M27 Infantry Automatic Rifle

M27 Infantry Automatic Rifle
A U.S. Marine armed with an M27 IAR affixed with ACOG Squad Day Optic.
Type	Squad automatic weapon Assault rifle Designated marksman rifle
Place of origin	Germany
Service history
In service	2010–present
Used by	United States Marine Corps
Wars	Operation Enduring Freedom
Production history
Designer	Heckler & Koch
Designed	2008
Manufacturer	Heckler & Koch
Unit cost	US$3,000
Produced	2010–present
Number built	4,153
Specifications
Weight	7.9 lb (3.6 kg) empty
Length	36.9 to 33 in (940 to 840 mm) w/ adjustable
Barrel length	16.5 in (420 mm)
Width	3.1 in (79 mm)
Height	9.4 in (240 mm)
Cartridge	5.56×45mm NATO
Action	Gas-operated short-stroke piston, rotating bolt
Rate of fire	Sustained: 36 rpm Cyclic: 700 to 850 rpm
Effective firing range	550 m (point target) 800 m (area target)
Maximum firing range	3,938 yd (3,601 m)
Feed system	30-round STANAG magazine
Sights	3.5x Squad Day Optic, flip-up rear rotary diopter sight and front post

The M27 Infantry Automatic Rifle (IAR) is a lightweight, magazine-fed 5.56mm weapon used by the United States Marine Corps. It is intended to enhance an automatic rifleman's maneuverability, and it is based on the Heckler & Koch HK416. The U.S. Marine Corps is planning to purchase 6,500 M27s to replace a portion of the M249 light machine guns currently employed by automatic riflemen within Infantry and Light Armored Reconnaissance Battalions. Approximately 8,000–10,000 M249s will remain in service at the company level to be used at the discretion of company commanders. The United States Army does not plan to purchase the IAR.

In 1985, the U.S. Marine Corps adopted the M249 Squad Automatic Weapon, one year after the U.S. Army. Procurement was a service-level decision because the weapon was adopted by the Army with a contract method the Marines could use. While the belt-fed M249 was portable and had a high volume of fire, it was heavy for its role. Gunners could not keep pace with riflemen and the cumbersome light machine gun was not suited for Military Operations on Urban Terrain.

In 1999, a Universal Need Statement was issued for an Infantry Automatic Rifle (IAR). Around 2000, the 1st Marine Division’s 2nd Battalion, 7th Marines Regiment conducted initial, limited IAR trials which confirmed the desirability of a light automatic rifle. Experiences in Iraq and Afghanistan resulted in formal requests for recommendations. The Universal Need Statement spent six years going through the procurement process before an official program was begun and a list of required capabilities was created in early 2005.