The Diamondback DB300P 10.5" 300 AAC Blackout AR-15 barrel is a drop-in replacement barrel built for shooters who want the versatility of subsonic capability without redesigning their platform. Whether you're running a dedicated .300 Blackout upper or swapping barrels on an existing AR, this 10.5-inch Diamondback barrel gives you the short, punchy performance that makes .300 Blackout such a practical choice for hunting, home defense, and suppressed shooting. The black Melonite finish resists corrosion and handles heavy use, so you're not babying this component—it's made to work.

At 10.5 inches, this barrel strikes a balance: short enough for handling and maneuverability in tight quarters, long enough to extract useful velocity from .300 Blackout's subsonic and supersonic loads. The barrel threads and dimensions are spec'd for standard AR-15 upper receivers, making installation straightforward for anyone comfortable swapping uppers or barrels. Diamondback Firearms built this for shooters who value reliability and no-nonsense performance over flashy features.

This is a component barrel, not a complete upper or firearm. You'll need a compatible AR-15 upper receiver, bolt carrier group, and charging handle to assemble a functioning upper. If you're expanding a .300 Blackout rig, upgrading from a longer barrel, or building a short-barreled AR from scratch, this Diamondback barrel is a solid, affordable foundation. Pair it with quality ammo—both subsonic and full-power loads perform well in this platform—and you've got a genuinely useful rifle configuration.

The Diamondback DB300P 10.5" 300 AAC Blackout AR-15 barrel is a drop-in replacement barrel built for shooters who want the versatility of subsonic capability without redesigning their platform. Whether you're running a dedicated .300 Blackout upper or swapping barrels on an existing AR, this 10.5-inch Diamondback barrel gives you the short, punchy performance that makes .300 Blackout such a practical choice for hunting, home defense, and suppressed shooting. The black Melonite finish resists corrosion and handles heavy use, so you're not babying this component—it's made to work.

At 10.5 inches, this barrel strikes a balance: short enough for handling and maneuverability in tight quarters, long enough to extract useful velocity from .300 Blackout's subsonic and supersonic loads. The barrel threads and dimensions are spec'd for standard AR-15 upper receivers, making installation straightforward for anyone comfortable swapping uppers or barrels. Diamondback Firearms built this for shooters who value reliability and no-nonsense performance over flashy features.

This is a component barrel, not a complete upper or firearm. You'll need a compatible AR-15 upper receiver, bolt carrier group, and charging handle to assemble a functioning upper. If you're expanding a .300 Blackout rig, upgrading from a longer barrel, or building a short-barreled AR from scratch, this Diamondback barrel is a solid, affordable foundation. Pair it with quality ammo—both subsonic and full-power loads perform well in this platform—and you've got a genuinely useful rifle configuration.