Rosco Manufacturing Bloodline 10.5″ 300 Blackout Barrel (1/7 Twist)

Original price was: $162.00.Current price is: $146.00.

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SKU: BL-105-HB-300BLK-7-P

Product Description

This Rosco 10.5” 300 Blackout (300 BLK) 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 that require a slightly longer rail in order to run PEQ-15’s, D-BAL (series), or any laser aiming devices comfortably.

Rosco’s 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 Rosco’s 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: Heavy
  • Twist: 1/7
  • Barrel Thread: 5/8 x 24
  • Gas Block Size: .750
  • Gas System Length: Pistol
  • Barrel Crown: 11 Degree
  • Barrel Finish: Nitride
  • Barrel Extension Finish: Nitride




Technical Information

Color / Pattern


4150 Chrome Moly Vanadium





Firearm Compatibility

Barrel Twist


Thread Pitch

5/8 x 24


.300 AAC Blackout

Catalog Location

California Prop 65 Warning

WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information visit