Description
The SIG Sauer MCX-Rattler LT 6.75" 300 Blackout Upper gives you the ability to transform any standard platform into the ultimate, ultra-compact personal defense weapon (PDW). Purpose-built for maximum concealment, maneuverability, and optimized suppression, this complete upper receiver assembly utilizes a short 6.75-inch cold hammer-forged barrel finished in stealthy black anodizing.
Designed to adapt flawlessly to any standard AR-15 lower receiver using the included stock conversion kit, this package delivers next-generation, short-stroke gas piston reliability in an incredibly tight footprint.
Special Operations Evolution and Modular Design
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Short-Stroke Gas Piston System: Keeps carbon fouling and intense heat forward at the gas block rather than venting back into the action. Your receiver runs cleaner and cooler, radically increasing part longevity.
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Adjustable Suppressor Gas Valve: Features a multi-position gas regulator explicitly optimized to handle the contrasting pressures of subsonic and supersonic 300 Blackout ammunition, ensuring flawless cycling under suppressors.
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Full Spear LT Compatibility: The updated Rattler LT shares modular cross-compatibility with the larger MCX Spear LT series, allowing you to easily swap handguards or barrels to change configurations or calibers in the future.
The Ultimate Quiet CQB Setup
The 6.75-inch barrel is highly regarded as the absolute standard for a discrete 300 Blackout platform. It keeps the firearm remarkably short and balanced, even when hosting a full-sized silencer. The muzzle is capped with SIG Sauer’s advanced QD flash hider, giving you a direct mount solution for SLX or SLH series suppressors. To ensure absolute reliability with heavy subsonic loads, the barrel features a fast 1:5 twist rate to maximize projectile stabilization out of a short bore.
Compact, Bufferless Integration
This comprehensive kit includes everything required to modernize a standard lower receiver into a premier folding weapon system. Because the dual-rod recoil system is fully self-contained inside the upper receiver, a traditional AR-15 buffer tube is no longer needed. The included 1913 vertical rail adapter enables your build to immediately accept low-profile, side-folding stocks or braces, creating a highly portable package that easily stores inside small packs or vehicle compartments.
