First Look: SIG Sauer MCX-Rattler LT

The modularity starts with two different models and three different calibers and goes up from there.

posted on November 21, 2023
SIG Sauer MCX-Rattler LT

The SIG Sauer MCX Rattler platform was originally created to meet the demands of the US Special Operations community, including the ability to tailor the configuration of the gun to mission-specific requirements. Now all the breakthrough features of the original MCX-Rattler are available in a more modular and capable package. The MCX-Rattler LT is available in three different calibers (300 BLK, 5.56 NATO or 7.62x39 mm), in either a large format pistol or short-barreled rifle (SBR) version. All these models feature fully ambidextrous controls, including an ambidextrous bolt-catch, bolt-release an adjustable gas piston for suppressed and unsuppressed use, and are fitted with the SIG QD suppressor-ready flash-hider and a flat-blade trigger for precise control. The MCX-Rattler LT with either a 6- or 7.75-inch long, cold-hammer-forged barrel that is fully compatible with all MCX barrels and handguards, creating a modular firearm you can easily upgrade. The overall length of the MCX Rattler varies from 16.5 inches to 25.75 inches depending on the barrel length, and the collapsed length of the SBR version ranges from 17 to 18.25 inches.  

MCX-Rattler LT Features

  • 6.75- or 7.75-inch cold-hammer-forged barrel
  • Available in large format or SBR configuration
  • Fully ambidextrous controls
  • Interchangeable barrels that are compatible with all LT barrels and handguards
  • SIG Flatblade match trigger
  • SIG SLX/SLH suppressor-ready flash hider

MCX-Rattler LT Specifications

  • Caliber: .300BLK, 5.56 NATO or 7.62x39mm
  • Magazines Included: One 30-round magazine
  • Action Type: Semi-automatic
  • Barrel Material: Cold-hammer-forged carbon steel
  • Trigger Type: 2-Stage match
  • Twist Rate: 1:5 (.300 BLK), 1:7 (5.56 NATO), 1:9.5 (7.62x39mm)
  • Overall Length: 16.5 to 25.75 inches, depended on barrel length
  • Collapsed Length: Varies by model
  • Overall Width: 2.25 inches
  • Height: 7.4 inches
  • Accessory Rail: Picatinny
  • Operating System: Short-stroke piston
  • Weight: Varies by model

For more information on the new MCX-Rattler LT or other products from SIG Sauer, please visit


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