We shoot the newest addition to the Leatherneck arsenal!

HK M27 IAR now adaopted as the replacement for the SAW; Explorer cases by Ameripack.

The Marines’ new Infantry Automatic Rifle (IAR) made by Heckler & Koch is being deployed to replace the M249 Squad Automatic Weapon (SAW) on Leatherneck fire teams.

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The IAR was selected in preference over the entries from companies including Colt Defense and FN. The IAR is designed to be a full-auto, 5.56mm NATO light automatic weapon able to use the same M16/M4 30-round magazine as any Marine rifleman.

The M27 with Trijicon SAW optic and Manta Rails.

In May 2010, the USMC announced the adoption of the HK IAR as the M27 Infantry Automatic Rifle and placed them with units in combat areas.

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The M27 has proven that it provides better firepower than the SAW without the steel links in belt-fed ammo that add bulk and weight for the gunner, make reloading a two-handed evolution and take the gun out of the fight to clear some stoppages. Is this just my opinion? No. These are facts passed to me at Quantico by Chris Wade, a Marine Corps Battalion Gunner, while I was knocking down targets with three-round bursts with the M27 at 500 meters—something that would have taken half a belt with a SAW. If the HK IAR makes a salty Marine Gunner happy, I am not going to argue the point.

Author shooting M27 with Battalion Gunner Chris Wade calling the shots.

The short-stroke gas piston HK IAR is similar in operation to the HK416 and weighs 7.9 pounds empty, with a 16.5-inch, free-floating barrel and a collapsible stock that extend the overall length of the weapon from 33 to 36.9 inches. The IAR has many of the standard features, controls and characteristics of the Eugene Stoner-designed AR-15/M16/M4, so operators can easily transition from their standard rifle or carbine to the IAR with minimal re-training. The closed-bolt IAR uses the Stoner seven-lug rotating bolt, ambidextrous safety/fire selector, last round bolt-hold-open device, rear charging handle and magazine release button on the right side of the magazine well.

Author placing short burst right on top of 500 M target – Photo by Matt Schrapp.

The IAR is fitted with four Mil-Std-1913 Picatinny rails for the standard Trijicon SAW optic, but it is capable of mounting any night or day, iron or optical sighting system. The Trijicon SAW optic has 3.5X magnification and slightly longer eye relief than Trijicon’s Rifle Combat Optic to help prevent getting a “scope eye” from the weapon’s larger recoil when used on full-auto.

The M27 on the range at Quantico MCB.

Video: Roberto Giudici

I found the M27 controllable with its comfortable and fully adjustable stock. The rugged Trijicon TA11 SAW optic made it really hard to miss on full-auto or with single shots that dropped targets at 300 to 500 meters like a precision rifle. The M27 has a higher rate of fire than the M4, so putting a high volume of fire downrange is easily accomplished. Overall, the M27 is an effective battle weapon, and since the squad machine gunner is always a primary target for bad guy snipers, having a light automatic weapon that looks just like an M4 might make that job a bit safer too!

Specifications: HK M27 IAR
Caliber: 5.56x45mm NATO
Barrel: 16.5 inches
OA Length: 33 to 36.9 inches
Weight: 7.9 pounds (empty)
Action: Gas piston-operated, rotating bolt
Capacity: All GI and most aftermarket AR magazines
Rate of Fire: 800 to 900 Rounds per Minute

Load Comments
  • hall

    As a grunt I can say I’ve played with this beautiful weapon system and it is a dream. Its concept is suppression threw accuracy not just sprayin lead but to be able to keep people suppress but sustained well place shots and it does an amazing job

  • Dave

    The sustained rate of fire is 36+rpm according to HK.

  • Andre’ M. Dall’au

    Russ, great question. I’ll find out the answer from either Chris Wade or H&K and have it in the upcoming article about the M27 IAR in Tactical Weapons. Between the higher reliability and rate of fire, the Marines note that the M27 actually does a better job of providing accurate automatic fire than the SAW without the stoppages and with better accuracy.

  • Russ

    The M1903, M1, M14, and M16 all have a sustained rate of fire of 12-15 rounds a minute. What is the sustained rate of fire for the M27? Just wondering.

  • Scotsman

    Interesting [emotionally-based] comments. I hope that readers will understand that M27 is perhaps the most extensively tested infantry weapon in service. This concept and the weapon, itself, have undergone testing since 1999. Mk48? ~24 lbs. M249? About the same. In ALL testing, M27 actually produced MORE effective fire on the enemy than M249. While M249 is an excellent machine gun, it is NOT an excellent Automatic Rifle for the Automatic Rifleman. The Marine Corps did not come to this decision through emotion (like the previous comments), by reliance on anecdotal nonsense, or through the illusion of “firepower” created by lots of noise from M249. It’s simply math and a decision based on empirical data.

  • JohnP

    Should’ve gone Mk48!

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  • Reliable weapon with nice Explorer cases

  • Danno

    In sustained fire this gun will not hold up. This is a big mistake! SAW is a fine proven weapon. All this is a full auto carbine folks.