The Rock River Arms LAR-15M is an AR-style pistol chambered in .300 AAC Blackout, built around an 8-inch chrome moly barrel and a matching M-LOK handguard. It ships with an SB Tactical SBA3 arm brace instead of a fixed stock, keeping the overall package short for close-range use. The upper and lower use a black anodized aluminum receiver set with a Picatinny rail on top for mounting an optic. 
 

Key Specifications 

• Brand: Rock River Arms 
• Model: LAR-15M 
• Caliber: .300 AAC Blackout 
• Action: Semi Auto 
• Capacity: 30+1 
• Barrel Length: 8" 
• Weight: 5.20 lbs 
• Finish: Black 
   

Detailed Features 

• M-LOK handguard runs the length of the 8-inch barrel for lights, grips, or a sling mount. 
• SB Tactical SBA3 arm brace attaches in place of a fixed stock, and the rifle ships without sights so the buyer supplies an optic. 
• Chrome moly steel barrel carries a 1:9 twist and a flash hider at the muzzle. 
• Black Hogue rubber grip and a single-stage trigger make up the controls. 
• Aluminum receiver has a black anodized finish and a lever-style safety selector.

Owners of Rock River Arms AR-pattern guns generally report solid, reliable function out of the box, and the chrome moly barrels hold up well over time with few reported issues. The LAR-15M pistol configuration runs a bit heavier than some competing 300 Blackout pistols, which some buyers notice when carrying it for extended periods.

As a braced pistol, the LAR-15M is popular as a short, easy-to-maneuver range or truck gun. The SBA3 brace draws mixed reactions: some like the adjustable length it offers, others swap it for a different brace or stock. Running .300 Blackout through an 8-inch barrel produces more muzzle blast and flash than a longer carbine barrel, which is the most common complaint among owners.

Rock River Arms parts are widely compatible with the broader AR-15 aftermarket, so optics mounts and M-LOK accessories bolt on without hassle. Buyers moving up from budget AR builds tend to see the LAR-15M as a step up in fit and finish, and the Hogue grip is regarded as a comfortable stock component that many leave alone.