The Diamondback DB15 is an AR-pattern semi-automatic rifle chambered in 5.56 NATO with a 16-inch cold hammer-forged threaded barrel produced in collaboration with Knight's Armament Company. It has a 30+1 capacity, a 15-inch M-Lok rail, and ships with MBUS backup sights. The matte black finish covers the full-length rail and receiver. 
 

Key Specifications 

• Brand: Diamondback Firearms 
• Model: DB15 
• Caliber: 5.56 NATO 
• Action: Semi Auto 
• Capacity: 30+1 
• Barrel Length: 16" 
• Color/Finish: Matte Black 
   

Detailed Features 

• 16-inch Knight's Armament cold hammer-forged threaded barrel 
• 15-inch M-Lok handguard rail 
• MBUS backup iron sights included 
• Magpul CTR stock

Owners of the DB15 Knight's Armament collaboration tend to focus on the barrel as the reason to buy this particular build. A KAC cold hammer-forged barrel on a mid-tier AR-pattern rifle is an unusual pairing, and most owners who specifically sought this model did so for that barrel quality at the price point.

The M-Lok rail length and included MBUS sights are consistently mentioned as practical additions that reduce out-of-box setup cost. The Magpul CTR stock gets standard positive mention. The overall fit and finish receives approval, though some owners note the lower-tier components elsewhere in the build don't quite match the quality of the barrel.

Long-term owners report the DB15 platform is reliable across a range of .223 and 5.56 loads. The threaded barrel adds suppressor or muzzle device flexibility. A few owners note the collaboration branding carries some premium over comparable non-KAC builds, and opinions split on whether that premium is justified by the full package.