Rosco Manufacturing Bloodline 5.56 AR-15 Barrel Government Carbine - 12.5"

Manufactured by Rosco Manufacturing
SKU: BL-125-M4-556-7-C
MPN: BL-125-M4-556-7-C
Manufactured by Rosco Manufacturing
14 Reviews
Add to cart for sale price $94.99 $124.00

In Stock

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The National Firearms Act regulates the configurations of some firearms assembled with barrels under 16” long. Know the NFA laws in your state before purchasing this item.

The AR-15 is by far the most dominant carbine on the market. To stand out, simply building 'good enough' components doesn't cut it. The Bloodline series of barrels was designed and built entirely in-house by Rosco Manufacturing with the sole purpose of providing you with a barrel that will not only outperform the competition but outlast it too.


  • 12.5" Government contour
  • Carbine length gas system
  • 1/2x28 threading with 11-degree crown
  • 1:7 twist flexible round selection
  • 41V50 Chrome Moly Vanadium steel
  • Corrosion resistant salt bath nitride finish
  • Slick nitride-finished M4 barrel extension
  • Compatible with standard .750" gas blocks
  • 5.56 NATO chamber

Rosco Manufacturing takes their barrels seriously. Rather than entrust someone else's blanks or machining, they produce every barrel from scratch, controlling every step of the manufacturing process. The Bloodline series is cut from high-strength 41V50 Chrome Moly Vanadium steel, the same stuff chosen for the rifles used by our military for its exceptional durability. Improving on the military-grade barrels, the Bloodline-series are finished with a highly corrosion resistant, low friction salt bath nitride treatment, making cleaning easier than ever. By producing these barrels entirely in house, they've also been able to tune each barrel by selecting the optimal twist rates, gas port diameters, dwell times, and materials according to the needs of each barrel.

This 12.5" barrel is machined to a balanced Government contour, offering a solid balance between rigidity and weight. The reliable carbine-length gas system ensures your rifle gets the right amount of gas to cycle even in adverse conditions. The 5.56 NATO chamber is fully compatible with .223 Remington ammunition, with a 1:7 twist rate that is perfect for heavier, precision-oriented cartridges, but is thoroughly functional with popular and less expensive bullet weights.

Rosco Manufacturing got their start producing high quality, hard-use precision rifle barrels. They have since expanded, offering their own line of serious use parts and accessories so you can assemble a rifle that doesn't just shoot good and look good, but will handle hard use as well. To top it off, they're production facility is in Central Falls, Rhode Island so you know that every component is 100% made in America, by Americans.
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Barrel CoatingSalt Bath Nitride
Barrel ContourGovernment
Barrel Length12.5
Barrel LiningSalt Bath Nitride
Barrel Material41V50 Chrome Moly Vanadium Steel
BrandRosco Manufacturing
Caliber Gauge5.56 NATO
Feed RampsM4
Gas Seat Diameter.750
Gas System LengthCarbine
Thread Pattern1/2 X 28
Twist Rate1:7
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 go to

Ratings & Reviews

14 reviews

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Top Notch First impressions (not test fired)

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Barrel installed easy came in great condition and quality seems fantastic. Best part is **Barrel is dimpled from factory! I always dimple my barrels so the gas block has a lower chance of walking off or rotating - this made my life so much easier!



I was at a brothers house saw ad an got one. Built it shot an fell in love with this so much so came back for another but was sold out. I will get another for sure came fast as promise you got a customer now.

Pistol build

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I saw this barrel on sale and decided to try one. I have used Ballistic Advantage,Stoner and others. Great looking and well made. I hope that it shoots as great as it looks, I know it will out shoot me. Just completed my build and looking to getting to the range. I'm happy I found PA,I will be making more purchases in the future. Thanks

Excellent Customer Service!!

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I haven't shot through this barrel yet but I want to take a moment to praise PA for their excellent Customer service. FedEx lost my package and PA sent a replacement out to me within days after I reported it. No questions asked. Without a doubt, the rest of my build will come from PA.

Rosco Bloodline 12.5” barrel

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Really nice barrel for the money. Bought 2 already. Straight Shooter!

Awesome Barrel for the Price!


Really enjoying my 12.5” Bloodline from Rosco Manufacturing. Installed my first one on my first AR Pistol Build about a month ago and loved it so much i bought another one for my new AR Pistol Build. Definitely grab one if your in the market for a 12.5” barrel!

Bang for your buck.


So roscoe is an oem supplier. Who started selling barrels under their own brand. I haven’t shot it but upon initial inspection and installation into an aero upper it has the makings of good barrel. Finish is wonderful and even. The were no toolingmarks any where. And the threads in the end of the barrel were smooth tried three different muzzle devices before I settled on an linear comp. has a factory dimple for your gas block some premium barrels don’t have that. It fit the upper so tight i had to heat it up with a hair dryer when i dry fit the barrel before actual assembly. When I did final assembly I had to tap it in, probably didn’t need restating compound but it’s on there anyways. I have high hopes for accuracy considering the fit barrel to receiver. Anyways bag for your buck caught mine on sale.

Sweet barrel

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This barrel is everything that I wanted especially at this price. I haven't taken it out past 50 yards, but the groupings I have experienced with this barrel at that range are no more than 3/4 in. I believe with better ammo and some sand bags I could dial it in to 1/2 in. The build, with this barrel, has become my favorite and this is my 5th build. I would recommend this barrel for anyone wanting to build an ar pistol.

Proper gas port size


My biggest concern was that the gas port would be drilled 1/4" to run all kinds of weak ammunition. With a Springco blue spring and a standard carbine buffer, the first 500 rounds ejection pattern was 4:00 and slowly walked to 3:00. An H buffer replacment has kept it at 4:00 since.
@50yrds w/ 62gn 5.56 resulted in .75MOA.

Awesome, greatly made.

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This is an awesome barrel, very accurate and a quality barrel. I sold my 10.5 to get this and don't regret it 1 bit. I would definitely recommend this item.