This fully licensed gas blowback Colt M4 by King Arms is an excellent option for anyone looking for an affordable, high quality gas blowback rifle. The rifle features a full metal RIS and an adjustable LE style stock. The gas system is designed by GHK and is fully interchangeable with a version 2 AEG gearbox. The upper and lower receiver are made of durable, lightweight nylon fiber. The lower receiver is engraved with the official Colt trademark and proudly states "PROPERTY OF U.S. GOVT M4A1 CARBINE CAL 6MM." This airsoft gun is powered by green gas. The gas gives the gun instantaneous trigger response and a much more realistic blowback action than what an EBBR is able to produce. The gun fires in either semi or full auto mode. The magazine capacity is 40 rounds. Features: