M27 Infantry Automatic Rifle Review

The M27 Automatic Rifle is a 5.56mmx45mm rifle that used by Marine Corps forces. The M27 will replace many of the M249 SAW belt-fed light machine guns currently employed at the squad level.

The M27 is based on the Heckler & Koch HK416 D16.5RS . Delta Force reportedly both use the HK416 as an assault rifle/carbine. The USMC use  the M27 as a designated automatic rifleman’s weapon i.e. to provide suppressing fire as part of a 4-man fire team.

Previous doctrine was to use the M249 SAW in the suppressing fire role. The M249 had a much higher rate of fire and was fed from higher capacity magazines compared to the M27. The commonly held wisdom was that the high rate of fire would keep the enemy’s head down, even if round placement was relatively inaccurate, especially at longer ranges. This doctrine has now been updated to favor a more accurate, slower firing weapon that suppresses the enemy through rapid, well-aimed fire, an approach thought to be more effective against seasoned enemy troops.

Weighing in at 9lb (loaded) compared to the 22lb (loaded) for the M249 SAW, the M27 is light enough to allow its operator to keep up with the rest of his fire team / squad, something that was an issue for SAW gunners. The M27 is also easier to handle in close quarters combat environments and a M27 gunner can easily transition from laying down suppression fire to clearing a building.

Picatinny rails surround the M27’s free-floating 16.5inch barrel on which a number of accessories come fitted as standard. A Harris fold-down bipod provides stability in the suppression role while a fore grip allows for better handling in CQB scenarios. The standard scope for the M27 is the SU-258/PVQ Squad Day Optic.

Magazines are 30 round magazine, which are interchangeable with the M16 and M4 magazines carried by the rest of a fire team. Large capacity magazines, in the 50-100 round range, are being considered to enable more sustained fire between reloads.

M27 IAR Specifications

weight: 7.19 lbs (empty)
9 lbs (loaded with 30-round magazine)
length: 36.9 inches (stock extended fully)
33 inches (stock retracted)
barrel length : 16.5 inches
action : Gas-operated short-stroke piston, rotating bolt
rate of fire : Sustained: 36 rpm
Cyclic: 700 to 850 rpm
muzzle velocity : 2,550 feet per second
effective range : 550 meters (point target)
600 meters (area target)
caliber : 5.56x45mm NATO
magazine : 30-round STANAG magazine