Turn your ARX100 into a SBR. 5.56mm 10.25� Barrel Kit for your ARX100. This kit features a 10.25� cold hammer forged chrome lined barrel with an A2 flash hider. Complete with gas system for easy swap. This kit also includes a 30 RD steel magazine and nylon carrying case. NFA Rules Apply - NOTICE: Installing the 10.25� barrel into this firearm converts the firearm into a National Firearms Act Class III short-barreled rifle possession of which requires registration with the U.S. Bureau of Alcohol Tobacco Firearms and Explosives and payment of federal tax. Additional strict controls might be required by state law. Compliance with these restrictions is the responsibility of the owner of the firearm.