Are the FN SCAR Weapons (MK16 and MK17) Necessary? And do we really need to replace the Colt M4/M4A1 Carbine?

By David Crane
defrev (at) gmail (dot) com

May 20, 2009

According to Army Times magazine, The 75th Ranger Regiment is scheduled to battle test the Special Operations Combat Assault Rifle (SCAR) very soon. The Rangers will reportedly be taking 600 FN SCAR rifle/carbine/subcarbine/SBR (Short-Barreled Rifle) weapons packages into battle, but DefenseReview doesn’t know how many of these are the 5.56×45mm NATO (5.56mm NATO) FN MK16 (formerly SCAR-Light a.k.a. SCAR-L) assault rifle/carbine/subcarbine/SBR variant, and how many are the 7.62×51mm NATO (7.62mm NATO) FN MK17 (formerly SCAR-Heavy a.k.a. SCAR-H) battle rifle/carbine/subcarbine/SBR variant.

The SCAR weapons are select-fire and operate via a short-stroke gas piston/op-rod (operating rod) (SSGP/OR) mechanism vs. the Colt M4A1 Carbine’s direct-gas-impingement (DGI) a.k.a. direct-impingement gas (DI gas) operating mechanism and were designed and developed to replace the Colt MK18 CQBR (Close Quarters Battle Receiver) 5.56mm SBR, Knight’s Armament (KAC) MK11/SR-25 7.62mm semi-auto sniper rifle, 5.56mm MK12 SPR (Special Purpose Rifle) (5.56mm), and the M14 7.62mm battle rifle. The SCAR weapons are modular, and military operators can choose barrel lengths of approx. 10″, 14″, and 18″ for the MK 16 and approx. 13″, 16″, and 20″ for the MK 17. The MK16 takes a 30-round magazine, and the MK17 takes a 20-round mag. The SCAR weapons offer a reported 80% parts commonality between the two variants.

Defense Review recently spoke to one of our professional contacts in the tactical firearms community, and he told us on the phone that the MK16/SCAR-L is for all practical purposes “dead”, meaning that it’s not likely to survive for very long, and that the SCAR weapons are continuing to experience teething problems in the field, i.e. breaking down. We don’t have confirmation/verification on this yet, so it’s just a rumor at this point. Anything’s possible, but we’ve spoken with people in the U.S. military Special Operations community who prefer either the AR-config HK416 (also written HK 416) for a gas piston/op-rod carbine/SBR solution or a good old-fashioned DGI Colt SOPMOD M4A1 Carbine or MK18 CQBR SBR for a DGI solution.

On the subject of piston-driven vs. direct-gas-driven weapons, while gas piston-driven weapons have been all the rage over the last few years, there’s a growing list of tactical AR cognoscenti, aficionados, and builders that are pushing back againt the march to gas piston/op-rod Nervana, making the case that piston-driven systems may not necessarily be a better mousetrap after all, and in a number of ways, are actually inferior to the combat-proven DGI operating system.

Direct-gas-impingement operation offers significant accuracy and weight advantages over gas piston/op-rod operation in AR (AR-15)-config weapons. For example, Heckler & Koch (HK) had to significantly thicken the barrel on the HK416 (also written HK-416) to counteract barrel flex caused by the forces exerted by the offset, reciprocating gas piston and operating rod. This barrel flex resulted in accuracy problems and vertical stringing of shots during full-auto fire. Understand that a gas piston/op-rod setup is already inherently heavier than a direct-gas-impingement setup, and thickening the barrel made the HK 416 heavier than it initially was.

It should perhaps be noted that a primary reason for the movement towards short-stroke gas piston/op-rod operation (and the use of the HK416 SBR, specifically) instead of direct-gas-impingement operation by elements in U.S. Army Special Forces and U.S. military Special Operations Forces (SOF) out of USSOCOM a.k.a. SOCOM was due to their desire to suppress 10.5-inch (10.5″)-barreled SBRs. Attaching a silencer/sound suppressor a.k.a. “muzzle can” to carbine or SBR changes the pressure and fouling dynamics of the weapon, and can cause reliability problems unless the weapon is specifically set up for suppressed use.

Even without a can attached, at 10.5″ inches, a DGI-operated AR15-config weapon like the Colt MK18 (formerly known as the Colt M4A1 CQBR)–which actually utilizes a 10.3″ barrel–is a bit too close to to the precipice of not working reliably, since the direct-gas operating system relies on a certain amount of barrel length to creat the correct amount of gas pressure for the correct amount of time, as well as a consistent level of gas pressure over time, to cycle the action (i.e. the bolt carrier group) and feed the next round. This “timing” element is crucial in a DGI AR-15 SBR for combat reliability. A suppressor just adds to the inherent and somewhat precarious pressure curve/timing issues of an AR-15 SBR.

However, if you add a high-tech self-lubricitous / self-lubricating, anti-rust/corrosion internal coating and a Precision Reflex (PRI) M84 Gas Buster Charging Handle - Military Big Latch, to a direct-gas AR, it may be possible to at least address the fouling issue. With this type of coating, DGI weapons may be able to handle the suppressed role (silencer/sound suppressor a.k.a. “muzzle can” attached to the weapon) just as effectively as a piston gun (unconfirmed/unverified). DefenseReview would have to test this, theory, however, and we may do this soon. The PRI M84 Gas Buster Charging Handle attenuates/mitigates hot gas and particulate matter backblast into the shooters face, which has been a criticism of suppressed DGI AR carbines and SBRs, including the M4A1 Carbine.

High-tech firearm coating technologies such as the Next Generation Arms (NGA) internal ceramic coating, the FailZero “AR-15 Basic Kit” and “AR-15 Extreme Duty Kit” nickel-boron (Ni-B)-coated AR-15 parts and components, and the Robar NP3 PTFE (polytetrafluoroethylene) a.k.a. Teflon)/electroless nickel coating/finish may reduce/mitigate internal “crud” a.k.a. fouling build-up inside a suppressed DGI AR-15 carbine SBR enough to allow it to work reliably at a high-enough round count to negate the gas piston/op-rod system’s advantages in this specific area. We’ll see.

It’s noteworthy that tactical instructor, author, and DefenseReview contributor Mike Pannone, a retired U.S. Army Special Forces (SF) operator, prefers a 12.5-inch (12.5″) barrel for a direct-gas-impingement AR-15 SBR. Since a 12.5″ AR SBR can utilize a standard carbine-length gas system (DGI), Pannone believes that 12.5 inches is the optimum barrel length for a DGI AR SBR, since it provides for optimum weapon utility. Basically, a 12.5″ AR-15 SBR offers the perfect balance of weapon compactness and versatility, reliability (provided by adequate barrel length to achieve the right pressure curve and timing), and muzzle velocity for adequate terminal ballistics/lethality. The one caveat is that the weapon has to be set up right, or “sprung right”.

In order to ensure this, Pannone developed the BHI Enhanced M4 SOPMOD Bolt Upgrade Kit being sold by Blackheart International (BHI), which, according to him, will solve the majority of M4/M4A1 Carbine and semi-auto-only AR-15 carbine reliability problems, all by itself. The kit includes a mil-spec extractor with a 5-coil extra-power extractor spring, Crane O-ring to elimate extractor bounce, 3 mil-spec gas rings, a mil-spec Black Buffer (H2 buffer), which also reduces exractor bounce, a Sprinco Extreme Duty Buffer Spring/Main Spring, which lasts 4-5 times longer than a standard buffer spring and “adds additional tension to absorb recoil; energy, and ensure reliable feeding, chambering and locking”, and a DPMS Rate Reducing Buffer. BHI says the following about the DPMS Rate-Reducing Buffer: “This buffer, along with the upgraded buffer spring will absorb more energy as the bolt cycles to the rear, slowing the bolt velocity and giving the shooter a much more manageable recoil impulse, and a decreased rate of fire on full-auto carbines. The heavier buffer will also ensure that feeding chambering, and locking on even a dry dirty chamber is positive and reliable.”

Provided the M4A1 Carbine (or semi-auto-only AR-15 carbine) is properly maintained by the end user and “sprung correctly”, i.e. outfitted with a BHI Enhanced M4 SOPMOD Bolt Upgrade Kit, Pannone argues that you’d be hard pressed to find anything better (i.e. more reliable), or even as good as the combat tested-and-proven Colt M4A1 Carbine.

It should perhaps also be noted that high-end tactical AR (tactical AR-15 weapons platform) builders John Noveske of Noveske Rifleworks, LLC and Nathan Roads of Next Generation Arms (NGA) both prefer direct-gas-impingement AR-15s to gas piston/op-rod ARs. DefenseReview found out about Noveske’s preference for DGI ARs during one of our interview sessions with him. Noveske and Roads also like the 12.5″ barrel length for DGI AR-15 SBRs.

So, does SOCOM really need the FN SCAR MK16 and MK17 weapons? Probably not. The fact is, while the SCAR family might potentially provide modularity and production cost advantages over the long term if SCAR is eventually adopted and it replaced all the weapons listed above that it’s intended to replace, it doesn’t offer any lethality advantages whatsoever over any of the already-fielded, combat tested and proven weapons it was designed and developed to replace.

The SCAR weapons simply aren’t revolutionary in any way with regard to combat capability and effectiveness. If anything, they’re more of an interim-level/bridging-the-gap solution until somone develops a truly revolutionary replacement for our currently-fielded weapons. Fact is, the MK-16/SCAR-L is a much more expensive proposition in the short term than just properly maintaining the legacy M4/M4A1 Carbines that are already in the system. Fact is, many SOCOM operators already prefer the HK416 (5.56mm) and HK417 (7.62mm) carbines and SBRs over SCAR for a short-stroke gas piston/op-rod weapon solution, if they’re going to replace the combat-proven M4A1 with anything. Fact is, the financial health of the U.S. military procurement system isn’t what it once was, due in large part to the financial realities of the country in general. And, fact is, there’s a new sheriff in town (Obama), and Demcocrat administrations aren’t traditionally conducive to a high level of military funding and support, at least not in the modern era.

And, again, rumor has it that SCAR weapons are breaking in the field (unconfirmed/unverified). Oh, and speaking of breaking, The HK-416 has apparently been experiencing its own share of parts breakages and reliability issues in the field, as well. Defense Review will further investigate the specific problems we’ve heard about for SCAR and the HK 416 as soon as we can.

Bottom line is that as time goes on, SCAR is looking more and more like an unnecessary indulgence and a waste of increasingly-scarce taxpayer dollars.

Editor’s Note: Mike Pannone (a.k.a. Michael Pannone) is the author of the M16/M4 Handbook and HK416 Handbook (also written HK-416 Handbook), which are invaluable resources to anyone who owns and/or uses an M4/M4A1 Carbine, tactical AR-15 carbine, or HK416 respectively. They’re also worthy additions to any tactical firearms library, even if you don’t own or use any of those weapons.

Company Contact Info:

FN Herstal USA (FNH USA) Military Operations
PO Box 896
McLean, VA 22101
Phone: 703-288-3500
Fax: 703-288-4505
E-Mail: militaryinfo@fnhusa.com
Website: http://www.fnhusa.com

FNH USA Military Training Operations
Phone: 1-540-752-6200
Fax: 1-540-752-0967

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JackandBlood

Ya I'm starting to lose a bit of faith in this site (which I loved cuz it shows off cool gadgets and im a mil-history enthusiast). But the format is drastically different And. Between this apparent shift in AR operation love, and the the ambiguities of "Dragon" bodyarmor, which had once been a hot topic for DR, im thinking new management, proponents of the status quo.

Kev

While the M4A1 has its strengths (particularly in modularity), my personal experience with the AR-15 family has been rather disappointing. On the range, I've tried three different AR's--one from DPMS, another from Bushmaster, and one from Colt itself. All three of them jammed within the first two magazines. The Colt had the most catastrophic failure, and had to be taken to the shop to be fixed. Even after it had been cleaned and repaired by the gunsmith, I still encountered frequent jams. By contrast, the AK clone I used performed flawlessly.

Perhaps I'm just an unlucky person, but I have serious doubts that the DGI system is really all that it's cracked up to be. There are plenty of highly accurate piston-operated assault rifles out there--look at the SIG 550. As for the issue of piston movement distorting accuracy, you may be interested in the AK-107's balanced operating system.

DefRev

Kev, would it be possible to get a contact email address for you? I'd like to touch base with you on something regarding your post (nothing bad, I assure you), if that would be possible. If so, please contact me at defrev (at) gmail (dot) com.

Thanks,

David Crane
Owner/Editor-in-Chief
DefenseReview.com
defrev (at) gmail (dot) com

tacticalsquirrel

kev i think you are the problem..not the rifles.

Kev

@tacticalsquirrel: In a way, I wish that were the case...I initially wondered if I was simply not operating them properly, but even when I was supervised by people with far more AR experience with me, I still had the exact same problems.

Don't get me wrong, I think that AR-15s/M16s/M4s are good weapons if you keep them in tip-top shape...it's just that I worry about what happens when conditions are less than ideal.

Tucker

Only once in the history of the US military have we changed primary small arm without changing caliber and that was a major system change from bolt action to semi-auto (and the M1 Garand was not originally designed for the .30-06). Changing from the M16/M4 to a 5.56mm piston gun that offers limited improvements at best is a waste of resources. Having carried M16 based rifles for eighteen years now I have no real complaints. If I have any problem it is with the ammo we are issued that is geared primarily towards punching armor and less then optimized for disrupting tissue

DefRev

Please see reply above.

weaponsandammunition

If what I read is true about the SCAR weapons - then they will do very well in battle, I hear they perform better than any previous riffles that industry has made and they also have a more manageable recoil impulse, this will make all the difference when firing under pressure.

Tim L

I can understand your desire to speak to a wide variety of experts about M4's and it's more modern replacements with regards to the use of these weapons in the field as they would have valuable insights into the issue, but my first reaction of reading this report was that Mr. Noveske and Mr. Roads do have a vested interest and would be partisan to say the least with continuing the status quo. Not to say that their input is not valid but it may be rather biased considering that they have significant financial investments into these matters.

JackandBlood

Look im a civilian with little experience. Hell all i've shot is a glock 17 a friend and I rented at an indoor range. But what i've read in Not a good day to die worries me. In Operation Anaconda, a small group of recce SEAL team (Mako 31) encounters a Dshkm position. They engage the target. Two of the 3 that are in direct contact have their guns (M4s) jam after the first shot. Its only by the virtue of the 3rd SEAL's marksmenship that 3 of the 5 enemy are eliminated. AC-130 eliminates the two retreating Al-Quida. I could give a tuppanny fuck about new ammunition or calibers, but as a taxpayer, and one who appreciates the work of our men in the field, I want our regular infantrymen to have the BEST POSSIBLE GEAR. It does not matter if they are the 'mere' riflemen, they are Americans and deserve the best.

James Wu

JackandBlood

And i dont hold a '100% minimal, unquantifiable improvement' as a reason to discount whats in the interests of the common rifleman.

crisemurray

The real reason for SCAR was ownership of M4s that USSOCOM was using, "Big Army" didn't always like the unauthorized modifications or untested attachments that USSOCOM guys were putting on their weapons; so USSOCOM decided to get their own gun. Anybody with "Special" in their unit name doesn't need a rifle, they haven't won a gun fight in over 40 years without air support. Give them cool hats, sunglasses and a good radio, because at the first sign of enemy activity they're going to call for air support anyway. Give them a pistol to fight off drunk hookers.

Name

I have several DI and piston setups and have tuned them all. Not a single issue past break in. The SCAR might be great but I find it hard to believe we need a new system. For my money the Colt or LMT are the way to go.

Hibuke

The author clearly has a biased opinion. I've served with an Asian Army which still uses the AR15/M16 and we encounter problems every single day even out on the range, after METICULOUS cleaning. Whatever the case, the HK-styled solution is ideal... I agree with Kev; *IF* the AR/M16/M4s are kept in tip-top shape *AND* (this is my input) fired on single *ONLY*, you'll have quite a fine weapon..... *BUT* these two factors that *CANNOT* be guaranteed out in the field, in combat when the SHTF.......

At best, the AR/M16/M4 is a good SWAT/Paramilitary weapon, but by no means whatsoever is it capable nor should it ever be considered a full-combat weapon that our soldiers are depending on with their lives and, heck, yours and mine on the line!

proinfidel

I think your reporting of the SCAR, and HK416 breaking down in the field, without your knowing that for a fact is very unprofessional. I might as well just read the National Inquirer for my defensive weapons info.
I always considered your site a great source of information, but that was in the past, and I do not think I will be reading your rumor pages any more.

captadrianadrianalexandrino

First time reader and so far am very pleased with the sight. As for me the only major problem that i have feaced with my ar platform (S&W mp15) has been feeding problems with the use of magpul magazines.

Name

I have a 11.5" M-16. Gas port is at .087".Bolt and carrier were first polished before coating with nickel-teflon(this makes a big difference).Upper receiver was polished with fine rubbing compound but not coated with nickel-teflon.Using the flat wire recoil spring from Tubbs ( ISMI spring i believe) and Advanced Armament rate reducing buffer.Works great with or without suppressor.The polished and coated bolt&carrier wipe off very easily.Will have to try the gas buster.

akfisherman1969

I will address several of the comments below, as well as the original. To all of you who support the AR-15/M-4 series rifles over the SCAR, I have one question. When is the last time you ever smoked someone at 10-20 feet? From experience, I will tell you, there are reasons that Special Operations units carry both an M-4, and a side arm. The M-4, although a good rifle (many little brown guys have met their match with this weapon), has it's limitations. As a long time SOF shooter, I got to play with the MK17 today for the first time (SCAR-H), and I will say, that it was "spiritual event". The gas-piston operating system versus the gas-impengment system is not even a real comparison. Piston wins hands down for reliability and durability in combat conditions. My only bitch with the gun was that the selector lever was a little short for my Irish thumbs (kind of reminded me of the MP-5 in this area), and the selector was kind of sloppy. While moving, most of us have our thumb on the selector, full-time, in order to ensure that our gun is safe until we have identified a threat. With the SCAR, if you aren't over 6 feet tall and have ape thumbs, you will have to totally re-learn your muscle memory. Over all, I give the SCAR two thumbs up. I would place the MK17 heads and tails above the M4 and M4A1 due to the fact that it takes a lot more dirt and carbon to cause malfunctions, and that I have personally put up to 10 rounds of 5.56mm M855 (standard issue) into LBGs at as little as muzzle to chest, and they take forever to plant their faces on the floor. The 7.62 MK17 will not need multiple shots, it does the job in a few shots. (Oh, and to those who think that I just don't have good shot placement, you obviously haven't shot a bunch of man dress wearing zealots. Unless you hit the brain stem, or the spine, don't count on them dropping. Rule of thumb. Shoot until their face hits the floor, then add two more.

bacsi

Lots of good men died in nam because of the fouling problems inherent with the sorry M16 design - 50 years later it's still the same sorry design. Chopping the barrel off and calling it a M4 is ludicrous on its face - barrels and ammo have to be matched. Billy Boy Clinton completed the farce in the name of Mother Earth by destructing the ammo with the change from lead to titanium... the Only thing the M16 ever had going for it was the round - hit someone in the arm or leg it would turn the muscles to mush and rip it off if it hit a bone. No one survived two solid shots to the chest with a M16 in nam, but I've treated troops who survived five AK rounds in the chest. Now there are more cases of bad guys continuing the fight after repeated solid shots to the body than I can recall. For urban house to house warfare the M4 is a joke, it can't penetrate walls and a whole squad of M4s can't even stop a Toyota sedan. For war fighting in the mountains of Afghanistan it is another joke - no hitting power at any range, much less alone at what is encounter in that terrain. I'll take an M14 any day of the week, and if I have to do something serious I'll get a BAR, and at my side will be strapped a Colt 1911. The War-Industrial Complex got our number a long time ago, boys: worthless Colts, FNs, HKs, and Berattas... John Browning's ghost must be having a fit.

11bravo

As a soldier, the politics that surround the choice of the best weapon for our troops is disgusting. I am not sure who's pockets the people at Colt have lined, but it seems to be working. The gas-piston system seems to be the only way to go due to reliablity. I don't think it really matters if Colt Defense makes it or not, but there seems to be other companies out there that can compete with Colt in the production of upper's for today's M4 lowers. Every red blooded patriot proclaims that we need to give our troops the best equipment and weapons available, but we've been using the same rifle (based on the same design without any major changes) for the last 40-50 years. Come on lets practice what we preach.