User blog comment:JoeRamirez/Call of Duty Modern Warfare 3 Weapons Wishlist./@comment-69.108.138.0-20110407015241/@comment-908633-20110408041737

Maybe you should check Wikipedia. This is from the first sentence on the M16 page: "The M16 (more formally Rifle, Caliber 5.56 mm, M16) is the United States military designation for the AR-15 rifle."