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Sig Sauer M400-FORGE 5.56 NATO Semi-Auto Rifle with ROMEO-MSR Gen II Red Dot

  • Item Number: RM400-556N-16B-FORGE
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  • View More Items by Sig Sauer
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  • Condition: NEW
Sig Sauer M400-FORGE 5.56 NATO Semi-Auto Rifle with ROMEO-MSR Gen II Red Dot
SIG SAUER M400-FORGE 5.56 NATO Semi-Auto Rifle with ROMEO-MSR Gen II Red Dot
SIG SAUER M400-FORGE 5.56 NATO Semi-Auto Rifle with ROMEO-MSR Gen II Red Dot
SIG SAUER M400-FORGE 5.56 NATO Semi-Auto Rifle with ROMEO-MSR Gen II Red Dot
SIG SAUER M400-FORGE 5.56 NATO Semi-Auto Rifle with ROMEO-MSR Gen II Red Dot
SIG SAUER M400-FORGE 5.56 NATO Semi-Auto Rifle with ROMEO-MSR Gen II Red Dot
$999.99 $1,099.99

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Product Description

What's in the Box

  • SIG M400-FORGE 5.56 NATO Semi-Auto Rifle
  • (1) 30-Round Magazine
  • SIG ROMEO-MSR Gen II Red-Dot Sight
  • Cable Lock
  • Owner's Manual

The SIG SAUER M400-FORGE is a modern 5.56 NATO rifle engineered for shooters who demand reliability, precision, and performance. Built around a 16" cold hammer forged barrel and mid-length gas system, the M400-FORGE delivers exceptional durability and smooth, consistent operation in any environment.

Upgraded where it matters. Ready from day one.

At the heart of the rifle is a TriggerTech 3.5 lb two-stage flat blade duty trigger, delivering the kind of crisp, predictable break shooters typically upgrade to. Paired with the included ROMEO-MSR Gen II red dot optic, the M400-FORGE provides fast target acquisition and confident shooting right out of the box.

A full-length free-floating M-LOK handguard, ambidextrous charging handle, and MAGPUL SL-K adjustable stock deliver modern ergonomics and adaptability for a wide range of applications.

Built by SIG SAUER, a brand trusted worldwide for performance and durability, the M400-FORGE is backed by the SIG Infinite Guarantee—our lifetime, fully transferable promise that stands behind every firearm we build.

The result is a rifle ready for the range, defense, and the mission ahead.

  • TriggerTech 3.5 pound two-stage flat blade duty trigger
  • 16" cold hammer forged barrel with mid-length gas system
  • ROMEO-MSR Gen II 2 MOA red dot included
  • Full-length free-floating M-LOK handguard
  • Ambidextrous charging handle
  • MAGPUL SL-K 6-Position adjustable stock

Firearm Specifications

  • Manufacturer Sig Sauer
  • Model M400-FORGE
  • SKU RM400-556N-16B-FORGE
  • Firearm Type Rifle
  • Caliber 5.56 NATO
  • Sights ROMEO-MSR GEN II w/ 2 MOA Dot
  • Barrel Length 16 in (406.4 mm)
  • Barrel Material Cold Hammer Forged Steel
  • Twist Rate 1:7
  • Thread Pattern 1/2"-28 90° Shouldered
  • Muzzle Device A2 Birdcage Flash Hider
  • Action Type Semi-Auto
  • Operating System Mid-Length Direct Impingement
  • Stock Type 6-Position Magpul SL-K
  • Grip Type Reduced Angle
  • Trigger Type TriggerTech 3.5 lb 2-Stage Flat Blade
  • Trigger Shape Flat
  • Manual Safety Ambidextrous
  • Forend Type M-LOK Black Anodized Alloy
  • Accessory Rail M-LOK / Full-Length Picatinny
  • Magazine Type AR-15
  • Magazines Included (1) 30 rd Polymer Mag
  • Color Black
  • Receiver Finish Black Anodized
  • Overall Length 35.5 in (901.7 mm)
  • Collapsed Length 32.25 in
  • Overall Width 2.7 in (68.58 mm)
  • Height 9.4 in
  • Weight 6.8 lb

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