Sig Sauer 8901313 Barrel&Gas Block Assy Mcx 556 11.5

The Sig Sauer MCX barrel and gas block assembly in 5.56 NATO gives you a complete, ready-to-install upper component for your MCX platform rifle. Whether you're upgrading to a different barrel length, replacing a worn component, or building out a modular MCX setup for different roles, this 11.5-inch assembly combines the barrel and gas block as a matched unit—eliminating the guesswork of pairing components separately and saving you time at the workbench.

The 11.5-inch length strikes a balance between velocity and maneuverability, making it a practical choice for close-to-mid-range work, home defense, or compact tactical carbines where a longer barrel isn't needed. Since it's a factory Sig assembly, you get the fit and function Sig engineered into the MCX platform without aftermarket compatibility headaches.

Drop-in installation on any compatible MCX lower means minimal gunsmithing. This is the kind of modular flexibility that makes the MCX so capable—swap barrels and gas blocks as your mission or hunting scenario changes, all with the confidence that comes from using OEM Sig Sauer parts.

Key Features

• Complete barrel and gas block assembly—matched components ready to install
• 11.5-inch barrel length optimized for compact, maneuverable configurations
• 5.56 NATO chambering for broad ammo availability and compatibility
• Factory Sig Sauer engineering and fit for MCX platform reliability
• Modular design allows quick barrel swaps on compatible MCX lowers

Specifications

Frequently Asked Questions

Will this MCX barrel assembly fit my Sig MCX lower?

Yes, this assembly is designed for the MCX platform and will install on any compatible MCX lower receiver. It's a factory Sig component built to OEM specifications for proper fit and function.

What's included in this barrel and gas block assembly?

You receive the complete assembly—barrel and gas block matched and ready to install as a unit. No additional components are required for installation on a compatible MCX lower.

Is the 11.5-inch barrel suitable for hunting?

The 11.5-inch length is effective for hunting applications where you need a compact, maneuverable rifle, such as close-to-mid-range hunting in brush or timber. Performance and velocity depend on your specific ammunition and use case.

Can I use this with standard 5.56 NATO ammunition?

Yes, this assembly is chambered in 5.56 NATO, which is widely available and compatible with this barrel.