pricey gear, but it provides a whole lot of performance for the money, and it’s not out of line with the cost of the rifle—or the ammo, per shot, really.

FN SCAR 20S Range Test

Shooting for groups with such a rig can be nerve-wracking. With a three-shot cloverleaf or a four-shot tight group, the thought, Don’t slap the trigger and ruin this group! looms large. In the course of testing, I was able to get to a private range at which there was steel out to 688 yards. Oh yes, that was fun! And even I, a hosing IPSC pistol shooter, could easily go nine out of 10 on the steel at 688 yards.

At no time did the SCAR 20S fail to function, and it was generous, but not excessive in its ejection.

The Good, the Bad, the Pricey

So, where does the SCAR 20S fit into the pantheon of rifles? Well, if you’re looking for a modern .308 thumper of the carbine and no-sniper variety (although still plenty accurate), you’d go with a SCAR 17. The M14 is long out of the military system, and the SCAR 17 fills the bill there. (There are AR-10 based rifles contesting the position of the SCAR 17. If and when that’s settled, we’ll all be the better for it.)

That’s a lot of mass reciprocating on every shot. That, and a generous flow of gas, is why you install a shock buffer in the rear of the receiver.
That’s a lot of mass reciprocating on every shot. That, and a generous flow of gas, is why you install a shock buffer in the rear of the receiver.

If you want a long-range, self-loading sniper rifle, you’d be hard-pressed to beat the SCAR 20S. However, you’ll have to deal with some issues.

First off, the bottom handguard assembly isn’t the same as that of the 17. So, what about all those accessory rails, handguards and add-ons for the SCAR 17? They won’t fit. Until aftermarket makers, or FN, makes lower handguards for the 20S, you’ll get what there is. The stock doesn’t fold—and the adjustments, while useful, don’t make the 20S any handier. In addition, you have to use the FN magazines. I don’t know of anyone else who’s currently making magazines for the SCAR, so you’ll have to stock up through FN or some other supplier … at almost $50 each.

A minor complaint: The flash hider rings like a tuning fork on every shot. Now, if you’re swapping it out for a muzzle device to mount your suppressor, it’s not a problem. But if you aren’t, you’re going to want to change that just as fast as you can, because it’s damned annoying.

And then, there’s the cost: $4,500. Now, to be fair to FN, you’d eat up a significant amount of that buying an AR-10-based rifle of the same or nearly the same quality—and then you’d have to change what you needed to change to make it the functional and detail equivalent of the SCAR 20S. So, you aren’t going to save much money by “almost equaling” it with some other rifle. Just be prepared for the sticker shock.

The annoying, pinging flash hider—a tuning fork on every shot.
The annoying, pinging flash hider—a tuning fork on every shot.

On the good side, there’s the plethora of rails. The full-length rail on top is almost too much. There are rails on the sides, and the bottom of the handguard offers plenty of space to mount whatever else you need. You have plenty of options, but they’re all Picatinny—no Keymod or M-lok.

For the bulk and weight, once you get the stock adjusted, the rifle fits like a glove. And then, there’s the trigger. FN is coy and understated on the trigger weight on its website, simply stating that it breaks crisply at 3.5 to 4.5 pounds (that’s like saying Sofia Vergara is a “nice-looking” lady).

I’m a spoiled gun writer. I usually consider any trigger installed in a factory-built firearm as a starting point; one that’ll be changed as soon as possible. The trigger on the 20S that FN sent to me doesn’t need changing. I don’t think you would, either. But then, you wouldn’t have to, because upon opening the action, what do I find? A Geissele Super SCAR two-stage trigger … which is what I would’ve put in had the trigger disappointed.

Fun’s fun, but I can’t pay the mortgage by trading guns to the bank. As a result, the 20S will have to go back to FN. If this one ends up in the commercial stream—and not to another gun writer—someone is going to find a superb trigger and cracking good accuracy, as well as a lot of fun, with this 20S. And, given the longevity of FN’s barrels, it’ll still be whacking steel at 700 yards, even after it has passed through the hands of a half-dozen gun writers.

FN SCAR 20S Specs
Type: Gas-operated, self-loading rifle
Caliber: .308 Winchester/7.62 NATO (also available in 6.5 Creedmoor)
Capacity: 20+1 rounds
Barrel: 20 in.
Length: 42.5 in.
Weight: 11 lb., 3 oz.
Trigger: 3 lb., 7 oz.
Finish: Anodized aluminum, black-oxide steel
MSRP: $4,499

For more information on the FN SCAR 20S, please visit fnamerica.com.

Editor's Note: This article originally appeared in the September 2020 issue of Gun Digest the Magazine.


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  1. Soes FN make ANY model SCAR W/O a reciprocating charging handle??

    I will not buy a semi-auto with a reciprocating charging handle. I have an FN PS90 with a NON-reciprocating charging handle. Love that little carbine – and my RUGER 57 pistol.


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