Bloodline 14.5″ M4 5.56 NATO

From: $171.00

This Rosco 14.5″ M4 5.56 NATO Bloodline Barrel was built around the M4 platform and is designed to be the next evolutionary step in the series. This barrel is perfectly suited for your next patrol or duty carbine build. ALL NFA RULES APPLY!

(10 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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14.5″ M4 5.56 NATO Bloodline Barrel: This Rosco 14.5″ M4 5.56 NATO Bloodline Barrel was built around the M4 platform and is designed to be the next evolutionary step in the series. This barrel is perfectly suited for your next patrol or duty carbine 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-15, 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 rifle barrels you need, not just the one we want to sell you.


Barrel Length 14.5″
Barrel Weight 26.34 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


Browse all of our 5.56 NATO Bloodline Barrels >>

Additional information

Weight 2 lbs
Dimensions 19.5 × 2.3 × 2.2 in

Melonite Gas Tubes


Carbine Length

10 reviews for Bloodline 14.5″ M4 5.56 NATO

  1. 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!

  2. Shane Hull

    I have a 14.5 5.56 and a 10.5 300blk barrel. These barrels are hands down the absolute best the industry has to offer. I am not sure of others shooting habits, I tend to run my guns harder than the average. Thousands of rounds later and I am an absolutely satisfied customer for life! Thank you Rosco for making a superior product we can trust and afford!!!

  3. Nicholas Trout (verified owner)

    Got this for a my first build and would have to say it’s just as accurate if not more than my ss barreled .308. I love this thing

  4. Jayson Robinson (verified owner)

    I research everything, Rosco was the name that kept coming up. I was not disappointed when I received this barrel. Excellent quality, premium packaging, perfect for my first build.

  5. Chris Ryan

    This 14.5 is one accurate barrel. Great quality and great customer service!!

  6. Yaniv Oshri (verified owner)

    Product came quick shipped and packed well in a nice box barrel inside the box was well protected as well. Appreciate the set screw location on back of gas port to place gas block/fsb finish of barrel is also very good . Still building and yet to shoot but well worth the price . I would highly recommend

  7. Josh (verified owner)

    All my builds are Rosco, and with quality to price ratio like they offer they always will be. Fit and finish is beautiful, packaged so dang well I hate to ever toss the barrel boxes!! I have not tested all the builds I have with Rosco barrels but everything I have tested has been excellent. Look no further than Rosco and ignore the naysayers, you’ll be happy you did.

  8. Brantley A (verified owner)

    I own an 11.5″ and two 16″ rosco bloodline barrels, i am building this next 14.5″ for a rifle which i will pin and weld myself. Rosco will always be my first choice in barrel as use them in 3 gun competitions, hunting, and training. I have always recommended rosco to new shooters as i believe that their barrels are the best quality and price.

  9. Devon G (verified owner)

    This barrel is so well made the attention to details is amazing! I installed this on my Diamondback DB-15 and it’s flawless!

  10. Vincent Vasquez (verified owner)

    Extremely well made looking and feeling barrel. Superior finish to my current Aero barrel which was shocking since I’ve been using Aero for years now. Can’t wait to get out to the range and see this beast can do.

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