Daniel Defense M4A1 Upper Receiver, 223 Remington/5.56 NATO, 14.5″ Barrel (16″ OAL with Pinned Brake)

Product Description

The Daniel Defense M4A1 Upper Receiver is built to the exact specifications of the carbine issued to U.S. military units worldwide. This complete upper features a 14.5″ cold hammer forged barrel paired with Daniel Defense’s signature flash suppressor, permanently pinned and welded to achieve 16″ overall length. The result is a non-NFA configuration that pairs seamlessly with any standard rifle lower receiver.

Every Daniel Defense upper is hand assembled, quality assurance tested, and test fired before shipment. The 5.56 NATO caliber delivers proven accuracy and reliability across military and civilian platforms alike. The RIS II 12.0 rail system gives you M-LOK and Picatinny mounting options for optics, lights, and accessories without compromise.

Additionally, the GRIP-N-RIP ambidextrous charging handle and M16-profile bolt carrier group ensure smooth operation in any shooting position. Carbine-length gas tuning balances reliability with manageable recoil. This is a no-compromise upper for shooters who demand military-grade performance.

Built for Serious Shooters

Whether you’re building a patrol carbine or upgrading an existing lower receiver, this upper integrates with standard AR platform components. Furthermore, the pinned-and-welded flash suppressor eliminates any NFA compliance questions—it ships and functions as a complete, legal rifle upper from day one.

Materials & Construction

• Upper Receiver: Mil-Spec with Indexing Marks and M4 Feed Ramps, CNC Machined of 7075-T6 Aluminum, Type III Hard Coat Anodized
• Barrel: 14.5″ M4 Profile, Chrome Moly Vanadium Steel, Cold Hammer Forged, 1:7 Twist, Chrome Lined, Mil-Spec Heavy Phosphate Coated, HP/MPI Tested — with a Daniel Defense Flash Suppressor permanently pinned and welded to bring total barrel length to 16″, a non-NFA configuration that requires no tax stamp
• Gas System: Pinned Low-Profile Gas Block, CNC Machined of 4140 Hardened Steel, Mil-Spec Heavy Phosphate Coating, Carbine-Length, Direct Impingement
• Muzzle Device: Daniel Defense Flash Suppressor, 17-4 PH Stainless Steel, Salt Bath Nitride Finished, Permanently Pinned and Welded to the 14.5″ Barrel for a 16″ Overall Length
• Handguard: Daniel Defense RIS II 12.0, Free-Float Quad Rail, CNC Machined of 6061-T6 Aluminum, Type III Hard Coat Anodized, Continuous MIL-STD-1913 Picatinny Rails at the 12, 3, 6 and 9 o’clock Positions, 6-Bolt Bolt-Up System
• Bolt Carrier Group: M16 Profile Bolt Carrier Group, Mil-Spec MP Tested, Chrome Lined, with Properly Staked Gas Key
• Charging Handle: Daniel Defense GRIP-N-RIP Charging Handle — Body CNC Machined of 7075-T6 Aluminum, Handles & Latch CNC Machined of 6061-T6 Aluminum, Heavy Duty Stainless Steel Roll Pins, Type III Hard Coat Anodized
• Rail Panels: Daniel Defense Rail Panels, Santoprene, Heat Resistant to 300°F

Specifications

Although the bare barrel measures 14.5 inches, Daniel Defense permanently pins and welds the flash suppressor to the muzzle, bringing the total barrel length to 16 inches. This is a non-NFA configuration — no ATF Form 1 or Form 4 is required for this upper as configured.

Why Buy from Western Sport?

• Western Sport’s knowledgeable staff can answer caliber-specific and compatibility questions on the spot.
• We offer competitive pricing on all Daniel Defense uppers, with volume discounts available.
• Every upper is verified in stock and ships quickly to get your build started sooner.
• Our after-sale support includes recommendations for matched lower receivers and accessories tailored to your mission.
• We stand behind every product with straightforward returns and a commitment to your shooting success.

Frequently Asked Questions

Q: What ammunition performs best in the 5.56 NATO chamber of this upper?

A: This upper is chambered in 5.56 NATO, which accepts both 5.56 NATO and .223 Remington ammunition. However, 5.56 NATO is optimized for this military-spec upper and delivers superior performance in the cold hammer forged barrel. Additionally, military-grade 5.56 rounds tend to offer consistency and reliability across various shooting conditions.

Q: What lower receivers and mil-spec parts will work with this upper?

A: This upper is built to standard AR-15 dimensions and mates with any mil-spec rifle lower receiver. Furthermore, it accepts standard M16-profile bolt carrier groups and charging handles. All common AR furniture, buffers, and springs are fully compatible with no modifications required.

Q: How does the RIS II 12.0 rail compare to other Daniel Defense handguard options?

A: The RIS II 12.0 is Daniel Defense’s proven modular rail system offering both M-LOK and Picatinny slots for maximum mounting flexibility. This configuration balances weight, durability, and accessory compatibility. Additionally, the RIS II name is recognized by mil-spec builders and tactical professionals worldwide.

Q: What comes included with this complete upper receiver group, and what does it ship as?

A: This is a complete upper—it arrives fully assembled and test fired, ready to mate with any rifle lower receiver. Additionally, no further assembly or gunsmithing is required. However, you will need to source your own lower receiver, buffer system, and stock to complete the rifle.

Q: What is the RIS II rail system on this upper?

A: The RIS II (Rail Interface System II) is Daniel Defense’s free-float quad-rail handguard, originally developed for USSOCOM’s SOPMOD II program. It carries continuous MIL-STD-1913 Picatinny rails at the 12, 3, 6, and 9 o’clock positions, so lights, lasers, foregrips, iron sights, and optics all mount directly without adapters. Additionally, a 6-bolt bolt-up system locks the rail to the upper receiver for a repeatable zero.

Q: Do I need NFA paperwork for this upper?

A: No. Although the bare barrel measures under 16 inches, Daniel Defense permanently pins and welds the flash suppressor to reach a full 16 inches. As a result, this upper is a non-NFA configuration and requires no Form 1 or Form 4.

Additional information