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Questions & Answers
Any reason this would not be compatible with my Ambush Series DDM4 in 300blk? It originally shipped with the 16" heavy barrel.

I can answer my own question here after calling DD. 100% compatible. Just slap it on. It's mil-spec.

by kevin, Verified Owner, November 14, 2024
Hi is the barrel threaded? Expert Answer

Yes. The Daniel Defense DDM4 300 S, URG, 10.3in, 300 AAC Blackout Complete Upper Receiver is threaded 5/8x24 and includes a removable flash hider.

by Ethan, Gear Expert, June 17, 2022
Customer Reviews
Helpful Positive Review 300 Black that just works - Supers and Subs by clickhouse, Verified Owner, July 18, 2024
This is a great deal. This is a very high-quality DD SOCOM-MK18 upper chambered in 300 Blackout. A MK 18 retails from DD for $2,200. The math is simple: pair this with a very high quality lower and use the savings to buy ammo. It is heavy because of...
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1/2 found this helpful
Helpful Positive Review DDM4 300S 10.3 Upper Receiver group by Rob, Verified Owner, July 7, 2024
It's a MK18 in .300BLK, product was obviously perfect because Daniel Defense QC is among the best in the business. If you want a very reliable and durable shorty upper in .300BLK, there are not many options better than this.
1/1 found this helpful
Helpful Positive Review DD 300 BO upper by J, January 18, 2024
Quality Quality Quality. Thank you Palmetto State Armory for another sweet deal!
1/5 found this helpful
Helpful Positive Review amazing price by king, Verified Owner, August 21, 2024
Amazing price. Can’t beat a DD upper for the name and quality for the price. Will be buying from here in the future.
1/2 found this helpful
Helpful Positive Review Good purchase by CF, Verified Owner, November 23, 2024
Great upper. All the quality you expect from Daniel Defense, a little pricey but you get what you pay for. Optics planet offers a decent discount on it if you are patient.
1/1 found this helpful
Helpful Positive Review DD is the best by Rickshaw, March 19, 2020
I love Daniel Defense products and customer service. Would recommend to anyone looking for a quality AR-15, and parts. There a quality product produced in the good ole USA. Now they want this review to 200 words so this sentence should be sufficie...
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5/5 found this helpful
Read All 16 Reviews
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Product Info for Daniel Defense DDM4 300 S, URG, 10.3in, 300 AAC Blackout Complete Upper Receiver w/ Flash Hider

The Daniel Defense M4 300S Upper Receiver Group w/ Flash Hider comes equipped with a rugged, cold-hammer-forged 10.3-inch barrel with a Strength-to-Weight profile. Daniel Defense produces these AR15 Upper Receivers for those who crave a high-performance, short-barrel rifle in 300BLK caliber. Each Daniel Defense M4 300S Upper Receiver Group comes with a flash suppressor and a low-profile pistol length gas system that provides smooth operation and reduces felt recoil. A DDM4 Rail 9.0 handguard allows room for accessories and has 3 comfortable Santoprene panels that are heat resistant up to 300 degrees to protect you from the hot barrel and gasses. Treat yourself and your platform to the Daniel Defense M4 300S Complete Upper Receiver Group w/10.3in 300BLK Barrel.image

Specifications for Daniel Defense DDM4 300 S, URG, 10.3in, 300 AAC Blackout Complete Upper Receiver w/ Flash Hider:

Manufacturer: Daniel Defense
Caliber: .300 AAC Blackout
Finish: Matte
Color: Black
Gun Model: M4
Magazine Included: No

Features of Daniel Defense M4 300S, Upper Receiver Group, 10.3in, 300 AAC Blackout Barrel, Flash Hider 23-088-19020-047:

  • Mil-Spec upper receiver with indexing marks and M4 feed ramps. CNC machined of 7075-T6 Aluminum with Type III hard-coat anodized finish.
  • Chrome Moly Vanadium Steel 10.3-inch barrel is cold hammer forged with 1:8 twist, S2W (Strength-to-Weight) profile, pistol length gas system, chrome lined, MP tested, and Mil-Spec heavy phosphate coated.
  • Gas system is pinned low profile gas block CNC machined of 4140 hardened steel with Mil-Spec heavy phosphate coating. Pistol length. Direct impingement.
  • Daniel Defense Flash Suppressor of 17-4 PH stainless steel with salt bath nitride finish.
  • Bolt Carrier Group: M16 Profile, Mil-Spec MP tested, chrome lined, properly staked gas key.
  • Daniel Defense DDM4 Rail 9.0, CNC machined from 6061-T6 aluminum with Type III hard-coat anodized finish.
  • Daniel Defense Vertical Grip made of glass-filled polymer with soft-touch overmolding.

Package Contents:

  • Daniel Defense M4 300S, Upper Receiver Group, Flash Hider, 10.3in 300BLK Barrel 23-088-19020-047

Daniel Defense DDM4 300 S, URG, 10.3in, 300 AAC Blackout Complete Upper Receiver w/ Flash Hider Orderable Models

List of Orderable Models

USED, Daniel Defense DDM4 300 S, URG, 300 AAC Blackout, 1/8, S2W, LPG, DDM4 Rail 9.0, DDFS Complete Upper Receiver w/ Flash Hider, Black, 10.3in, 23-088-19020-047 , MPN: 23-088-19020-047-EDEMO , Code: DDD-UFH-DDM4Q-23-088-19020-047-EDEMO-RE-C
Daniel Defense DDM4 300 S, URG, 300 AAC Blackout, 1/8, S2W, LPG, DDM4 Rail 9.0, DDFS Complete Upper Receiver w/ Flash Hider, Black, 10.3in, 23-088-19020-047 , MPN: 23-088-19020-047 , UPC: 815604015134 , Code: DDD-UFH-DDM4Q-23-088-19020-047

Daniel Defense DDM4 300 S, URG, 10.3in, 300 AAC Blackout Complete Upper Receiver w/ Flash Hider Unavailable & Discontinued Models

List of Unorderable Models

DEMO, Daniel Defense DDM4 300 S, URG, 300 AAC Blackout, 1/8, S2W, LPG, DDM4 Rail 9.0, DDFS Complete Upper Receiver w/ Flash Hider, Black, 10.3in, 23-088-19020-047 , MPN: 23-088-19020-047-DEMO , Code: DDD-UFH-DDM4Q-23-088-19020-047-DEMO
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