Diamondback DB Barrel (M4 Contour) — 5.56x45mm NATO, 16", Black Nitride, 4150 Chrome Moly Vanadium Steel | SKU: 556C16MF50B8R (UPC: 815875019060)
Upgrade your AR-15 with the Diamondback DB 16" M4-Contour Barrel, engineered for dependable accuracy, long service life, and easy integration with standard AR-platform components. Built from 4150 Chrome Moly Vanadium (CMV) steel and treated with a black nitride (QPQ) finish, this 5.56 NATO barrel delivers outstanding wear resistance, corrosion protection, and a slick bore that cleans up fast. The familiar M4 contour balances weight and heat management for a do-everything carbine that handles well on the range, on the ranch, or at training classes.
Why Choose This Diamondback 16" M4-Contour Barrel?
Proven 4150 CMV Steel: A duty-grade alloy selected for heat tolerance and durability under high round counts.
Black Nitride Finish: QPQ nitride hardens the surface, resists rust, reduces fouling, and supports consistent velocity over time.
M4 Contour Balance: Keeps weight forward of the receiver manageable while providing material where heat is most concentrated.
5.56 NATO Chamber: Run 5.56 NATO or .223 Rem (per manufacturer guidance) for flexible ammo sourcing and reliable function.
Build-Friendly: Designed for AR-pattern uppers and compatible with standard components for straightforward assembly.
Key Features at a Glance
Caliber: 5.56x45mm NATO (accepts .223 Rem in most 5.56 chambers; follow manufacturer guidance)
Length: 16 inches
Profile: M4 contour
Material: 4150 Chrome Moly Vanadium (CMV) steel
Finish/Treatment: Black Nitride (QPQ) inside and out for corrosion and wear resistance
Platform: AR-15 / AR-platform
Model / SKU: 556C16MF50B8R
UPC: 815875019060
Color: Black
Notes: Thread pattern, gas system length, gas port size, and twist rate can vary by production. Always verify these specifics with the retailer or Diamondback’s product page to ensure compatibility with your intended muzzle device, gas block, and ammunition.
Performance Benefits You’ll Notice
Consistency Over Strings: CMV steel plus nitride helps the bore resist throat erosion, supporting stable velocities and groups as round counts climb.
Smoother Cleanup: The nitride-treated bore reduces copper and carbon adhesion, cutting down your time on the bench.
Heat Management: The M4 contour smartly places steel where it’s needed, maintaining balance without unnecessary weight.
Versatile Use: Equally at home in general-purpose carbines, class guns, and range builds when matched with a quality bolt and ammo.
Ideal Build Use Cases
General-Purpose Carbine: Reliable all-around performance for training, practice, and everyday tasks.
Modern Accessory Setups: Pair with free-float handguards, weapon lights, and optics without turning the front end into an anchor.
Upgrade Projects: Replace a worn or mystery barrel with a known 4150 CMV, nitride-treated performer.
What You’ll Need to Complete Your Build
Gas system components (gas block + gas tube matched to the barrel’s gas system length)
Barrel nut & compatible handguard
Muzzle device (verify thread specs before purchase)
Quality bolt carrier group (properly headspaced)
Charging handle and upper receiver (AR-15 pattern)
Installation Tips
Inspect & Degrease: Clean extension and journal surfaces; lightly oil to prevent galling.
Torque Correctly: Follow barrel nut torque specs and use the right tools to avoid receiver damage.
Gas Block Alignment: Center the gas port and secure per the block’s instructions (set screws dimpled/pinned as applicable).
Headspace Check: Confirm with the appropriate gauges before live fire.
Season the Bore: A short, disciplined break-in and proper lube help maximize long-term consistency.
Specifications
(Exact twist rate, gas system length, and muzzle thread pattern should be confirmed before ordering parts.)
Frequently Asked Questions
Q: Is .223 Rem safe to use?
A: Most 5.56 NATO chambers are designed to run both 5.56 and .223 Rem. Always follow the manufacturer’s written guidance and use quality ammunition.
Q: What twist rate is it?
A: Twist can vary by run. Verify the exact twist (e.g., 1:7 or 1:8) on the product listing or with Diamondback before pairing with specific bullet weights.
Q: What’s the gas system length?
A: Many 16" barrels use mid-length or carbine systems; confirm on the listing so you can purchase the correct gas tube and block.
Q: Is the barrel chrome lined?
A: This model is black nitride (QPQ) treated, not chrome lined. Nitride provides a hardened, corrosion-resistant surface and low-fouling characteristics.
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Build a reliable, accurate AR-15 foundation with the Diamondback DB 16" M4-Contour 5.56 NATO Barrel—a nitride-treated 4150 CMV workhorse that balances durability, weight, and value for a carbine you’ll actually enjoy shooting and maintaining.
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