Diamondback OEM Replacement 5.56x45mm NATO 5.50" Pistol-Length Black Nitride Chrome Moly Vanadium Steel Barrel

If you're running a Diamondback AR pistol or SBR and need a drop-in replacement barrel, the Diamondback OEM Replacement 5.56x45mm NATO 5.50" Pistol-Length Black Nitride Chrome Moly Vanadium Steel Barrel is a straightforward choice. This is a genuine OEM part built to spec for Diamondback platforms—not an aftermarket upgrade, but the real deal that keeps your rifle running true. At 5.50 inches, it's right in the sweet spot for pistol-length gas systems, offering the compact handling you want without sacrificing velocity in an intermediate cartridge.

The barrel stock is 4150 chrome moly vanadium steel, a field-proven material that balances durability and cost-effectiveness. The black nitride finish is there to resist corrosion and wear—not a cosmetic choice, but a protective one that pays dividends over time, whether you're running suppressed, shooting hard, or dealing with weather. If you've got a worn-out factory barrel or simply need a spare, this OEM replacement drops into your receiver without guesswork or fitting headaches.

This is the kind of part you buy when you know what you need and want to get back to shooting. No surprises, no special tools required—just solid, mil-spec iron that does its job.

Key Features

• 5.56x45mm NATO chambering—standard rifle cartridge with wide ammunition availability
• 5.50" pistol-length configuration for compact AR pistols and short-barreled rifles
• Black nitride finish for corrosion and wear resistance
• 4150 chrome moly vanadium steel construction for strength and longevity
• OEM Diamondback replacement—direct fit for compatible platforms

Specifications

Frequently Asked Questions

Will this barrel fit my Diamondback AR pistol?

This is an OEM Diamondback replacement barrel, so it's designed as a direct fit for compatible Diamondback platforms. If you're unsure whether your specific model is compatible, we recommend confirming with Diamondback or checking your rifle's documentation before ordering.

What's the difference between pistol-length and carbine-length gas systems?

Pistol-length gas systems are shorter, placing the gas port and tube closer to the muzzle. This setup is common on short-barreled AR pistols and SBRs to maintain proper cycling reliability. Carbine-length barrels are longer and suit full-size rifles. They're not interchangeable—your upper receiver is designed for one or the other.

Can I use standard 5.56 NATO ammunition?

Yes. This barrel is chambered in 5.56x45mm NATO, the standard rifle cartridge. You can use factory 5.56 ammo and most .223 Remington ammunition (though always check your specific rifle's manual for any guidance).

What does black nitride finish do?

Black nitride is a surface hardening process that resists corrosion, wear, and fouling. It protects the barrel steel underneath and makes cleaning easier over time, especially if you shoot suppressed or in wet conditions.