Rosco Purebred 10.5″ 300 Blackout Barrel

Rosco Purebred 10.5″ 300 Blackout Barrel


Rosco Purebred 10.5″ 300 Blackout barrel is designed for SBR/ Pistol use in conjunction with suppressors, and as a direct replacement for any 5.56 NATO MK 18 platforms. This barrel is also perfect for carbines which require a slightly longer rail.
Availability: In stock SKU: PB-105-HB-300BLK-7-P

Gas Tubes

Gas tubes include a roll pin. (In cart discounts apply)

Gas Blocks

Low profile gas blocks.(In cart discounts apply)

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  • All NFA/ATF Rules Apply
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Rosco Purebred 10.5″ 300 Blackout Barrel

This Rosco Purebred 10.5” 300 Blackout Barrel was designed for SBR/ Pistol use in conjunction with suppressors. The 10.5” Rosco barrel was made to be a direct precision 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.

Rosco Manufacturing’s “Purebred” series is a testament to precision and quality manufacturing. We took a step back to see how we could create a barrel line that would be a culmination of all the lessons learned through years of making barrels for several OEM’s. The result is a barrel that will produce results out of the box for any shooter that is looking to take their skills above and beyond. All of our Purebred barrels are made from scratch in our Rhode Island facility and start life as a blank piece of 416R stainless steel.

Arm or Ally is proud to add Rosco Manufacturing to our wide selection of AR Barrels from Ballistic Advantage and Faxon. If you just starting to build your own custom rifle, see our growing selection of AR parts, to include receivers, bolt carrier groups, muzzle devices, and more in our AR parts department. Are you a reloader, or considering becoming one? We offer a large selection of bullets and brass to choose from.

All ATF/NFA Rules Apply – See NFA tab for details

Product Information

Manufacturer: Rosco Manufacturing
Series: Purebred
Profile: Heavy
Part #: PB-105-HB-300BLK-7-P
Caliber: 300 Blackout
Length: 10.5″
Material: 416R Stainless Steel
Barrel Extension Finish: Nickel Boron
Finish: Bead Blasted
Gas System Length: Pistol Length
Gas Block Diameter: .750″
Twist Rate: 1:7 inches
Muzzle: 5/8 x 24 threaded
Weight: 21.09 oz
MSRP: $200.00

Additional information

Weight23 oz
Dimensions12 × 2 × 2 in

Bead Blasted




300 Blackout


Rosco Manufacturing


416 Stainless Steel


Barrel, Upper Receiver Parts








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You may use this barrel with a lower receiver that is a Registered SBR, Machine Gun, or Pistol. Possession of this barrel along with a Non-NFA lower receiver is Prohibited, except when installed on a Pistol configuration firearm.