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Daniel Defense

Daniel Defense DDM4 300 S Upper Receiver Group

10.3" .300 Blackout URG optimized for suppressed shooting with S2W barrel profile and 1:8 twist.

Quick Specs

Price
$1,452
Weight
3 lb 10.4 oz
Brand
Daniel Defense
Category
upper

Features

  • .300 AAC Blackout
  • 10.3" CHF S2W barrel
  • Pistol gas
  • DDM4 Rail 9.0" Picatinny
  • BCG & GRIP-N-RIP CH included

Capability Boosts

Suppression+3
CQB+2
Reliability+1

Recommended For

Outdoor Defense+4
Home Defense+3
Competition+2
Vehicle Operations+2
Range Training+2
Duty/Patrol

Compatibility Tags

family: ar-patterninterface: picatinny-topbarrel: ultra-compactcaliber: 300blk

Overview

The DDM4 300 S Upper Receiver Group is Daniel Defense's purpose-built .300 AAC Blackout platform, optimized for both suppressed and unsuppressed shooting. The 10.3" barrel features Daniel Defense's proprietary S2W (Strength-to-Weight) heavy profile, providing enhanced accuracy and heat dissipation while maintaining reasonable weight.

The 1:8 twist rate is specifically chosen to stabilize both supersonic and subsonic .300 Blackout ammunition effectively. Subsonic 220gr loads perform exceptionally well suppressed, while supersonic 110-125gr loads deliver rifle-like terminal performance at CQB distances. The pistol-length gas system ensures reliable cycling across the full spectrum of .300 Blackout ammunition.

The DDM4 Rail 9.0" handguard provides Picatinny rails for mounting accessories, with included Santoprene rail panels for heat protection and improved grip. Like all Daniel Defense uppers, this package includes the M16 profile bolt carrier group (MPI tested) and GRIP-N-RIP ambidextrous charging handle.

Key Features

  • Cold hammer forged 10.3" S2W barrel, chrome lined, HP/MPI tested
  • 1:8 twist optimized for subsonic and supersonic .300 BLK
  • Pistol-length gas system for reliable .300 BLK cycling
  • DDM4 Rail 9.0" handguard with Santoprene rail panels
  • M16 profile BCG, MPI tested with properly staked gas key
  • GRIP-N-RIP ambidextrous charging handle
  • Daniel Defense flash suppressor (5/8x24 threads)

Pros

  • +Optimized 1:8 twist for full .300 BLK ammunition spectrum
  • +S2W barrel profile balances accuracy and heat management
  • +Excellent suppressor host with proper gas tuning
  • +Complete package with BCG and charging handle
  • +Daniel Defense quality and warranty
  • +Standard AR-15 lower compatible

Cons

  • Premium pricing for .300 BLK upper
  • 10.3" barrel requires SBR or pistol configuration
  • Heavier S2W barrel adds weight vs. government profile
  • Quad rail style heavier than M-LOK alternatives
  • .300 BLK ammunition more expensive than 5.56 NATO

Detailed Specifications

caliber
.300 AAC Blackout
barrelLength
10.3"
barrelProfile
S2W (Strength-to-Weight) Heavy
barrelMaterial
Chrome Moly Vanadium Steel, Cold Hammer Forged
barrelFinish
Chrome Lined, Mil-Spec Heavy Phosphate
twist
1:8
gasSystem
Pistol Length, Direct Impingement
gasBlock
Pinned Low Profile, 4140 Steel, Phosphate
handguard
DDM4 Rail 9.0", 6061-T6 Aluminum, Picatinny
upperReceiver
7075-T6 Aluminum, Type III Hard Coat Anodized
bcg
M16 Profile, MPI Tested, Chrome Lined
chargingHandle
GRIP-N-RIP, 7075-T6 Aluminum, Ambidextrous
muzzleDevice
DD Flash Suppressor, 17-4 PH SS, Salt Bath Nitride
threadPitch
5/8x24
weight
3.65 lbs
madeIn
USA

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