SIG SAUER MCX SPEAR-LT 5.56 NATO 16-Inch Rifle

Description

The SIG SAUER MCX SPEAR-LT 5.56 NATO rifle combines the modular MCX operating system with a lighter, refined receiver and a full-length 16-inch barrel. This black configuration is manufacturer part number WRMCX-556N-16B-LT with UPC 798681648115. It uses a short-stroke gas-piston action, adjustable gas system, folding telescoping stock, and free-floating M-LOK handguard to deliver a flexible modern sporting rifle platform.

MCX Gas-Piston Operating System

Unlike a conventional direct-impingement AR-pattern rifle, the MCX SPEAR-LT uses a short-stroke piston to cycle the action. The piston system keeps the recoil assembly above the receiver rather than extending into a fixed buffer tube. This architecture is what allows the rifle to operate with its stock folded and gives the platform its distinctive compact storage profile. An adjustable gas regulator lets the operator select the appropriate setting for normal conditions or changed operating requirements.

The 16-inch barrel provides a familiar rifle-length configuration for 5.56 NATO ammunition. Its chrome-lined, cold-hammer-forged construction is designed for durability and service life. A SIG QD suppressor-ready flash hider is installed at the muzzle. The barrel assembly can be removed as part of the MCX modular system, though installation, inspection, and maintenance should always follow SIG SAUER’s current armorer or owner documentation.

Lightweight, Rigid Upper Assembly

The SPEAR-LT generation reduces weight while preserving the rigidity needed for a free-floating handguard. Its monolithic-style upper receiver and slim aluminum handguard create an uninterrupted top rail for compatible sights and optics. M-LOK slots along the handguard provide attachment points for lights, sling hardware, and other properly fitted accessories without requiring a full-length quad rail.

A redesigned handguard retention system helps maintain a secure interface between the receiver and rail. The charging handle is ambidextrous, and the rifle also includes an accessible side-mounted charging handle. This dual arrangement gives users more than one way to operate the action while maintaining control of the rifle.

Ambidextrous Controls and Folding Stock

SIG designed the MCX SPEAR-LT around ambidextrous operation. The safety selector, magazine release, bolt controls, and charging interface are arranged to support right- or left-handed handling. The lower receiver accepts standard-pattern pistol grips, and the integral 1913 rear interface supports the included folding, telescoping stock.

Folding the stock reduces overall storage length without disabling the action because the recoil mechanism is contained within the upper receiver. The stock can also be adjusted for length of pull. These features make the rifle easier to fit to different shooters or equipment configurations while keeping the controls and operating sequence consistent.

Factory Configuration

This rifle is finished in black and supplied with a 30-round magazine. The continuous top rail is ready for a compatible optic or iron-sight set. Because laws governing magazine capacity and rifle configurations vary, buyers should confirm local requirements before ordering or transferring this firearm.

Key Specifications

• Manufacturer: SIG SAUER
• Model: MCX SPEAR-LT
• Manufacturer part number: WRMCX-556N-16B-LT
• UPC: 798681648115
• Caliber: 5.56 NATO
• Action: Semi-automatic, short-stroke gas piston
• Barrel length: 16 inches
• Gas system: Adjustable
• Handguard: Free-floating aluminum M-LOK
• Upper rail: Continuous 1913 Picatinny
• Stock: Folding and telescoping
• Controls: Ambidextrous
• Finish: Black
• Magazine: 30-round

Practical Fit

The MCX SPEAR-LT is built for owners who want a piston-driven 5.56 rifle with broad accessory compatibility and a stock that folds without affecting operation. Its 16-inch barrel, adjustable gas system, modular handguard, and ambidextrous controls make it suitable for structured range training and general sporting use. Before use, read the current SIG SAUER manual, verify that all accessories are correctly installed, and follow established safe-handling, transport, and storage practices.