The Rock River Arms LAR-15M CAR A4 is a semi-automatic rifle chambered in .300 AAC Blackout with a 16-inch chrome moly steel barrel, 1:8 twist, and direct impingement action. It holds 30+1 rounds and weighs 7.3 lbs with a black hardcoat anodized aluminum receiver. 
 

Key Specifications 

• Model: LAR-15M CAR A4 
• Brand: Rock River Arms 
• Caliber: .300 AAC Blackout 
• Action Type: Semi-Automatic (Direct Impingement) 
• Barrel Length: 16 inches 
• Capacity: 30 + 1 rounds 
• Weight: 7.3 lbs. 
• Finish: Black Hardcoat Anodized 
• Receiver Material: Aluminum 
   

Features 

The RRA 6-position tactical CAR stock adjusts length of pull for different shooters. The two-stage match trigger has a crisp break that holds up over long range sessions. A railed gas block accepts optics and accessories. The .300 Blackout chambering handles both supersonic and subsonic loads, which gives it real flexibility depending on whether you're running a suppressor or not.

The LAR-15M CAR A4 in .300 AAC Blackout gets a generally positive reception, with a few recurring gripes.

Build quality is where most owners start — the rifle feels solid and the materials hold up to regular use. Accuracy is a consistent strength; the 1:8 twist handles the .300 Blackout well at typical engagement distances, and subsonic performance gets called out specifically. The AR platform's modularity means adding optics, grips, or other accessories is straightforward, and users take advantage of that.

On the negative side, weight comes up often. At 7.3 lbs it sits heavier than some comparable AR builds, which matters during extended carry. Price is another point of friction — the rifle costs a bit more than some competitors with similar specs, though most owners feel the quality warrants it. A few buyers have noted needing to make adjustments right out of the box before it met their preferences.