SIG SAUER MCX SPEAR-LT RMCX-556N-16B-LT — Description

The SIG SAUER MCX SPEAR-LT RMCX-556N-16B-LT is a premium 5.56 NATO / .223 Remington semi-automatic rifle designed as the next generation of SIG Sauer’s modular MCX rifle family. Built around a reliable short-stroke gas piston operating system, the SPEAR-LT combines enhanced durability, ambidextrous controls, modular design, and a lightweight folding stock configuration for a versatile modern rifle platform.

The SPEAR-LT features a 16-inch cold hammer forged barrel, Coyote finish, folding stock with cheek rest, and a lightweight free-floating M-LOK handguard. The rifle incorporates improvements over earlier MCX models, including an ambidextrous bolt catch and release, compatibility with AR-style triggers, and an updated modular receiver design.

Designed for performance and adaptability, the MCX SPEAR-LT offers optics-ready capability, a SIG flat-blade match trigger, suppressor-ready muzzle device, and compatibility with standard 5.56 NATO magazines. The combination of piston operation, folding stock design, and modular components makes it suitable for a wide range of sporting, training, and professional applications.

SIG SAUER MCX SPEAR-LT RMCX-556N-16B-LT — Specifications

Manufacturer: SIG SAUER
Model: MCX SPEAR-LT
Model Number: RMCX-556N-16B-LT
Caliber: .223 Remington / 5.56 NATO
Action: Semi-automatic
Operating System: Short-stroke gas piston
Platform: SIG MCX modular rifle system
Barrel Length: 16 inches
Barrel Material: Cold hammer forged carbon steel
Barrel Finish: Nitride finish
Barrel Twist Rate: 1:7″
Receiver Material: Aluminum
Finish: Coyote anodized finish
Stock: Folding stock with adjustable cheek rest
Handguard: Lightweight free-floating M-LOK handguard
Trigger: SIG flat-blade match trigger
Magazine Type: AR-15 / STANAG compatible detachable magazine
Magazine Capacity: 30 rounds
Controls: Fully ambidextrous controls
Muzzle Device: SIG QD suppressor-ready flash hider
Sights: Optics-ready upper receiver with full-length Picatinny rail
Overall Length: Approx. 35.75 inches (stock extended)
Weight: Approx. 7.4 lbs (configuration dependent)

Key Features

• .223 Remington / 5.56 NATO chambering
• Short-stroke gas piston system for reliable operation and reduced fouling
• 16-inch cold hammer forged barrel for durability and accuracy
• Coyote finish with premium MCX styling
• Folding stock with cheek rest for compact transport and storage
• Fully ambidextrous controls
• SIG flat-blade match trigger
• Free-floating M-LOK handguard
• Modular MCX architecture
• AR-15 magazine compatibility
• 30-round magazine capacity
• Optics-ready design

Package typically includes:

• SIG SAUER MCX SPEAR-LT 5.56 NATO rifle
• Folding stock assembly
• 30-round magazine (configuration dependent)
• Owner’s manual
• Safety documentation