The Diamondback Carbon DB15 Pistol is a semi-automatic AR-pistol chambered in .300 AAC Blackout with a 10" barrel, FDE Cerakote finish, and 5/8x24 threaded muzzle. It runs both supersonic and subsonic .300 BLK loads and is sized for .30-cal suppressors out of the box. 
 

Key Specifications 

• Manufacturer: Diamondback Firearms 
• Family: Carbon Series 
• Model: Carbon DB15 Pistol 
• Type: Semi-Auto Pistol 
• Action: Semi-Auto 
• Caliber/Gauge: 300 AAC Blackout 
• Finish: FDE Cerakote  
• Barrel Length: 10" 
• Rate of Twist: 1-in-8 
• Capacity: 30 + 1  
• Number of Magazines: 1  
• Magazine Description: 30rd. PMAG  
• Sights Type: None  
• Thread Pattern: 5/8x24  
• Special Feature: Threaded Barrel  
• Weight: 5.7 lbs.  
• Safety Features: 2-position thumb safety  
• Receiver Material: Forged 7075 T6 Aluminum  
• Additional Info: 
  • 9" PC M-Lok Rail  
  • SBA3 Brace  
  • Magpul MOE Grip  
     

Detailed Features 

The 10" barrel with a 1-in-8 twist handles the typical .300 BLK bullet-weight range. At 5.7 lbs., it's on the lighter end for a .300 BLK AR-pistol. The forged 7075 T6 receiver holds up to normal use, and the 9" M-Lok rail gives you room for a light, foregrip, or other accessories. 
 
The 5/8x24 threaded muzzle is the right size for .30-cal suppressors — a key practical advantage for anyone running subsonic .300 BLK quietly. FDE Cerakote is an applied finish rather than just a coating, so it handles moisture and abrasion reasonably well. 
 
A Magpul MOE Grip and adjustable SBA3 Brace come standard. One 30-round PMAG is included. 
 

Usage Scenarios 

• Home Defense: Compact, 30+1 rounds, and subsonic .300 BLK loads offer reduced over-penetration vs. 5.56 
• Competitive Shooting: Light weight and fast follow-up capability 

The Diamondback Carbon DB15 in .300 AAC Blackout with FDE Cerakote gets positive attention for its light weight and the practical flexibility of the .300 BLK chambering. Owners who want to run both supersonic and subsonic loads — particularly suppressed — find the 5/8x24 threaded barrel and .300 BLK caliber combination appealing. The FDE finish gets consistently good marks for looks and real-world durability.

Reliability feedback is mixed. Most owners report acceptable cycling with standard loads, but feeding issues with certain ammo types or brands come up with some regularity. .300 BLK ammo selection matters more on some AR-platform pistols than others, and this one isn't immune to that.

Price comparisons to other AR-pistol options appear frequently. Some owners feel the value proposition is solid; others believe there are better-built alternatives at similar price points. The overall impression is positive but conditional — it works well for many owners, but ammo compatibility testing before relying on it is a reasonable precaution.