The Rosco Manufacturing Bloodline Barrel (brand part number BL-125-M4-556-7-C) is a 12.5-inch, 5.56 NATO AR barrel machined from 4150 chrome-moly-vanadium steel and finished in a durable nitride coating. It’s built to bridge the gap between SBR-pistol and RECCE-style builds, delivering strong precision performance for its compact size, and makes a solid foundation for an intermediate patrol-style rifle. An M4 feed ramp profile and a 1:7-inch twist round out a barrel built for reliable feeding and stabilizing modern high-velocity 5.56 loads.

Key Specifications

• Chambered in .223 Remington / 5.56 NATO.
• Measures 12.5 inches.
• Rifled with a 1:7-inch twist rate.
• Machined from 4150 chrome-moly-vanadium (CMV) steel.
• Finished with a durable nitride coating.
• Cut with an M4 profile feed ramp.
• Built to bridge the gap between SBR-pistol and RECCE-style builds.
• Suited for an intermediate patrol rifle configuration.

Frequently Asked Questions

What builds is this barrel meant for? It bridges SBR-pistol and RECCE-style AR builds, and works well as an intermediate patrol rifle.

What twist rate does it use? A 1:7-inch twist, suited to stabilize a wide range of 5.56 bullet weights.

What’s the barrel made from? 4150 chrome-moly-vanadium steel with a nitride finish.

Buy the Rosco Manufacturing Bloodline 12.5-Inch 5.56 NATO Barrel

Build a compact, precise patrol-style rifle around a barrel that bridges pistol and RECCE configurations. Order it from our Rosco Manufacturing lineup, part of our AR barrels selection, at our Lubbock, Texas gun shop for fast, direct shipping.