Diamondback DB15 Combo 5.56 & .300 BLK 16 in.

About this product

The Diamondback DB15 Combo provides two complete 16″ AR-style configurations in one package: a primary 5.56 NATO carbine and a compatible .300 AAC Blackout complete upper. Both setups use a carbine-length gas system, a 12″ M-LOK handguard and a forged A3 flat-top upper for familiar AR ergonomics and accessory mounting. The rifle is outfitted with Magpul MOE furniture and ships with two 30‑round magazines for standard capacity handling.

Key Specifications

• Chambering includes 5.56 NATO and a complete .300 AAC Blackout upper for caliber flexibility.
• The barrel length for the primary and included upper is 16 inches.
• The barrel finish is Black Nitride for increased surface hardness and corrosion resistance.
• The twist rate is 1:8 for the listed barrels.
• The gas system is a carbine-length configuration on both assemblies.
• The bolt carrier group is a shot-peened, MPI Mil-Spec 8620 carrier.
• The upper is a forged A3 flat-top 7075 T6 aluminum receiver.
• The handguard is a 12-inch M-LOK free-float rail for accessory attachment.
• Included furniture is a Magpul MOE carbine stock and MOE grip.
• Magazines included are 2 × 30‑round PMAGs and the muzzle device is an A2 flash hider (1/2-28).

This DB15 Combo is built for shooters who want straightforward, multi-caliber capability with common AR controls and accessories. Its two 16″ configurations let you tailor the setup for general range use and flexible mission profiles while keeping maintenance and ergonomics familiar. The combination of a forged A3 upper, M-LOK handguard and Magpul furniture delivers practical utility and modularity for shooters focused on reliable performance and adaptability.

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