Springfield Saint 5.56mm Semi-Automatic AR-15 Rifle with M-Lok Rail

Overview

The Springfield Saint 5.56mm Semi-Automatic AR-15 Rifle with M-Lok Rail is a direct-impingement platform engineered for reliability and precision under field conditions. Chambered in 5.56mm NATO, this rifle operates with a semi-automatic action and features a 16-inch chrome-moly vanadium barrel with a 1:8 twist rate, optimized for stabilizing both 55-grain and 62-grain projectiles. The M-Lok free-float handguard provides continuous attachment points for accessories while reducing overall weight compared to quad-rail systems. This model is assembled in Geneseo, Illinois, using 7075 T6 aluminum upper and lower receivers, with a Type III hard coat anodized finish for corrosion resistance. The Springfield Saint 5.56mm Semi-Automatic AR-15 Rifle with M-Lok Rail includes a B5 Systems stock and pistol grip, a nickel boron coated bolt carrier group, and a two-stage match-grade trigger with a 4.5 to 5.0 pound pull weight.

Features & Specs

The barrel is melonite treated for extended service life and accuracy retention, with a 4150 steel gas block and a pinned low-profile design. The muzzle is threaded 1/2×28 TPI and comes with a Springfield Armory double-port compensator to mitigate muzzle rise during rapid strings of fire. The handguard is a 15-inch M-Lok rail with full-length Picatinny top rail, providing 45-degree offset accessory mounting slots. The rifle ships with one Magpul PMAG 30-round magazine and a soft case.

• Caliber: 5.56mm NATO; operates with .223 Remington without modification
• Barrel length: 16 inches; overall length: 32.5 to 35.75 inches with six-position collapsible stock
• Weight: 6 pounds 14 ounces unloaded; includes ambidextrous safety selector and bolt catch
• Receiver material: 7075 T6 aluminum; upper receiver includes forward assist and ejection port dust cover

• Bolt carrier group: Nickel boron coated for reduced friction and ease of cleaning; MPI and HPT tested
• Trigger: Two-stage match-grade; first stage 2.5 pounds, second stage 2.0 to 2.5 pounds
• Handguard: 15-inch free-float M-Lok with heat shield; includes QD sling mount points
• Gas system: Carbine-length direct impingement with melonite gas tube

• Stock: B5 Systems SOPMOD with rubber buttpad and storage compartments
• Pistol grip: B5 Systems Type 23 with rubber overmolding
• Sights: None included; receiver is flat-top with Picatinny rail for optic mounting
• Finish: Type III hard coat anodized black; MIL-SPEC 8625 Class 2

Who It’s For

The Springfield Saint 5.56mm Semi-Automatic AR-15 Rifle with M-Lok Rail is suited for shooters who require a duty-grade carbine capable of sustained accuracy across varied conditions. It is appropriate for law enforcement patrol rifles, civilian self-defense applications, and three-gun competition where weight savings and modularity are priorities. The 1:8 twist barrel handles heavier match loads for precision shooting at intermediate ranges while remaining compatible with standard pressure ammunition. The two-stage trigger and nickel boron BCG appeal to users who prioritize a clean breaking trigger and reduced maintenance intervals. This model is not recommended for shooters seeking a fully custom build or those requiring a piston-driven operating system, as the direct impingement design transfers carbon to the chamber and bolt carrier group.

Shipping & FFL

This firearm ships to a Federal Firearms License (FFL) holder for transfer. Upon purchase, provide the shipping address of your chosen FFL dealer. We ship via insured carrier with adult signature required. Verify that your FFL dealer accepts transfers from out-of-state retailers. Some states and localities impose restrictions on semi-automatic rifles with detachable magazines; it is your responsibility to confirm compliance with all applicable laws before ordering. FFL dealers must provide a signed copy of their license and may charge a separate transfer fee. We do not ship to PO boxes or to addresses outside the United States. All firearm sales are final. The Springfield Saint 5.56mm Semi-Automatic AR-15 Rifle with M-Lok Rail is shipped in its original manufacturer packaging with one magazine and owner’s manual.