IAR What IAR: The USMC’s SAW Substitution

06-Jul-2010 17:41 EDT


HK wins; Commandant skeptical, but authorizes limited buy and combat test. (July 1/10)

The US Marines are looking to replace their M249 5.56mm light machine guns in their infantry and Light Armored Reconnaissance (LAR) battalions. Many have become worn from use, and can be more hindrance than help in some of the close-quarters urban warfare situations dominating current battlefields. They also have a reputation for jamming, and at 15-17 pounds empty, these belt-fed weapons are rather heavy.

In its initial 2005 FedBizOps.com solicitation for an “Infantry Automatic Rifle” (IAR), the Marines 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 also 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.

* The Contenders
* IAR What IAR: The Choice [updated]
* Contracts and Key Events [updated]
* Additional Readings [updated]

The Contenders
Colt CAR
Colt LSW/CAR


The winning bids went to a set of long-established competitors.

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 is not yet clear if this represents CAR and IAR awards, or if the twin contracts have a different set of dual competitors. Regardless, neither won.
SCAR-IAR
SCAR-IAR


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 is entering a version of the SCAR Mk16 rifle that has 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. Since the Marines plan to rotate personnel back to regular Marine units after MARSOC, a rifle that’s shared with SOCOM offers 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 fielded an extended SCAR-H Mk.20 with sharpshooter enhancements.
HK416 Labeled
HK416, labeled
(click to view full)

Heckler & Koch. 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 design won.

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