Built to work and priced to own, the Sig Sauer MCX Spear-LT IR 5.56 16″ brings dependable 5.56 performance to the AR-15 platform without the premium cost of boutique manufacturers or the compromises of budget builds.

Chambered in 5.56 and running a direct impingement system, the Sig Sauer MCX Spear-LT IR 5.56 16″ is a semi-automatic AR-15 rifle engineered for consistent performance across a wide range of applications.

Proven Gas System: Running a direct impingement system that has proven itself across millions of rounds in the field, this 5.56 platform brings that reliability record to every range session and defensive use case.

Well-Balanced Profile: The 16″ barrel and free-float handguard combination keep this rifle handy without sacrificing the sight radius and velocity that make the 5.56 cartridge effective.

AR-15 Ecosystem Access: Standard AR-15 compatibility means accessories, replacement parts, and upgrade components are universally available — this rifle will never be an orphan platform.

Low-Maintenance Reliability: A quality finish and properly spec’d components reduce maintenance requirements without cutting corners on durability — more time shooting, less time cleaning.

Caliber: 5.56
Barrel Length: 16″
Gas System: Direct Impingement
Handguard: Free-Float
Muzzle Threading: 1/2×28
Magazine Capacity: 30-Round
Finish: Featuring the Gen II IR FDE Cerakote
Origin: Made in the USA

Works with standard AR-15 lower receivers and accepts STANAG 5.56 magazines. Designed for mil-spec carbine buffer systems and compatible with the full ecosystem of AR-15 parts and accessories.

Built from 7075 aluminum with a Featuring the Gen II IR FDE Cerakote finish, this AR-15 rifle holds up to sustained use without sacrificing dimensional accuracy or function.

Well-suited for home defense, recreational target shooting, and competitive carbine matches. A natural choice for shooters building a versatile general-purpose AR-15.

SIG SAUER is trusted by the U.S. military and law enforcement agencies worldwide. Their AR-15 lineup delivers the same premium quality and engineering that earned SIG that trust. Made in the USA.