The King Arms Colt M4 Gas Blowback Rifle offers the airsoft player a more realistic alternative to an AEG. Every time the gun is shot, the bolt cycles just like the real thing. Bolt locks back when mag is empty. The rate of fire can be adjusted by changing the stock tube buffers.

Velocity can be adjusted by replacing the "valve blocker". A high power valve blocker is installed by default, which gives you between 420-450 fps with 0.20g BBs. With the (included) low power valve blocker the fps is reduced to between 320-350 fps with 0.20g BBs. The velocities we measured were by using green gas. Although HFC134a can be used, we do not recommend it due to cycling issues.