Diamondback DB15 Combo 5.56 NATO & .300 Blackout, 16″ Barrel

About this product

The Diamondback DB15 combo pairs a traditional AR-style platform with two compatible uppers chambered for 5.56x45mm NATO and .300 AAC Blackout. It uses a gas-impingement operating system, CNC-machined components, and a carbine-length gas system for familiar AR handling. The package includes a 16″ 4140 chrome-moly barrel, an A3 flattop upper, a 12″ M-LOK handguard and Magpul MOE carbine stock and grip. This model is produced in the USA and ships with two ready-to-install uppers.

Key Specifications

• Chambering includes both 5.56x45mm NATO and .300 AAC Blackout.
• The barrel measures 16 inches and is described as 4140 chrome-moly steel.
• The firearm ships with a reported capacity of 30 + 1 rounds.
• The action is a semi-auto configuration.
• The muzzle device is an A2 Flash Hider.
• The overall length is listed as 32.50″-35.75″ depending on stock position.
• The finished weight is approximately 6.65 lbs.
• The stock is a Magpul Carbine design in black.
• The rifle is configured for right hand shooters.
• The barrel twist rate is 1:8″.

This DB15 combo offers an adaptable AR platform suitable for range use, general-purpose field applications, and home defense scenarios where multi-caliber flexibility is desired. With standard AR ergonomics, M-LOK modularity and two compatible uppers included, the package provides practical versatility without unnecessary complexity. Its blend of proven components and a familiar control layout make it a straightforward choice for users who want a multi-caliber AR setup built on a conventional carbine-length system.

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