DIAMONDBACK DB15 5.56 NATO SEMI-AUTO PISTOL W/300 BLACKOUT UPPER

The Diamondback DB15 Combo Kit delivers exceptional versatility in a compact Modern Sporting Rifle (MSR) pistol platform by combining two complete upper assemblies with a single AR‑15 pistol lower. The primary configuration features a 7” 5.56 NATO pistol, ideal for compact handling and close‑quarters performance, while the included 10” .300 AAC Blackout upper allows fast caliber conversion for optimized suppressed or subsonic use.

By simply swapping uppers, shooters can transition between calibers while maintaining consistent ergonomics and controls. This combo kit is built on forged 7075‑T6 aluminum receivers and equipped with M‑LOK handguards for accessory flexibility, making it an adaptable solution for range use and multi‑role applications.

FEATURES

• Dual‑caliber combo package with two complete uppers
• 7” 5.56 NATO pistol configuration (installed)
• Additional 10” .300 AAC Blackout complete upper
• Forged 7075‑T6 aluminum upper and lower receivers
• Free‑float M‑LOK handguards on both uppers
• Pistol‑length gas systems for both calibers
• A2 flash hiders (caliber‑appropriate thread patterns)
• Magpul MOE pistol grip
• Pistol buffer tube with foam cover
• BCG and charging handle shared between uppers (one set included)

SPECS

• Manufacturer: Diamondback Firearms
• Model: DB15
• Platform: AR‑15 / MSR Pistol
• Action: Semi‑Automatic
• Gas System: Pistol Length (both uppers)
• Capacity: 30+1 (where legal)
• Finish: Black, Hard Coat Anodized
• 5.56 NATO UPPER
• Barrel Length: 7”
• Barrel Material: Chrome‑Moly, Black Nitride Finish
• Twist Rate: 1:8 RH
• Muzzle Thread: 1/2x28
• Muzzle Device: A2 Flash Hider
• .300 AAC BLACKOUT UPPER
• Barrel Length: 10”
• Barrel Material: Chrome‑Moly, Black Nitride Finish
• Muzzle Thread: 5/8x24
• Muzzle Device: A2 Flash Hider
• Controls: Standard AR‑15
• Sights: Optic‑Ready Flat Top"