Proof Research 12.5" Carbon Fiber Wrapped AR Barrel - 300 Blackout, 1:8 Twist, Pistol Length Gas, 5/8-24 TPI

If you're building a short-barreled 300 Blackout AR—whether for a suppressed precision rig, a compact home-defense platform, or a lightweight hunting carbine—the Proof Research 12.5" Carbon Fiber Wrapped AR Barrel delivers match-grade accuracy in a package that won't bog down your gun. This is a purpose-built barrel for shooters who refuse to compromise on precision while keeping their setup nimble and fast-handling. The 1:8 twist rate stabilizes a wide range of 300 Blackout projectiles, from heavy subsonic loads to lighter supersonic rounds, making it genuinely versatile for both suppressed and unsuppressed shooting.

Proof Research's carbon fiber construction isn't hype—it's engineering. The barrel is considerably lighter than steel, which matters on a short platform where every ounce counts toward ergonomics and handling. That weight savings never comes at the expense of durability or accuracy; the carbon wrapping manages heat better than steel, keeping barrel temperatures down during extended strings of fire and reducing the kind of thermal expansion that shifts zero. You'll also get less harmonic vibration, which translates directly to tighter groups and more predictable performance shot to shot.

The 5/8-24 TPI threading is the 300 Blackout standard for suppressors and muzzle devices, so integration with your existing hardware is straightforward. Pistol-length gas is the right choice for a 12.5" barrel, keeping the system balanced and reliable across a broad range of ammunition. This barrel is built for shooters who understand that short-range precision and rugged dependability aren't mutually exclusive—they just require the right gear.

Key Features

• Carbon fiber wrapped construction for superior heat management and reduced weight compared to steel barrels
• Match-grade accuracy suitable for precision shooting and hunting applications
• 1:8 twist rate optimized for 300 Blackout across subsonic and supersonic loads
• Pistol-length gas system tuned for 12.5" barrel length
• 5/8-24 TPI threading compatible with standard 300 Blackout suppressors and muzzle devices
• Reduced harmonic vibration for consistent shot-to-shot performance
• No point-of-impact shift during high-volume shooting

Specifications

Frequently Asked Questions

Will this barrel work with 300 Blackout suppressors?

Yes. The 5/8-24 TPI threading is the standard for 300 Blackout suppressors, so any suppressor with that connection will thread on directly.

What's the difference between pistol-length and mid-length gas on a short AR barrel?

Pistol-length gas is optimized for shorter overall systems like this 12.5" build. It provides reliable operation and proper cycling tuned to the barrel length and system weight.

Can I use both subsonic and supersonic 300 Blackout ammunition in this barrel?

Yes. The 1:8 twist rate is designed to stabilize the full range of 300 Blackout loads, including both heavy subsonic rounds and lighter supersonic ammunition.

How much lighter is a carbon fiber barrel than steel?

Carbon fiber barrels are up to 64% lighter than traditional steel barrels of comparable length and profile, which meaningfully reduces overall system weight on a short-barreled platform.