Sig Sauer MCX Piston (J02) Assembly – 11.5″ Barrel | 5.56 NATO
Not Yet Rated | Write the First Review SKU: 222-SIG-KIT-MCX-PISTON-11B-556
UPC: 799000000000
MFG#: KIT-MCX-PISTON-11B-556

Sig Sauer MCX Piston (J02) Assembly – 11.5″ Barrel | 5.56 NATO

Mid-Length Gas System Precision. Built for Compact MCX Power.

Maintain flawless cycling and performance with the Sig Sauer MCX Piston (J02) Assembly designed specifically for 11.5″ barrels in 5.56 NATO/.223 Rem. Engineered to regulate gas flow in suppressed and unsuppressed operations, this complete piston kit provides factory-level reliability and control over your MCX’s short-stroke gas system.

Whether you're replacing worn parts or upgrading a high-use upper, this OEM Sig Sauer piston assembly ensures clean operation, consistent ejection, and optimal dwell time in mid-length 5.56 builds—making it a mission-ready component for compact MCX rifle configurations.

🔧 Key Features:

• ✅ Genuine Sig Sauer OEM Part – Factory-issue piston assembly built for 11.5″ MCX 5.56 rifles.

• 🔩 Complete Gas System Kit – Includes piston, spiral gas ring, adjustable gas valve, and lever.

• 🎯 Tuned for 5.56 NATO / .223 Rem – Ensures precise gas flow and ejection in 11.5" barrel configurations.

• 🔁 Suppressor-Ready Performance – Adjustable gas valve enhances reliability when suppressed.

• 🧱 Steel Construction – Built tough to withstand high pressures and high heat in dynamic firing conditions.

Included in This Kit:

• Piston (5.56 NATO Specific)

• Spiral Gas Ring

• Gas Valve

• Gas Valve Lever

Engineered for use as a full unit. Do not substitute individual components.

Technical Specifications:

⚠️ Installation Notice:

This component requires disassembly beyond routine field stripping. SIG Sauer recommends installation by a certified armorer or qualified gunsmith. Improper installation or the use of mismatched parts may result in malfunction, damage, or serious injury.