Bloodline 10.5″ M4 5.56 NATO

From: $153.00

Bloodline 10.5″ M4 5.56 NATO: This Rosco 10.5″ M4 5.56 NATO Bloodline Barrel is designed to be the perfect addition to any SBR or Pistol build. ALL NFA RULES APPLY!

(24 customer reviews)

Melonite Gas Tubes

Our Rosco Melonite Gas Tubes have an extremely durable Black Nitride finish that increases corrosion resistance, wear resistance, fatigue strength and cosmetic appeal. These gas tubes work great under a handguard because they are more durable than standard gas tubes. Available in pistol, carbine, patrol length, mid-length, and rifle lengths. Does not include a roll pin.

Non-Adjustable Gas Block, v2

Our v2 Non-Adjustable Gas Blocks feature the same 'Bloodline' dependability, with improvements for the modern shooter.  We added a knockout hole at the front of the gas block to aide in removing the gas tube. Also featuring improved tolerances and finishes, making the v2 Gas Block a staple for years to come.

Adjustable Gas Block

Our Rosco Adjustable Gas Block is purposely designed to be lined up perfectly with our barrels and gas ports to ensure reliable cycling every time. These Adjustable gas blocks pick up where our standard block leaves off and works perfectly for shooters that want to be able to control their gas flow for suppressed applications.

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Bloodline 10.5″ M4 5.56 NATO: This Rosco 10.5″ M4 5.56 NATO Bloodline Barrel is designed to be the perfect addition to any SBR or Pistol build. ALL NFA RULES APPLY!

Our Rosco 5.56 (NATO) barrels are designed to meet the modern day carbine shooters requirements. We are a long way from our daddy’s “Sporter” AR, and those specs just won’t cut it anymore. From properly managed dwell times for SBR’s, to running Suppressed, or setting up a balanced patrol carbine we have incorporated your needs into our engineering. We have successfully accomplished this by picking the right twist rates, gas port diameters, and barrel materials according to the barrel we are making (not a lazy blanket method). We have also balanced input from our consumers and military end users in order to bring you the product you need, not just the one we want to sell you.

Barrel Length 10.5″
Barrel Weight 19.28 Oz
Barrel Material 4150 CMV
Barrel Caliber 5.56
Barrel Profile




Barrel Thread

1/2 x 28

Gas Block Size


Gas System Length

Barrel Crown

11 Degree

Barrel Finish


Barrel Extension Finish


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Browse all of our 5.56 NATO Bloodline Barrels >>

Additional information

Weight 1.5 lbs
Dimensions 19.5 × 2.3 × 2.2 in

Melonite Gas Tubes


Carbine Length

24 reviews for Bloodline 10.5″ M4 5.56 NATO

  1. SHORT GUY (verified owner)

    First let me say that the “Bloodline 10.5″ M4 5.56 NATO” barrel is top notch quality. The price of this barrel is awsome. You relly can’t beat it for the time and quality that goes into these barrels. In my opinyon if you are doing a build take a look at ROSCO and give them a try. The barrel is super clean looking and well made, its also engraved with there logo. Customer service is GREAT !! The only thing I found lacking is packaging. The packaging is fine and keeps the barrel safe in travel but it was bland. I would have liked to see some stickers or swag of some kind. In the end that doesnt really matter anyway just had to put it out there. Bottom line is Buy this barrel give them a shot!! You will not be disappointed!! THANKS AGAIN ROSCO !!

  2. Scott Miller

    I purchased two barrels for here, a 14.5in & 10.5in bloodline barrels. Shipping was Extremely Fast, which I Loved! I have purchased many expensive barrels in the past DD, Faxon, ect. But have never received a barrel like this. The barrel came in a custom Rosco Man. Box, with foam protection holding it in. A pamphlet and Rubber Rossco Patch was inside. You will love the patch! Lol The care and work that went into this barrel, let alone the packaging. Was out of this world, Excellent!! The barrel was top notch. I couldn’t believe what I received for half the cost of other top of the line barrels I have purchased. I used an adjustable gas block on mine. It has 1-7 rifling, so you can shoot anything out of this. It’s qpq coated inside and out. This barrel will shoot under 1 moa. I even shot thru the same holes with hand load ammo. This company makes great products and the people I talked to there were great, they answered all my questions I asked. I will definitely be ordering more products in the future. Thank you, For the Great Barrels & Service!

  3. JP (verified owner)

    Awesome quality barrel. Have fired just over 1k rounds and it’s been flawless. Recoil is outstanding, easy to stay on target and it cycles everything from 55gr reloads (cheap) to 75gr. Have not had a single cycling issue. I run a Geissele super 42 buffer spring with the H1. I have an extra tungsten weight to add to make it H2 but haven’t even thought about adding it because there is really no need. I zeroed it at 50 yards with three rounds groups and on my final three round group I keyholed my second round with a combined three shot group at a bit over 1/3inch . Have only taken it out to 200 yards as of this review and it’s a performer. I highly recommend this barrel. For the cost and quality it’s hard to beat

  4. Jason Ferguson (verified owner)

    I ordered the 10.5 bloodline barrel and so far I am very happy with my decision to try Rosco. Shipping was fast and on time. Their website is very user friendly which I like. Packaging was good but it would have been nice to see a couple stickers come with the barrel. Not a big deal though. I had to head back out of state for work so I only got to put 100 rounds through the barrel but it’s performance exceeded my expectations. I will definitely purchase another barrel from Rosco in the future and I highly recommend anyone looking to purchase a new barrel check out Rosco you won’t be disappointed

  5. Charles J Johnson (verified owner)

    Barrel is flawless and ordering was as easy as 123 great delivery time and again product was top notch with some great stickers and the barrel was well packaged and presented

    Well buy again in my future builds

  6. Shane Bertrand (verified owner)

    I’ve probably got about 1,500 rounds through this barrel and I can’t be happier. The gas is perfect whether you’re running suppressed or unsuppressed. The fit, finish and target crown will give just about anyone a chub. For the price and the quality, you can’t do much better. The only problem I have, is wanting every length of barrel and having to small of a safe for all the sauce.

  7. Spencer

    I have about 5,000 rounds though my barrel and still going strong. The finish still looks like the day I got it. Recommend this barrel and company every time.

  8. Cody Mullvain (verified owner)

    Quality product, manufactured by quality people. I ordered a 10.5” bloodline in 5.56 and couldn’t be happier. This company has come highly recommended by several friends of mine and I was not disappointed, in fact I was so happy I ordered their BCG, gas tube and gas block.

  9. Caleb (verified owner)

    100% excellent quality, excellent packaging, excellent communication on expected time to ship around the holidays. It’s obvious when you hold these barrels how much time and care was taken during manufacturing. I haven’t put any rounds through this 10.5” yet but I have complete faith there will be no issues. Well done dudes, well done.

  10. Max Turner (verified owner)

    Excellent product. Exceeded expectations…. awesome customer service. Thanks for great and hassle free purchase!

  11. Zane

    Best barrel for the money period.

  12. Zane

    Best barrel for the money, got all my friends using Rosco barrels in their next builds.

  13. Clint (Hoodlum)

    Bought this because I heard some hype. Figured 130 was a good price. It got to my house and I installed the barrel in my upper that had a diamondback 10 inch. Took it out, did the break in for the bloodline. Took it to 100m and shot it. Turns out, it will shoot 1inch w/ 77gr smk. So I’m blown away. Gave great groups on everything from 55 to 68 gr. I’m just blown away. I want a 16 inch pencil barrel for my rifle now. Like I really do.

  14. Mike

    What’s better than 1… 2! Used the Rosco 10.5 on both builds. I’ve used mostly noveske and BA barrels until now. Fit and finish is top notch and for the price. Can’t beat it. Barrel gang!

  15. Colin (verified owner)

    Best barrel you’re going to find for the money for m sure. Quality is right along side expensive main stream barrels

  16. Michael Arecco (verified owner)

    Best barrels I have gotten so far have been from you guys. The pre dimpling for the gas block set screw is a nice touch that I’m sure most overlook.

  17. Emery (verified owner)

    I received order quickly and the 10.5” bloodline barrel is top quality. 100% satisfied. Thank you ! Rosco manufacturing!

  18. Jered (verified owner)

    Absolutely love it! I actually didn’t know it was dimpled. Installing it was super quick and easy. Tested it yesterday everything ran smooth! ???????????????? Definitely buying another!

  19. Steven Fairbanks (verified owner)

    Very impressed with Rosco. I built a 16″ about 5 months ago for a friend that has run exceptionally well. Pressure is perfect when running range ammo, also have Superlative adjustable block to mitigate higher pressure ammo back and forth as needed. I just applied this 10.5″ with a Superlative Piston System 3 days ago, and again, pressure was right on point with no modification. They have both been accurate at 100 yards with no sporadic issues of any kind. Looking forward to going further distance and higher round count. Sweet for an outstanding price. Thank you guys for going the extra mile.

  20. Dante Farina (verified owner)

    These are top notch barrels. I’d recommend them to anyone who’s serious about their barrels.

  21. Aaron Nasarow (verified owner)

    Awesome barrels , can’t wait for the adjustable gas blocks to be back in stock . I purchased a 12.5 and a 10.5 the 12 came with a gas tube the 10 did not , I believe the 12 came from AR discounts on sale . The price for these great barrels is awesome . Next time I would like to be sure if it comes with a tube or not , just for convenience. Thank you for the great service.

  22. Chandler Larson (verified owner)

    Great barrel, adjustable gas block and tube. Well made, and excellent shipping! Doesn’t group as well as I would like but still able to get 1.5 – 2 MOA with 75gr and 68gr BTHP match ammo.

  23. Evan Wangenheim (verified owner)

    Used this for my first AR so take that how you will. But it great right out of the box. Everything was packed super well and there were no machining burrs or dust to clean off. It fit super snug to an Anderson upper with a Geissele Super Modular Rail. I also love how it came with a detent already in it to quickly and accurately line up the gas block.

  24. Jim Spicer

    I have the 10.5” Bloodline barrel on a pistol build… BA lower, Aerotek upper, Aerotek rail, with a SupArms adjustable gas block and the Noveske KX5 foaming pig muzzle device. To date I’ve run just under 700 rounds through the gun, and it’s been flawless. Accuracy is way better than I expected from a 10.5” gun… consistently 1/3” groups at 100 yds, and averaging around 1.5-2 MOA at 300. Inhabe a BA 12.5” upper that I’m seriously considering swapping barrels on, putting in a 14.5” Bloodline and doing a P&W NOX muzzle device to make it a legal 16”. Thanks Rosco for making a super high quality barrel at a very reasonable price!

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