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Heckler & Koch HK M27 IAR (Infantry Automatic Rifle)

2011 MODERN

History of Heckler & Koch HK M27 IAR (Infantry Automatic Rifle)

Adopted by the U.S. Army and used by many other ground combat forces around the world, the HK416 AR-15-based automatic rifle manufactured by Heckler & Koch in Germany also forms the basis for the new U.S. Marine Corps (USMC) M27" Infantry - Automatic Rifle" (IAR).

Introduced in 2011, the product has since been in frontline combat service in the Afghanistan theater, where it has been used to replace some of the larger, heavier, belt-fed M249 SAW (Squad Automatic Weapon)/Light Machine Gun (LMG) . The M27 offers a lighter and more convenient form of automatic fire while holding the same 5.56x45mm NATO cartridge and feeding from a detachable magazine. Currently, thousands of M27s make up USMC's inventory.

Based on recent experience in Iraq and Afghanistan, Marine Corps infantry units found a need for a lighter weight alternative to the unwieldy, less accurate M249 system, especially when operating in confined urban environments. In 2005, a program was launched to find a weapon that would meet the needs of a medium automatic weapon that could be fed from a 100-round 5.56x45mm NATO caliber cartridge. Eventually, the 100-round requirement was reduced to the standard 30-round detachable magazine, and several gun suppliers were contracted to test samples.

Finally, the German Heckler & Koch HK 416 was declared the winner in 2009, and the weapon was adopted by the US Marine Corps in 2010 as the "M27".

The initial field acceptance of the M27 against the tried-and-true M249 was slow as a handful of new weapons entered active theater. Thanks to the M27's selective fire capability (a feature that the M249 lacked), this new weapon allows for variable rate of fire and accuracy across the range, while competing with existing infantry-grade weapons such as the M16A4 assault rifle and M4-carbine ) share some parts commonality (the M27 supports the basic 30-round STANAG arc magazine). Additionally, the functionality and versatility of the M27 allows it to be used in the Designated Marksman Role (DMR), which cannot be achieved with the M249, which is primarily a fire fighting weapon. Troops also appreciate the lighter payload of their new weapon, especially on long marches.

To compensate for the difference in ammo counts between the belt-mounted M249 and the magazine-mounted M27, the magazine supply was allocated to marching members up to 22 30-round magazines, which corresponded to a typical ammo-loaded M249 portion (approximately 600 rounds in total).

Since the HK 416 is the basis for the M27, its overall design and functionality go hand in hand. This includes the Picatinny rail section for mounting various tactical accessories, including optical accessories and handles. The air mechanism uses a short stroke piston with a pivot pin. The free-floating barrel helps maintain accuracy throughout the range.

A folding bipod can be used to support the front of the rifle when fighting fires. Dimensions include 37" overall length and 16.5" barrel. The adjustable stock reduces the length to a more manageable 33 inches. Curb weight is 8 lbs.

The internal structure of the gun allows a rate of fire of 700 to 850 rounds per minute. The effective range against specific targets is up to 550 meters, while the general area is up to 3,600 meters. Aiming is usually via a standard 3.5x Squad Day optical fit.

The flip-up rear rotating diopter sight is attached to the front post of a traditional "iron" sight, essentially acting as a backup for the optics.

Due to the established characteristics of the M249, the M27 is not a direct replacement for the fabled light machine gun - at least not yet - as soldiers gain more experience in the same role with newer, lighter automatic rifles .

The M38 is the Designated Marksman (DM) form of the M27 being tested by the US Marine Corps. This model comes with a 16.5" barrel that holds the same 5.56mm cartridge as the HK 416 series. Optics are different from DM reels.