Rosco Bloodline 9" .300 Blackout Barrel

The Rosco Bloodline 9" .300 Blackout barrel is one of the best-kept secrets in the value barrel market. While Rosco Manufacturing doesn't carry the name recognition of some competitors, their Bloodline series barrels consistently punch well above their price point, built from 4150 Chrome Moly Vanadium steel with a melonite/QPQ finish that provides excellent corrosion resistance and bore durability.

What sets the Rosco Bloodline apart from other budget .300BLK barrels is its gas port sizing. Many manufacturers drill oversized gas ports to guarantee reliability across the widest range of ammunition and conditions, but this creates an over-gassed system that batters the bolt carrier group and increases felt recoil. Rosco has found an excellent balance — users frequently report that these barrels run reliably with both supersonic and subsonic ammunition, and many run suppressed without needing an adjustable gas block. That alone can save $50-80 on a build while reducing complexity.

At 9 inches, this barrel sits at the optimal length for .300 Blackout, achieving near-complete powder burn for maximum velocity and minimal muzzle flash. The 1:7 twist rate stabilizes everything from 110gr supersonic hunting loads to 220gr subsonic match rounds. Made entirely in the USA, the Bloodline series represents the kind of value that makes quality .300BLK builds possible on a budget without meaningful compromises.