Complex sentence: The M27 Infantry Automatic Rifle (IAR) is a lightweight, magazine-fed 5.56mm weapon used by the United States Marine Corps, which is intended to enhance an automatic rifleman's maneuverability and displacement speed, based on the HK416.
Split into simpler sentences: 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 displacement speed, and it is based on the HK416.