Daniel Defense 300S URG

Product Description

The Daniel Defense 300S URG is a complete upper receiver assembly chambered in .300 AAC Blackout. This configuration pairs a precisely tuned 10.3″ barrel with a pistol-length gas system designed to unlock the full potential of the .300 BLK cartridge. Whether you’re running supersonic or subsonic ammunition, the 1:8 twist stabilizes both loads reliably.

Additionally, every Daniel Defense upper is hand-assembled, rigorously quality-assurance tested, and test-fired before shipment. This upper is built for shooters who understand that .300 Blackout performs best when paired with a suppressor. The 10.3″ barrel length and optimized gas system give you efficiency and velocity that shorter barrels cannot match.

Furthermore, this complete URG arrives ready to mount onto a compatible lower receiver. You get the barrel, bolt carrier group, charging handle, and rail system as one cohesive unit. Western Sport’s team has the expertise to help you select the right lower and ensure your build complies with all applicable laws.

Performance Built Into Every Detail

The pistol-length gas tube and 10.3″ barrel work together to optimize dwell time and recoil impulse. This engineering makes a measurable difference in both sound signature and ballistic performance when suppressed.

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: 10.3″ S2W Profile, Chrome Moly Vanadium Steel, Cold Hammer Forged, 1:8 Twist, Chrome Lined, Mil-Spec Heavy Phosphate Coated
• Gas System: Pinned Low-Profile Gas Block, CNC Machined of 4140 Hardened Steel, Mil-Spec Heavy Phosphate Coating, Pistol-Length, Direct Impingement
• Muzzle Device: Daniel Defense Flash Suppressor, 17-4 PH Stainless Steel, Salt Bath Nitride Finished
• Handguard: Daniel Defense DDM4 Rail 9.0, Free-Float, M-LOK Attachment, CNC Machined of 6061-T6 Aluminum, Type III Hard Coat Anodized
• 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

This upper ships with a barrel measuring under 16 inches. Installing it on a rifle-configured AR-15 lower receiver would create a Short-Barreled Rifle (SBR), which is regulated under the National Firearms Act. Buyers who plan to build this into a rifle-configured firearm should first submit ATF Form 1 and obtain an approved tax stamp, or install it on a pistol-configured lower consistent with current ATF rules. Western Sport cannot advise on individual compliance — buyers are responsible for following all applicable federal and state law.

Why Buy from Western Sport?

• Western Sport combines local expertise with knowledgeable staff who understand Daniel Defense builds inside and out.
• Our team provides personal guidance on lower receiver selection, NFA compliance, and the complete assembly process.
• Competitive pricing on all Daniel Defense uppers, backed by our reputation in the shooting community.
• Dedicated after-sale support ensures your build runs flawlessly long after purchase.
• Same-day shipping available on in-stock complete upper receiver groups.

Frequently Asked Questions

Q: What ammunition does the Daniel Defense 300S URG shoot best?

A: The 1:8 twist rate is specifically tuned to stabilize both supersonic and subsonic .300 AAC Blackout loads. This upper truly shines with suppressed fire, where subsonic ammunition delivers hearing-safe performance without a baffle strike.

Q: What lower receivers are compatible with this upper?

A: This complete upper fits any mil-spec AR-15 lower receiver. However, the 10.3″ barrel length means installing it on a rifle-configured lower creates a Short-Barreled Rifle regulated by the NFA. Western Sport staff can discuss legal options including pistol-configured builds.

Q: Does Daniel Defense offer other .300 Blackout URG options?

A: The 300S URG is our featured Daniel Defense .300 Blackout complete upper in stock. If you need a different barrel length, rail system, or configuration, our team can help identify alternatives or special-order options tailored to your mission.

Q: What comes in the box with this complete upper receiver group?

A: The complete URG includes the barrel, bolt carrier group, charging handle, and rail system. You do not need to source additional components—simply pair it with a compatible lower receiver and you’re ready to build. Western Sport includes detailed assembly guidance with every purchase.

Q: Do I need NFA paperwork for this upper?

A: It depends on your lower receiver. Installing this upper on a pistol-configured lower with no stock keeps the build classified as a pistol. However, installing it on a rifle-configured lower, or adding a stock, creates a short-barreled rifle and requires an approved ATF Form 1 first.

Additional information