SIG MCX-SPEAR LT .300 BLK Semi-Auto SBR | 5.5" Barrel

SIG Sauer MCX-SPEAR LT .300 BLK 5.5" SBR – Black | Compact Short-Stroke Piston Rifle (WRMCX-300B-5B-R-LT-SBR)

Product Description
The SIG Sauer MCX-SPEAR LT in .300 Blackout with a 5.5" barrel is a highly compact, mission-adaptable short-barreled rifle (SBR) built on SIG’s proven short-stroke gas piston platform. Designed for close-quarters, special operations, and suppressed applications, it delivers the modularity and reliability of the MCX family in an ultra-compact package.

Featuring an adjustable gas system for reliable suppressed or unsuppressed operation, a folding minimalist stock, lightweight M-LOK/Picatinny handguard, and fully ambidextrous controls, the SPEAR LT is optimized for PDW-style use. The 5.5" cold-hammer-forged barrel with 1:5 twist stabilizes both supersonic and subsonic .300 BLK ammunition. It ships with a SIG QD suppressor-ready flash hider and accepts standard AR-15 magazines.

Finished in black anodized, this SBR folds to just 17.1" for maximum stowability while remaining a highly capable fighting platform.

Key Specifications & Features

• Caliber: .300 Blackout (300 BLK)
• Barrel Length: 5.5"
• Twist Rate: 1:5
• Muzzle Threads: 5/8"-24 (tapered shoulder)
• Operating System: Short-stroke gas piston with adjustable gas
• Stock: Folding minimalist
• Handguard: Alloy M-LOK / Picatinny
• Trigger: SIG match-style
• Overall Length: 24" (stock extended)
• Folded Length: 17.1"
• Weight: 5.8 lbs
• Finish: Black anodized
• Magazine: Accepts AR-15 magazines (1 × 30-round polymer included)
• Suppressor-ready SIG QD flash hider
• Fully ambidextrous controls
• NFA item (Short-Barreled Rifle)

The SIG MCX-SPEAR LT 5.5" .300 BLK SBR is ideal for operators and professionals seeking a lightweight, highly compact, and suppressor-optimized platform for close-quarters and specialized roles.