Diamondback DB15 Combo 5.56/.300 BLK 16" Dual Upper Kit

The Diamondback DB1721K001 DB15 Combo delivers exceptional versatility with two complete upper receivers chambered in 5.56x45mm NATO and .300 Blackout. This dual-caliber system allows shooters to switch between high-velocity rifle rounds and subsonic capabilities without purchasing separate firearms.

What Makes This Different

Most AR-15 platforms require separate complete rifles for different calibers, but this combo package includes both uppers on a single serialized lower receiver. The carbon fiber receiver construction reduces weight by approximately 20% compared to traditional aluminum alternatives while maintaining structural integrity. Both 16-inch barrels feature 1:7 twist rates optimized for stabilizing heavier projectiles in their respective calibers.

Key Features

• Dual upper receivers: 5.56x45mm NATO and .300 Blackout with 16-inch barrels
• Carbon fiber lower receiver reduces overall system weight
• 12-inch M-LOK handguard provides modular attachment points
• Magpul MOE carbine stock and grip for enhanced ergonomics
• 30-round magazine capacity with standard STANAG compatibility
• Direct impingement gas system with carbine-length gas tube
• Mil-spec trigger group and buffer system

The 5.56 upper excels in long-range applications and barrier penetration, while the .300 Blackout configuration offers superior performance with suppressors and heavier bullets. Both calibers utilize the same bolt carrier group and magazines, simplifying logistics and reducing training requirements. The M-LOK handguard accepts standard accessories including lights, grips, and bipods without additional rail sections.

Technical Specs

• Calibers: 5.56x45mm NATO and .300 AAC Blackout
• Barrel Length: 16 inches (both uppers)
• Twist Rate: 1:7 (both barrels)
• Overall Length: 32.25-35.5 inches (depending on stock position)
• Weight: Approximately 6.8 pounds (with single upper installed)
• Handguard: 12-inch M-LOK free-floating design
• Stock: Magpul MOE carbine stock with 6-position adjustment
• Grip: Magpul MOE pistol grip
• Magazine Capacity: 30+1 rounds
• Finish: Black anodized aluminum with carbon fiber lower

This combo package eliminates the need for multiple firearms while providing the tactical flexibility of two proven calibers. The carbon construction and quality components justify the investment for serious shooters seeking maximum adaptability.