Own a piece of firearm history from the makers of the world’s most battle-proven firearms. The FN 15® Military Collector Series M4 brings to market a military replica rifle made to FN’s, and the U.S. military’s exacting specifications. The semi-automatic rifle is chambered in 5.56x45mm NATO and features a 14.7 inch barrel with permanently attached compensator (16″ overall length). The barrel is button-broached, has a 1:7 RH twist and is chrome-lined. The UID-labeled lower receiver is equipped with an ambidextrous selector switch, just like its select-fire big brother, the M4A1.