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Diamondback makes the barrels that go into their own DB15 rifles, and this is the same spec — a 16-inch heavy profile 300 Blackout barrel with a pistol-length gas system, machined in-house on CNC equipment and inspected at multiple stages before it ships. You're getting a purpose-built component, not an afterthought sourced from overseas.
The steel is 4150 Chrome Moly Vanadium, which is the step up from the more common 4140 alloy. CMV was originally developed for military-grade rifle barrels and handles heat and pressure better over a long service life. Paired with the black nitride finish — a surface hardening process that penetrates into the steel rather than just coating it — you end up with a barrel that resists corrosion, cleans up easier than bare steel or chrome-lined, and holds up through heavy round counts without losing consistency.
The 1:8 right-hand twist is the sweet spot for 300 Blackout. It stabilizes everything from light 110-125 grain supersonic loads up through heavier 220 grain subsonic projectiles, so you're not locked into one type of ammo. That flexibility matters a lot with this cartridge.
The pistol-length gas system is a deliberate choice on a 16-inch 300 Blackout barrel. 300 BLK runs at lower pressure than 5.56, and the shorter gas tube gives the action more dwell time and helps ensure reliable cycling across a wider range of loads — especially subsonics, which can be finicky in a carbine-length setup. The muzzle is threaded 5/8×24, the standard pitch for 30-caliber suppressors and muzzle devices. M4 feed ramps and a target crown round out a feature set that punches well above the price point.
300 Blackout operates at lower pressures than 5.56, and the pistol-length gas system provides more consistent cycling across the full range of 300 BLK loads — particularly subsonic ammunition, which doesn't always generate enough pressure to reliably cycle a carbine-length gas system on its own. The shorter gas tube gives the bullet more dwell time before unlocking, which helps the action cycle cleanly whether you're running 110 grain supersonics or 220 grain subs. It's a deliberate design decision that most 300 Blackout-specific builds favor.
Yes, the 1:8 twist rate is well-suited to stabilize the full spectrum of 300 Blackout projectiles from roughly 110 to 220 grains. The pistol-length gas system helps narrow the cyclic rate gap between supersonic and subsonic loads, so you're not fighting the action as much when switching between the two. If you plan to run subsonics suppressed, an adjustable gas block is worth considering to fine-tune dwell pressure.
Standard 300 Blackout heavy-profile AR barrels in this configuration use a .750" gas block seat, which is the most common diameter and gives you the widest selection of compatible gas blocks on the market. This barrel does not come with a gas block included, so you will need to source one separately for your build.
4150 Chrome Moly Vanadium is a step above the standard 4140 alloy and was originally developed for military-grade barrels — it handles heat cycling and sustained fire better over time. The black nitride finish is a surface conversion process, not just a coating, meaning it hardens the steel itself rather than sitting on top of it. The result is a bore that resists corrosion, sheds carbon fouling more easily, and maintains dimensional consistency better than bare steel under hard use.
Yes, this barrel is designed for the standard AR-15 platform and will install into any mil-spec upper receiver. The 5/8×24 threaded muzzle accepts standard 30-caliber muzzle devices and suppressors. Just confirm your gas tube length, gas block, and handguard selection are all compatible with a pistol-length gas system before finalizing your build.
No, this is a barrel only. You will need to source a gas block, gas tube, and muzzle device separately. For a pistol-length gas system on a 16" build, make sure you're using a pistol-length gas tube to match. A 5/8×24 threaded A2-style flash hider or muzzle brake rated for 30-caliber will thread directly onto the muzzle.
| UPC | 815875019039 |
|---|---|
| Manufacturer | |
| Manufacturer Part Number | DB300P16H50B8-R |
| Length | 16" |
| Model |
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