The Heckler and Koch 416 assault rifle is arguably a step up from the M4 carbine. Outwardly similar to the M4 in appearance, internally the rifle uses a gas-piston operating system, not the direct-impingement system used by the M4. This allows the rifle to run cooler and require less cleaning of the upper receiver, although it does reportedly make the 416 slightly front heavy. While the M4 and HK416 both share the same ammunition magazines and 5.56-millimeter round, the 416 has a longer sixteen-inch barrel, imparting a slight increase in range and velocity to the German-made weapon. The 416 is designated the M27 Infantry Automatic Rifle in U.S. Marine Corps service, and is being issued to all Marine infantrymen.
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