Ar-15 Pistol Length 6 Barrel .300 Blackout

Building a short-barreled AR-15 pistol in .300 Blackout? The Ballistic Advantage AR-15 Pistol Length 6 Barrel in .300 Blackout delivers the compact package and subsonic-ready caliber that make this configuration so appealing for tactical builds, short-range hunting, and suppressed shooting. At 6 inches, this pistol-length barrel pairs the ballistic advantage of .300 Blackout with genuine portability—ideal if you're running a registered SBR, a 80%-lower pistol build, or need a lightweight truck gun that doesn't sacrifice on-target performance.

Ballistic Advantage machines this barrel from 4150 Chrome Moly Vanadium steel, the proven material standard for AR-15 barrels, and applies a QPQ corrosion-resistant finish for durability in the field or at the range. The 1:7 twist rate is optimized for .300 Blackout across the full spectrum of ammunition—from heavy subsonic loads to standard velocity rounds. The .750" gas block journal accepts standard AR-pattern gas blocks, and the QPQ-coated M4 feed ramp extension ensures reliable feeding into your upper receiver.

Important: This barrel is designed for pistol-configuration builds, registered SBRs, and registered machine guns only. Possessing this barrel on a non-NFA lower receiver (a standard rifle lower) is prohibited by federal law. Confirm your lower's registration status and configuration before purchase. All NFA and ATF rules apply.

Key Features

• 4150 Chrome Moly Vanadium construction for durability and longevity
• QPQ corrosion-resistant finish for reliable performance in wet or harsh conditions
• 1:7 inch twist rate optimized for .300 Blackout subsonic and standard ammunition
• .750" gas block journal for standard AR-15 gas block compatibility
• QPQ-coated M4 feed ramp extension for smooth feeding
• 6-inch pistol length—ideal for compact builds and suppressed shooting

Specifications

Frequently Asked Questions

Is this barrel legal for my AR-15 lower receiver?

This barrel is legal only on a registered SBR lower, a registered machine gun lower, or a pistol-configuration lower (with no stock, only a brace or no brace at all). Possessing this barrel on a standard rifle lower receiver is prohibited by federal law. Verify your lower's legal configuration and registration status before purchase.

What twist rate does this barrel have?

This Ballistic Advantage barrel has a 1:7 inch twist rate, which is optimized to stabilize both standard velocity and heavy subsonic .300 Blackout ammunition reliably.

What gas block size does it use?

The barrel features a .750" gas block journal, which accepts standard AR-15 pattern gas blocks.

Is this barrel good for suppressed shooting?

Yes. The 6-inch pistol-length barrel and 1:7 twist are both well-suited to .300 Blackout subsonic loads, which are popular in suppressed setups. The corrosion-resistant QPQ finish also helps withstand the additional fouling that suppressed shooting can generate.