The Daniel Defense M4A1 rifle features the M4A1 RIS II, the same rail system used by the pros at USSOCOM for the SOPMOD II Weapon System. The Daniel Defense M4A1 is built on a carbine length direct impingement operating system with a low profile gas block. The barrel on the M4A1 is 14.5" long, the standard barrel length for an M4 rifle - but has a pinned and welded 1.5" muzzle device for an overall barrel length of 16" allowing it to comply with NFA regulations. The pistol grip of DDM4V11 rifle is a proprietary Daniel Defense design with soft touch over molding and the buttstock features the same soft touch over molding at contact areas. Features of the Daniel Defense M4A1 RifleCalifornia Compliant Free-Floated Cold Hammer Forged Barrel for long term durability and superior accuracyFull Length Top Rail for mounting optics of almost all sizesAmbidextrous Safety Selector Switch for left and right handed shooters Daniel Defense M4A1 5.56mm NATO 14.5" 1:7" Bbl CA Compliant Mil Spec+ Rifle 02-088-15126-055