The Daniel Defense M4A1 Upper Receiver Group in FDE (brand part no. 23-004-13150) brings the same M4A1 Rail Interface System used by SOCOM’s SOPMOD II program to a complete, drop-on upper chambered in .223 Rem/5.56 NATO. Daniel Defense builds this two-piece, free-floating rail around a 14.5-inch cold hammer forged M4-profile barrel with a permanently attached flash suppressor pinned and welded to meet the NFA’s 16-inch minimum rifle length, so the assembly ships and installs as a standard Title I rifle upper rather than a regulated item. The bolt-up rail system uses six grade-8 bolts to fully support any mounted accessories while keeping the barrel completely free-floating for accuracy, and the two-piece design allows partial rail removal for cleaning without a full teardown. It comes standard with an M16-profile bolt carrier group and no sights, ready to drop onto a compatible AR-15 lower.

Key Specifications

• Chambered in .223 Rem/5.56 NATO for broad ammunition compatibility.
• Built with a 14.5-inch cold hammer forged barrel, pinned and welded to a 16-inch overall length.
• Rifled at a 1-in-7-inch twist rate suited to a wide range of 5.56 bullet weights.
• Uses the M4A1 RIS II two-piece, free-floating rail system as fielded by SOCOM.
• Includes a standard M16-profile bolt carrier group ready to install.
• Finished in FDE for a coyote/tan colorway.
• Ships with no sights installed, ready for the buyer’s optic of choice.
• Sold as a complete upper assembly rather than individual barrel and rail components.
• Uses a two-piece rail design that allows partial removal for cleaning.

Frequently Asked Questions

Is this a complete upper or a barrel only? It’s a complete upper receiver group, including barrel, RIS II rail, and M16-profile bolt carrier group, ready to install on a compatible lower.

Why is the barrel 14.5 inches instead of 16? Daniel Defense permanently attaches a flash suppressor to bring the total barrel-plus-device length to 16 inches, satisfying the NFA’s minimum rifle barrel length while keeping the bare barrel shorter and lighter.

Does it include iron sights? No, it ships with no sights so the buyer can add optics or irons to their own preference.

Buy the Daniel Defense M4A1 Upper Receiver Group

Upgrade to a battle-proven rail system with this Daniel Defense upper from our AR15 uppers lineup. Order it from our Lubbock, Texas gun shop for fast, insured shipping to your FFL.