The Diamondback DB15 in .300 BLACKOUT is a semi-automatic pistol-format AR with a 10-inch barrel, aluminum stock, and Magpul grip. At 5.40 lbs and 26" overall, it's compact enough for close-quarters use. The optic-ready top rail accepts standard AR-footprint optics. Manual thumb safety follows standard AR placement. 
 

Key Specifications 

• SKU: 2024020478 
• UPC: 810035755611 
• Condition: New in Box 
• Finish: Black Stock Finish 
• Safety: Manual Thumb Safety 
• Trigger: Standard Trigger 
• Grip: Magpul Grip 
• Stock: Aluminum Stock 
• Weight: 5.40 lbs 
• Sights: Optic Ready 
• Length: 26" 
• Barrel Length: 10" 
• Capacity: 28+1 RD 
• Action: Semi-Auto 
• Caliber: 300 BLACKOUT 
• MPN: DB1915B061 
• Model Name: DB15 
• Brand: Diamondback 
   

Detailed Features 

 
.300 BLACKOUT was specifically engineered around short barrels — a 10-inch tube retains good supersonic performance and also works well with subsonic loads for suppressed use. The 10-inch barrel loses less velocity with this cartridge than 5.56 would. The 28+1 capacity uses standard AR magazines, which is a practical advantage. Optic-ready means no iron sights are included; plan for a red dot or similar. 
 
The aluminum stock and Magpul grip are durable and keep weight in check. The black finish is simple and practical. 
 

Usage 

 
The DB15 in .300 BLK works well for home defense and compact range use, and the caliber's subsonic/supersonic flexibility makes it a natural fit if you're running a suppressor. At 5.40 lbs it won't fatigue you during range sessions. For hunting small game with subsonic loads, it functions well — though range is limited compared to supersonic rifle cartridges.

The Diamondback DB15 in .300 BLK gets solid marks for its compact design and caliber choice, with reliability notes that matter for buyers.

The compact build is the most cited positive — buyers who wanted a short, light .300 BLK platform find it delivers. The lightweight construction makes it easy to handle and carry, and the .300 BLK versatility with both subsonic and supersonic loads is genuinely appreciated by users who run suppressors or want ammo flexibility. Price is frequently mentioned as a strength — most buyers feel it undercuts comparable alternatives.

Feeding reliability with certain ammunition or magazines is the primary concern. Some users have experienced issues under specific conditions, which matters for a gun intended for defensive use. The recommendation to test thoroughly with your specific ammo and magazines before trusting it comes up repeatedly in user discussions. The short barrel also produces more perceived recoil than longer-barreled versions of the same cartridge.

Overall, it's a practical, affordable .300 BLK pistol that earns buyer confidence when properly tested beforehand.