Daniel Defense DD4 MK18 RIII SBR 5.56 NATO 10.3″

The Daniel Defense DD4 MK18 RIII is a short-barreled rifle (SBR) built around a 10.3″ cold hammer forged barrel and chambered for .223 REM/5.56 NATO. It uses a semi-automatic action and a mid-length gas system to balance recoil impulse and reliability. The lighter-weight RIS III M-LOK rail replaces the older RIS II system for modular accessory attachment, and the lower receiver is fully ambidextrous with a manual safety for versatile handling. The muzzle is threaded 1/2×28 to accept standard muzzle devices.

Key Specifications

• The rifle is chambered in .223 REM/5.56 NATO.
• The barrel measures 10.3″ and is cold hammer forged.
• The action is Semi-Auto.
• The rail system is a RIS III M-LOK Rail for accessory mounting.
• The gas system is a Mid-Length Gas System.
• The lower receiver is Fully Ambidextrous.
• The muzzle features a 1/2×28 thread pattern.
• The rifle ships with a Polymer stock.
• The published weight is 5.73 lbs.
• The barrel twist rate is 1-in-7.

Designed for compact tactical applications where maneuverability and reliability matter, the DD4 MK18 RIII combines a short, hard-hitting barrel with modern modular mounting and an ambidextrous control layout. Its combination of a cold hammer forged barrel, lightweight RIS III M-LOK system, and mid-length gas tuning makes it a well-rounded option for operators and experienced shooters seeking a high-quality, compact platform.

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