Rosco Bloodline 10.5″ 300 Blackout



This Rosco 10.5” 300 Blackout barrel was designed for SBR and Pistol use in conjunction with suppressors. The 10.5” 300 Blackout Rosco barrel was made to be a direct replacement for any MK 18 platforms that are currently in 5.56 NATO. The 10.5” barrel is also perfect for carbines which require a slightly longer rail in order to run PEQ-15’s, D-BAL (series), or any laser aiming devices comfortably. ALL NFA RULES APPLY!

2 in stock

SKU E5B-BL-105-HB-300BLK-7-P Category Tag


These Rosco 300 Blackout barrels were created by using input from SOCOM end users and some of the original creators of this caliber. Every barrel was designed to optimize the original role for the 300 Blackout; to be suppressor friendly and accurate. It is our goal to get you the performance that you seek out of these AR15 barrels when running sub-sonic ammo or supersonic ammo (depending on barrel length). Twist rates, gas port diameters, and lengths have all been taken into account when we set out to make these. Let’s just say that we don’t like leaving things to chance.

Barrel Length 10.5″
Barrel Weight 21.4 oz
Barrel Material 4150 CMV
Barrel Caliber 300 BLK
Barrel Profile




Barrel Thread

5/8 x 24

Gas Block Size


Gas System Length

Barrel Crown

11 Degree

Barrel Finish


Barrel Extension Finish



Rosco Manufacturing


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