Rosco Bloodline 5.5″ 9MM Barrel

Rosco Bloodline 5.5″ 9MM Barrel


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Availability: In stock SKU: BL-55-M4-9mm-10

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Rosco Bloodline 5.5″ 9MM Barrel

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

This Rosco Bloodline 5.5” 9mm barrel was primarily designed for suppressed carbines/ pistols where the handguard will be ran over the rail. It will give you the flexibility of running a suppressed platform that offers the most compact size possible without sacrificing performance. Twist rates have also been taken into account in order to optimize performance for a multitude of rounds that you may also be running out of your duty/ concealed carry pistol in order to allow a “cross platform” ballistic familiarity.

The Rosco Bloodline 5.5″ 9mm barrel is perfect for sub-caliber carbine platforms. We have taken the time to understand the purpose for these platforms and design a barrel which will support it effectively. It is our goal to get you the performance that you seek out of these barrels whether you are running suppressed, defense ammo, sub-sonic ammo or supersonic ammo (depending on barrel length). Twist rates, and lengths have all been taken into account when we set out to make these barrels.


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 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.

Product Information

Manufacturer: Rosco Manufacturing
Series: Bloodline
Profile: Medium
Part #: BL-55-M4-9mm-10
Caliber: 9MM
Length: 5.5″
Material: 4150 CMV
Finish: Black Nitride
Twist Rate: 1:10 inches
Muzzle: 1/2 x 28 threaded
MSRP: $140.00

Additional information

Weight 12 oz
Dimensions 12 x 2 x 2 in

QPQ Nitride






Rosco Manufacturing


4150 Chrome Moly Vanadium










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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.