Sig Sauer MCX-Spear LT Upper Receiver Features The Sig Sauer MCX-Spear LT Upper Receiver is built around a 9 threaded barrel with 5/8x24 thread pitch and an adjustable gas system optimized for suppressed use with SIG SLH and SLX suppressors delivering reliable cycling across both suppressed and unsuppressed 300 Blackout loads in a platform developed for the special forces community. The dual rod recoil assembly eliminates the standard buffer system entirely and the receiver extension delete stock adapter allows any folding or static stock or brace using a vertical 1913 rail system to mount directly without modification to the host lower. A tapered bolt design and quick change barrel system deliver enhanced lockup reliability and fast field reconfiguration across the MCX-SPEAR LT s modular platform architecture. The complete 300 Blackout upper ships with an ambidextrous charging handle with gas deflector and bolt carrier group for immediate drop-in installation on any M4/AR-15 spec lower assembly without additional components. The removable 3-prong flash hider provides effective muzzle blast mitigation and transitions directly to SIG SLH and SLX suppressor configurations via a quick-detach interface for seamless suppressed shooting capability. An M4 adapter enables Picatinny rail folding stock capability on any compatible M4 lower and the flat top receiver accommodates standard AR-height optics and accessories across all mounting configurations. Sig Sauer MCX-Spear LT Upper Receiver Specifications Manufacturer: Sig Sauer Model: MCX-Spear LT Upper Receiver Caliber: 300 Blackout Color: FDE Barrel Length: 9 Barrel Type: Threaded Thread Pitch: 5/8x24 Muzzle Device: 3-Prong/SIG Suppressor QD Flash Hider Gas System: Adjustable Recoil System: Dual Rod Receiver: Flat Top Finish: Anodized Compatible Lowers: M4/AR-15 Spec Compatible Suppressors: SLX/SLH Stock Adapter: Receiver Extension Delete/Vertical 1913 Rail Includes: Ambidextrous Charging Handle w/Gas Deflector Bolt Carrier Group Receiver Extension Delete Stock Adapter