IAR What IAR: The USMC’s SAW Substitution

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M27 IAR, Afghanistan(click to view full) The US Marines have been using the M249 5.56mm light machine gun since 1984. Many were worn from use, and at 15-17 pounds empty, these belt-fed weapons are rather heavy. They can be more hindrance than help in some of the close-quarters urban warfare situations dominating current battlefields, especially […]
M27 IAR firing

M27 IAR, Afghanistan
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The US Marines have been using the M249 5.56mm light machine gun since 1984. Many were worn from use, and at 15-17 pounds empty, these belt-fed weapons are rather heavy. They can be more hindrance than help in some of the close-quarters urban warfare situations dominating current battlefields, especially since they have a reputation of jamming more often than standard rifles.

Their initial 2005 FedBizOps.com solicitation for an “Infantry Automatic Rifle” (IAR) wanted two big things. First, the gun had to fire from either the open or closed bolt position. This would give it the single-shot and “first through the door” capabilities that the M249 lacks, while allowing for more sustained fire than an M16 can handle without risking ammunition “cook off” in a heated barrel. It also had to be considerably lighter than the M249, at just 12.5 pounds maximum and 10.5 pounds desired weight. In exchange, the Marines decided they were willing to trade the SAW’s belt-fed design for switchable 30 round magazines, which are used up much more quickly but can be changed in battle much more quickly.

The result was not a true light machine gun, but something in between an LMG and an assault rifle. That shift in the 13-man Marine squad has its advocates and detractors. DID offers more background concerning the USMC’s IAR contenders, contracts… and controversy.

IAR What IAR: The Choice

M249 SAW loading

M249 SAW, loading
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The larger questions around these weapons boil down to doctrine. Light Machine Guns can be used for sustained “suppressive fire,” but often pay a price for doing so. The price is paid in weight and accuracy. The benefit is that keeping the enemy’s head down has considerable defensive value, and frees up your own side to maneuver.

Until recently, the Ultimax 100 has been the closest thing to an LMG that could comfortably switch over into “heavy assault rifle” mode, without losing its basic function. The IAR is that magazine-fed heavy assault rifle, but its 30 round magazine can make sustained suppressive fire difficult unless several IAR operators are on hand.

Drum magazines can be used to increase the number of available rounds, but loading them is difficult, many drum magazines have reliability issues, and carrying multiple drum magazines is a lot bulkier than carrying multiple 30-round ‘flat’ magazines. In practice, therefore, the IAR is likely to be a 30 round weapon that depends on accuracy for suppression.

A recent USMC battle at Shewan, Afghanistan indicates that this may be possible. In addition, marksmanship and the ability to bring a weapon to bear very quickly are hallmark requirements of the urban battlefield, where the Marines and militaries around the world expect to do a lot of their fighting over the next few decades.

On the other hand, there’s a psychological dimension to combat. Crossbows fired faster than muskets, and were much more accurate. They were replaced by muskets because the musket’s psychological effect had that much value in a real fight. In a similar vein, USMC Commandant James Conway has expressed concerns about giving up the light machine gun’s lower accuracy coupled with suppressive and psychological value.

In the military world, as in the world of finance, options have value. The Marines’ decisions to date have indicated the priority they place on more optimized IAR designs, which may not be true LMGs but offer other advantages in compensation. That stance has now come into some question, and the questions emanate from the very top of the Marine Corps. The encouraging signal in all of this is that the question will be settled by combat trials, not bureaucratic infighting.

The IAR emerged from that process as the M249’s replacement, and the Marines may expand its role further to include sniper platoon and dedicated marksman roles.

The Contenders

The Finalists

In December 2008, the winning short-list picked a set of long-established competitors.

HK416 Labeled

HK416, labeled
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Heckler & Koch (winner). The HK416 is an M16/M4 with a modified upper receiver. US SOCOM and other special forces around the world have been using them for several years now, after the standard Colt M4 design proved itself unable to meet SOCOM’s needs.

H&K replaced Colt’s “gas-tube” system with a short-stroke piston system that eliminates carbon blow-back into the chamber, and also reduces the heat problem created by the super-hot gases used to cycle the M4. Other changes were made to the magazine, barrel, et. al. The final product was an M4 with a new upper receiver and magazine, plus H&K’s 4-rail system of standard “Picatinny Rails” on the top, bottom, and both sides for easy addition of anything a Special Operator might require. In exhaustive tests with the help of the USA’s Delta Force, the upgraded weapon was subjected to mud and dust without maintenance, and fired day after day. Despite this treatment, the rifle showed problems in only 1 of 15,000 rounds – fully 3 times the reliability shown by the M4 in US Army studies. The H&K 416 was declared ready in 2004, and there is also an HK417 version in 7.62mm NATO caliber.

In October 2009, H&K’s 416-based IAR design won. It was later given the USMC designation “M27.”

Colt CAR

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Colt. The current manufacturer of the M4 carbine, who also makes some of the Marines’ M16 rifles. Colt publicly touts a variant of its CAR design, which is called the LSW by Colt Canada and serves with customers that include the Netherlands. It’s basically an M16, with some modifications including a new hydraulic buffer assembly and a heavier barrel. Elsewhere, Defense Review has a complete review of the Colt IAR, which appears to be a different design than the CAR. It uses a direct gas impingement system rather than a gas piston system, and adds a large heat sink to the front which makes the 9.5 pound weapon a bit front-heavy.

Interestingly, Colt won 2 contracts for the IAR’s development and testing phase. It’s not clear if that represented CAR and IAR awards, or if the twin contracts had a different set of dual competitors. Regardless, neither won.


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FN USA. The US Marines are already a customer beyond the M249 SAW, as FN USA manufactures many of the Marines’ M16 rifles. For the IAR competition, the firm entered a version of the SCAR-L Mk16 rifle that had become US Special Operation Command’s weapon of choice. FN’s SCAR family of rifles has a wide set of innovative features developed with SOCOM’s assistance over the last several years, and a 10-year production contract was awarded in November 2007. FN USA’s IAR entry is interesting, in that it retains the accuracy and performance of closed-bolt firing until the barrel reaches a certain temperature, whereupon it automatically switches to safer open-bolt firing.

With MARSOC operating as part of SOCOM, a number of Marines may already be familiar with this weapon via cross-training. Since the Marines plan to rotate personnel back to regular Marine units after MARSOC, a rifle that’s shared with SOCOM could offer certain advantages to the force.

That’s no longer true, however – in June 2010, SOCOM decided to cancel further SCAR-L Mk.16 purchases on cost and efficiency grounds, and will probably recall the 850 fielded weapons, rather than continue to support them. SOCOM will be adding to their stock of 750 SCAR-H Mk.17 7.62mm riles, however, and will field an extended SCAR-H Mk.20 with sharpshooter enhancements.

Other Candidates


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Some firms that were expected to be contenders for the IAR did not make the shortlist.

General Dynamics. The firm had partnered with Singapore’s ST Kinetics to offer a Mk5 version version of the Ultimax 100 5.56mm light machine gun, whose accuracy and control have deeply impressed many military observers and analysts [watch video – AVI format]. Part of the weapon’s secret is that it was originally designed for Singapore’s smaller soldiers, and the 11 pound Ultimax LMGs (when empty) now serves with a number of militaries around the world.

The Ultimax was not ready in time to dislodge FN’s M249 in the original SAW competition, but the Marines had maintained a simmering interest in the weapon ever since. General Dynamics hoped that this time will be different, but the IAR’s specifications and focus appear to have handicapped this entry, and it was not selected for the IAR development contracts.

LWRC. This firm has done a lot of work refining and improving the M16/M4 for military, law enforcement, and personal use. This includes the introduction of more reliable mechanisms, designated marksman weapons, and even different calibers like the superior but magazine-compatible 6.8mm. Their 5.56mm “M6A4 IAR” candidate was not selected for additional development and testing.

Contracts and Key Events

In September 2008, Gannett’s Marine Corps Times reported that only some of the USMC’s M249 SAW weapons would be replaced. The eventual contract announcements, however, specifically mention the option of replacing all M249 SAWs used by the USMC’s infantry and LAR battalions.

FY 2011 – 2013

M249 Helmland

M249 SAW, Afghanistan
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Nov 12/12: The Pentagon’s DVIDS covers the IAR’s ongoing integration into the Corps, and the fade out of the M249 Squad Automatic Weapon. The Marines chosen for the article cite its direct piston system, fewer moving parts, easier maintenance, and greater accuracy.

Some of the Marines quoted are talking about using the IAR in sniper platoons, and as a dedicated marksman weapon in standard platoons. Chief Warrant Officer 2 Chris Jones, infantry weapons officer, 2nd Bn., 7th Marines:

“In the current fight when there is a limited exposure and a fleeting target that blends in with the local populace, it is more important to have a more accurate rifle with a better optic. If you can get (positive identification) faster, you can kill the enemy rather than a weapon that provides audible suppression. Audible suppression being the bullets hitting everywhere but on target, and the enemy only hearing the sounds of gunfire.”

Nov 17/11: No expansion, no IC. Military.com reports that the USMC has considered he M27 IAR as a future individual weapon, but decided to stick with improvements to the M16A4 rifle. This also means they won’t be adopting the winner of the Army’s Individual Carbine competition, which was opened to new manufacturers and even new calibers.

MARSYSCOM commander Brig. Gen. Frank Kelley adds that the 450 M27s fielded to 5 infantry battalions headed for Afghanistan have been performing “exceptionally well,” and believes that the Marines will finish fielding more than 4,000 M27s by April 2013.

Sept 15/11: HK USA announces a 5-year, $23.6 million Full Rate Production contract for production and support of the M27 IAR. That’s the maximum amount listed in the Dec 22/08 contracts.

Formal approval for full rate production and fielding took place during the summer, which will lead to over 4,000 rifles issued throughout the USMC.

Full-Rate Production contract

FY 2008 – 2010

M249 SAW firing

M249: not ideal
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July 1/10: Limited approval. Media outlets report that in April 2010, USMC Commandant Gen. James T. Conway gave Corps officials the green light in April to issue approximately 450 H&K M27 IARs, enough to replace every M249 squad automatic weapon in 4 infantry battalions and 1 light armored reconnaissance (LAR) battalion. Each company in the 3 active infantry battalions and reserve battalion will receive 28 M27s: 1 for every SAW gunner, and 1 extra for the unit. These companies will also retain 6 M249s. The LAR battalion will receive 14 M27s, and completely replace its M249s.

The Corps intends to give these units 4-6 months of pre-deployment training with the new weapons, and they are expected to be in Afghanistan around November-December 2010. Assessments from the Marines in theater will determine whether or not the IAR program resolves the Commandant’s doubts, and continues into full production of about 4,476 M27s. Marine Corps requirements officials hope that Conway will decide whether or not to take the IAR into full-rate production by late 2011, after the field reviews are in.

The biggest issue may turn out to be a factor that hasn’t featured much in debates so far. The US Army (M14) and the British (L129A1) are both turning to 7.62mm IAR-type heavy assault rifle/ marksman weapons in Afghanistan. Its wide open spaces are creating long-range firefights where 5.56mm rounds become ineffective, but the enemy’s 7.62mm rounds remain so. The HK417 is the 7.62mm variant of the HK416, and a 7.62mm IAR could indeed trump short-range LMG suppression – but a decision to change calibers would almost certainly re-open the competition. Gannett’s Marine Corps Times | Military.com

Limited approval for 450

June 8/10: Magic magazines? The Firearms Blog highlights magazine maker Magpul’s recent patent application (#20100126053) for a quad stack AR-15 compatible magazine, complete with diagrams. A central partition separates 2 dual round stacks, with an asymmetric transition area. This could give the IAR its 50 round magazine, joining Russia’s new AK-200 Kalashnikovs with their 60 round quad-stack magazines. The Firearms Blog | Military.com Kit Up!

Dec 28/09: Doubting Conway. The IAR is facing skepticism at the very top of the Marines Corps. The issue is not performance to spec, but the trade-offs that the program has chosen to make. USMC Commandant Gen. James T. Conway, at a press conference:

“I do have concerns, and those concerns have not been abated at this point… In terms of accuracy, there’s probably no comparison… Let’s step away from accuracy for a moment and talk about suppression, and the psychology of a small-unit fight, that says if other guy’s got a light machine gun and I’ve got an automatic rifle, I’m going to be hard-pressed to get fire superiority over him, you know, to keep his head down instead of him keeping mine down, because that 200-round magazine just keeps on giving… let’s talk about what it does to squad tactics… every 30 rounds, you gotta change magazines. Well, you’re probably not gonna do that, y’know, in an exposed position… fire superiority is fleeting… I’m concerned that moving at night… the other squad members carrying those additional magazine for that automatic rifleman, might in a spread formation be hard pressed to get him what he needs in a timely fashion…

I don’t want to get so far in the weeds… but it’s a big deal when you start changing how a Marine infantry squad fights, and, and, we’re gonna treat it as a big deal [raps table for emphasis], and I’m gonna have to be convinced that we’re making the right move before we start to purchase another system and change that whole dynamic… [especially when the Army is not taking this approach]. So there’s another additional burden of proof here that has to be met…”

Nov 24/09: Gannett’s Marine Corps Times reports that the USMC is re-thinking its decision to drop the IAR’s requirement for a high-capacity magazine. A recent solicitation for a high-capacity magazine that could hold 50 or 100 rounds and fit “the M16/M4/HK 416 family of weapons” seems tailor-made for the IAR.

The magazine adds that the Modern Day Marine 2009 exposition saw FN Herstal display a 100-150 round magazine for its FN-SCAR IAR variant, while Armatac Industries has approached the Corps about a compatible 150-round 2-drum magazine that it says is compatible with each of the finalists weapons.

Early in the evaluation process for the IAR, the Corps’ requirement called for the weapon to use 100-round magazines. That was eventually eliminated in favor of using the same 30-round magazines, as Marine officials sought to cut weight from the SAW’s replacement.

October 2009: Marine officials pick Heckler & Koch’s 5.56mm HK416 derivative IAR over Colt and FN Herstal’s designs, and order another 24 additional weapons for more testing at various USMC facilities including Twentynine Palms, CA; Fort McCoy, WI; and Camp Shelby, MS. The award is framed as a “downselect” rather than a contract win, which indicates that Keckler & Koch’s design is a front runner for now, rather than an ultimate winner. Media reports began in December, and Gannett’s Marine Corps Times adds that:

“A formal protest was filed with the Government Accountability Office by FN Herstal to a Marine contract decision on Oct. 30 and updated on Nov. 23, but GAO officials declined to discuss whether the protest was related to the IAR decision. Colt currently has no contract protests filed with GAO.”

The new “M27 IAR” reportedly weighs 7.9 pounds unloaded, which is very close to a regular HK416, and much less than the M249 LMG’s 17 pounds. It uses a short-stoke gas piston, which is far more reliable and resistant to fouling than the M4/M16’s direct gas system. What it doesn’t have is a quick-change spare barrel to prevent overheating, which will limit it to 65 rounds per minute using 3-round bursts, compared to the M249’s recommended 85 rounds per minute, firing continuously while the trigger is depressed. Gannett’s Marine Corps Times report, GearScout blog entry, and Update | The Firearms Blog and Update.

HK’s IAR wins

Sept 21/10: Marine Corps Times quotes MARSYSCOM’s IAR project officer, Maj. John Smith, the IAR project officer. He says that testing is complete, and:

“I’m on schedule to have a decision on the program to move forward. Maybe within three weeks or so, there will be a lot more information… Smith acknowledged that Commandant Gen. James Conway has questioned how the IAR will fit into fire teams but said that concern was “answered in short order.”

IAR candidate reliability testing reportedly took place in April and May at Marine Corps Base Quantico firing 20,000 rounds per weapon over 3 weeks. The Corps also reportedly held limited user evaluations for about 3 weeks in April in Hawthorne, NV, using Marines from Camp Pendleton, CA.

Dec 22/08: Under the initial contracts issued by US Marine Corps systems command in Quantico, VA, the winning competitors will supply up to 10 samples of their IAR design for testing, plus spare/repair parts, and various support services. The USMC will select a winner at some point, and plans to order up to 6,500 IARs via follow-on delivery orders, but there are no guarantees. Initial contracts, see also: Gannett’s Marine Corps Times | Defense Tech | Military.com | StrategyPage | The Firearm Blog.

Dec 22/08: Colt Defense, Inc. in West Hartford, CT received a 5-year indefinite-delivery/ indefinite-quantity contract with possible delivery orders up to $14 million for the production, delivery, and associated support of the Marine Corps’ Infantry Automatic Rifle (IAR). Colt’s production facility is in West Hartford, CT (RFP M67854-08-R-1000, proposal 6940, contract number M67854-09-D-1035).

Dec 22/08: Colt Defense, Inc. in West Hartford, CT received a 5-year indefinite-delivery/ indefinite-quantity contract with possible delivery orders up to $14 million for the production, delivery, and associated support of the Marine Corps’ Infantry Automatic Rifle (IAR). Colt’s production facility is in West Hartford, CT (RFP M67854-08-R-1000, proposal 6940H, contract number M67854-09-D-1036).

Dec 22/08: FN Herstal, S.A. in Herstal, Belgium receives a 5-year indefinite-delivery/ indefinite-quantity contract with possible delivery orders up to $27.9 million for the production, delivery, and associated support of the Marine Corps’ Infantry Automatic Rifle (IAR). FN Herstal’s production facility is in Herstal, Belgium (M67854-09-D-1037).

Dec 22/08: Heckler and Koch Defense, Inc. in Ashburn, VA received 5-year indefinite-delivery/ indefinite-quantity contract with possible delivery orders up to $23.6 million for the production, delivery, and associated support of the Marine Corps’ Infantry Automatic Rifle (IAR). Work will be performed in Oberndorf, Germany. (M67854-09-D-1038).

Competitor contracts

Additional Readings

* FedBizOpps (2005) – Initial IAR solicitation

* Modern Firearms – Heckler-Koch HK M27 IAR Infantry Automatic Rifle (USA / Germany)

* Gary K. Roberts, LCDR, USNR at NDIA 2008 conference – Time for a Change [PDF format]. LCDR Roberts offers a history of US military small arms programs, as well as testing results from the 2007 multi-agency M4A1/MK12 Modified Upper Receiver Group (MURG) project. Includes evaluations of 6.8mm and 7.62mm caliber performance.

* Winds of Change – Taking Back the Infantry Half-Kilometer. Links to official report re: the need for lethality at range in Afghanistan, and related materials.

* Military.com (June 25/10) – Spec Ops Command Cancels New Rifle. It is a blow to FN Herstal, whose SCAR lost the USMC IAR and the British 7.62mm L129 competition.

* NY Times At War: Notes from the Front Lines (April 2/10) – The Weakness of Taliban Marksmanship. And how they make it work for them anyway. Effective, accurate counterfire at range offers an especial advantage against such opponents.

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