Diamondback 300 Blackout 10" Pistol-Length Barrel - Black Nitride 4150 Chrome Moly Vanadium Steel (OEM Replacement)

The Diamondback 300 Blackout 10" pistol-length barrel gives you a proven swap-in replacement for pistol-caliber AR builds running subsonic or supersonic ammunition. Built from 4150 chrome moly vanadium steel with a black nitride finish, this barrel handles the abuse of suppressed shooting, short-range drills, and duty-grade use while resisting corrosion and wear. The 1:8 twist rate stabilizes .300 Blackout projectiles across the velocity spectrum—whether you're running heavy subsonic rounds or standard-pressure loads—making it a versatile core for any 300 BLK pistol or short-barrel rifle (SBR) platform.

This is an OEM-quality replacement barrel engineered for shooters who demand reliability in a compact package. The 10" length keeps overall profile short and handy, the heavy contour resists barrel whip and thermal stress, and the M4 feed ramps ensure smooth chambering cycle after cycle. Whether you're building a new pistol, rebarreling an existing upper, or setting up a dedicated subsonic host, the predictable ballistics and tight tolerances of a quality barrel matter more than you'd think—especially in suppressed applications where bullet stabilization and velocity consistency directly affect sound signature and accuracy.

Diamondback's button-rifled bore and 11° target crown deliver the precision you'd expect from a production barrel at this level. The 5/8 x 24 thread pattern is the standard for 300 Blackout and pairs with virtually any .30-caliber suppressor or muzzle device. Nitride finish stands up to carbon buildup from suppressed fire better than bare steel, reducing maintenance headaches and extending barrel life in hard-use situations.

Key Features

• 1:8 twist optimized for .300 Blackout across subsonic and standard-velocity loads
• Heavy contour reduces harmonics and barrel flex under rapid fire
• Black nitride finish resists corrosion and carbon fouling
• M4 feed ramps for reliable feeding from standard AR magazines
• 11° target crown supports accuracy and suppressor mounting
• Button-rifled 6-groove bore for consistent performance
• Pistol-length gas system compatible with most 300 BLK builds

Specifications

Frequently Asked Questions

Will this barrel work with my 300 Blackout upper?

Yes, provided your upper accepts a standard pistol-length 300 Blackout barrel with a 5/8 x 24 thread pattern. This is an OEM-replacement barrel, so it's designed to drop into any AR-15 upper that was originally chambered in .300 Blackout. Check that your gas tube length matches pistol-length specs.

What's the difference between the 1:8 twist and other rates for 300 Blackout?

The 1:8 twist is the standard for .300 Blackout and works reliably with both subsonic rounds (typical weight 208–240 gr) and standard-pressure loads (100–125 gr). It provides stable flight across that wide velocity range without over-stabilizing lighter bullets.

Is this barrel suppressor-ready?

Yes. The 5/8 x 24 thread pattern is standard for .30-caliber suppressors. The 11° target crown is designed to support suppressor mounting and helps maintain a clean bore interface.

What's included?

This is a barrel only. You'll need your own upper receiver, bolt carrier group, gas tube, and handguard to complete an assembly.