Rosco Manufacturing Bloodline 14.5" 5.56 NATO M4 Barrel – Carbine-Length Gas
The Rosco Manufacturing Bloodline 14.5" M4 Barrel (BL-145-M4-556-7-C) is the hard-use, "mil-spec plus" heart for your next carbine build. While Rosco offers a mid-length version, this specific carbine-length gas system model is designed for those who prioritize the legendary reliability and aggressive cycling of the original M4 platform. It is a perfect choice for clone builds or duty rifles where positive extraction and consistent bolt velocity are non-negotiable, even when the rifle is dirty or under-lubricated.
Machined from 4150 Chrome Moly Vanadium steel, this barrel features the classic M4 Government profile, providing a balanced feel that isn't overly front-heavy. The bore and exterior are treated with a Black Nitride (Salt Bath Nitride) finish, which creates a surface harder than traditional chrome lining without the accuracy-robbing inconsistencies often found in chrome-plated bores. With a 1:7 twist rate optimized for heavy duty rounds and an 11-degree target crown for precision, the Bloodline series delivers match-grade potential in a combat-ready package.
Important NFA Note: This barrel is 14.5 inches long. To reach a non-NFA legal length of 16 inches, a muzzle device must be permanently pinned and welded to the threads. All NFA rules apply.
Key Features
- Carbine-Length Gas System: Provides the classic, high-reliability gas pressure needed for positive cycling in all conditions.
- 4150 CMV Construction: Built from heavy-duty military-grade steel designed to withstand high heat and sustained fire.
- Black Nitride Finish: Superior corrosion resistance and surface hardness both inside and out for an extended service life.
- Optimized Twist: 1:7 twist rate is specifically chosen to stabilize 62gr, 69gr, and 77gr duty and match projectiles.
- M4 Profile: Features the iconic "grenade launcher" cutout for a traditional aesthetic and balanced handling.
- In-House Precision: Every Bloodline barrel is manufactured from start to finish at Rosco's facility in Rhode Island, USA.
Product Specifications
- Brand: Rosco Manufacturing
- Series: Bloodline
- Caliber: 5.56 NATO
- Barrel Length: 14.5 Inches
- Profile: M4 / Government
- Gas System Length: Carbine-Length
- Gas Block Diameter: .750"
- Twist Rate: 1:7"
- Muzzle Thread: 1/2x28 TPI
- Material: 4150 Chrome Moly Vanadium
- Finish: Black Nitride
- Weight: 25.86 oz (1.61 lbs)
- MPN: BL-145-M4-556-7-C
- UPC: 181969500043
