Sig Sauer MCX Rattler LT 7.62x39mm 7.75" Barrel 28+1 Capacity

The Sig Sauer MCX Rattler LT delivers compact firepower in the proven 7.62x39mm cartridge, combining a short 7.75-inch barrel with a piston-driven operating system for reliable performance. This lightweight variant maintains the MCX platform's modularity while reducing weight through strategic material choices and design optimization.

What Makes This Different

Unlike direct impingement systems, the MCX Rattler LT uses an adjustable short-stroke gas piston that keeps fouling away from the bolt carrier group. The 7.62x39mm chambering provides superior ballistic performance compared to 5.56/.223 variants, delivering approximately 30% more kinetic energy at typical engagement distances. The lightweight construction reduces overall system weight by 10-15% compared to standard MCX models without sacrificing structural integrity.

Key Features

• Adjustable gas piston system with multiple settings for suppressed and unsuppressed use
• 7.75-inch cold hammer forged barrel with 1:10 twist rate optimized for 7.62x39mm
• M-LOK compatible aluminum handguard with integrated QD sling attachment points
• Quick detach suppressor-ready flash hider with standard 14x1 LH threads
• Flat-faced trigger assembly with crisp break and short reset
• Picatinny rail stock adapter accepts AR-15 compatible stocks and braces
• OEM polymer grip with storage compartment and aggressive texturing

The compact dimensions make this platform effective for close-quarters applications while maintaining accuracy potential out to 300 yards with appropriate ammunition. Law enforcement agencies report consistent cycling with both steel-cased and brass ammunition types. The piston system operates reliably in adverse conditions, cycling properly after exposure to sand, mud, and temperature extremes from -40°F to 140°F.

Technical Specs

• Caliber: 7.62x39mm
• Barrel Length: 7.75 inches
• Overall Length: 16.5 inches (with folded stock adapter)
• Weight: 5.1 pounds (unloaded, without stock)
• Magazine Capacity: 28+1 rounds
• Handguard: M-LOK aluminum, 6.75 inches
• Thread Pitch: 14x1 LH (metric)
• Finish: Black anodized aluminum and nitride steel
• Made in USA

This configuration represents the intersection of compact design and intermediate cartridge performance. The MCX Rattler LT addresses the demand for a lightweight, reliable platform that maintains effectiveness in a reduced-length package.