SIG Sauer MCX Full-Auto 9mm Upper Receiver w/ Handguard

For sale is a used SIG Sauer upper receiver assembly sourced from a full-auto SIG. This version includes the free-float handguard (as shown). Sold as the upper only—no lower receiver or other components beyond what is visible.

Features & Condition:

• Black anodized aluminum upper receiver with continuous top Picatinny (M1913) rail
• Free-float handguard with slotted attachment points (M-LOK/KeyMod-style cutouts)
• Flip-up front and rear iron sights mounted
• Compact red dot optic (SIG-style) mounted on the rail
• Ejection port with dust cover
• Barrel installed with multi-port muzzle device (flash hider/compensator style)
• Receiver, handguard, and barrel show typical handling scratches and use-related wear
• Short-stroke piston / MCX-style platform features

Notes for Buyers:

• Sold as upper receiver group only (handguard and optics included as pictured). Buyer is responsible for compatibility, function, headspace, and all legal compliance.
• Barrel length appears shorter than a standard rifle configuration—verify exact measurement. Short-barreled configurations may require NFA registration (Form 1/SBR, etc.) depending on final setup and jurisdiction. All NFA rules apply where relevant.
• Compatible with appropriate SIG MCX or adapter-equipped AR-pattern lowers (confirm fit). Full-auto capability depends on the lower receiver.
• Condition is used/as-is. No returns or guarantees of function. Inspect thoroughly or have a qualified gunsmith evaluate.

Photos show multiple angles of the complete upper with handguard, sights, and optic.