Bloodline 12.5” 5.56 NATO

From: $164.00

This 12.5” Rosco barrel is designed to bridge the gap between SBR-Pistol and/ or RECCE platforms and delivers amazing precision performance for its compact size. It is the perfect addition for the person attempting to create the ultimate intermediate patrol platform.

(32 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.

Out of stock

In stock

This 12.5” Rosco barrel is designed to bridge the gap between SBR-Pistol and/ or RECCE platforms and delivers amazing precision performance for its compact size. It is the perfect addition for the person attempting to create the ultimate intermediate patrol platform.

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 12.5″
Barrel Weight 21.79oz
Barrel Material 4150 CMV
Barrel Caliber 5.56
Barrel Profile




Barrel Thread

1/2 x 28

Gas Block Size


Gas System Length

Carbine Length
Barrel Crown

11 Degree

Barrel Finish


Barrel Extension Finish


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

32 reviews for Bloodline 12.5” 5.56 NATO

  1. Shane Bertrand (verified owner)

    This is my 4th barrel from Rosco. Customer service, fit, finish, accuracy, durability, etc have all be fantastic every single time I have purchased anything from them. I’ve been running a 10.5 for a while now and can’t wait to see what this 12.5 will do. #barrelgang

  2. Dan M.

    Always wanted to get around to building a Mini Recce and the 12.5” barrels that were out there lacked in performance from what I saw.

    My 14.5” Bloodline performed soo good that I decided to give this 12.5” a go, I could not be happier. I’ve been seeing 1” groups on the regular at 100 yards with 77gr TMK’s. Hope to push it out to 500 yards soon and see what it does!

  3. Dogsoldier (verified owner)

    This is my second barrel from Rosco and I don’t see myself buying from anyone else. I just took my 12.5 build out for the first time today and shot 200 rounds. Not many at this point but enough to know I made a good purchase. I have over 2k on my 14.5 Purebreed and I still get to show off its accuracy. I can’t wait to train with my teammates to show this one off also. Well balanced with consistant accuracy. It’s already my favorite.

  4. @m4gunny_ (verified owner)

    I ordered the 12.5” bloodline, while I haven’t hit the range with it I can speak to the physical quality and fitment of the parts. I got the barrel, the low pro gas block and the melonite tube. All of the fit and finish was perfect, professionally packaged and Rosco makes a product you can see the quality in by it laying on the table. I will be ordering more in the future. New favorite company to deal with. “Maybe” you can get better barrels, but for the price of the bloodlines….. goodluck matching the Roco quality to anyone else’s low price. Best “bang” for your buck I’ve seen in AR parts. Thank you guys for making a solid affordable product that will last and do what it should.

  5. Cory Yilmaz (verified owner)

    Very happy with my new rosco mfg barrel!

  6. MICHAEL MORGAN (verified owner)

    With some prompting from my son, I ordered this barrel after having problems with another 12.5″ barrel from a well known manufacturer. After several hundred rounds, I am very happy with this barrel from Rosco. The finish is very nice and this is easily the most accurate barrel within this price range. Very impressed… much so, that I just ordered another Bloodline barrel in 300BLK.

  7. Robert Elliott

    Received the barrel a week or ten days ago. I’ve been able to get it to the range a few times, about 250 rounds so far. Barrel runs great normal and suppressed. With green tip ammo it was just over an MOA. Using 1-4 optic. With MSR Fusion Ammo 62 grain, it stayed under the MOA mark. I haven’t got to shoot any heavier loads yet but I’m expecting good things. Love the barrel, would highly recommend.

  8. bill wheat (verified owner)

    AWESOME!!!!! Will run anything i put in it!

  9. Cory Haworth (verified owner)

    Haven’t tried my 12.5 barrel yet but out of the box the quality of the barrel is pristine.

  10. Kris Rodriguez (verified owner)

    Better than what I had expected with the 12.5″ and for my first build I think I made the right purchase. Shot around 250 rounds and every shot was dead on. Love this barrel and I look to ordering more in the future builds I make.

  11. Nathan Kaiser (verified owner)

    This barrel is amazing and a one of a kind product! I would recommend this barrel to anyone that is either building your own AR or just upgrading!

  12. Angelo

    Super fast shipping, awesome fit, can’t wait to take it to the range on my SBR!!

  13. Justin Duarte (verified owner)

    This is my second Bloodline barrel from Rosco and I couldn’t be happier. First one I purchased was the 10.5” and now the 12.5” for a new build and the quality is up there with the best. Definitely a customer for life

  14. rlademann83

    Rosco never fails to impress, the packaging alone is a indicator of quality. I did pick it up at BDU and saved a few bucks. Lands and grooves look like perfection. 4 stars only
    because I’ve yet to break it in due to covid19 range closers but doubt it’ll disappoint. Keep up the fine work Rosco!

  15. Levin Smith (verified owner)

    Top notch work. Machining, dimple for gas block, gas port, even the threads. All of it is quality.

  16. Phil VanDeMoortel (verified owner)

    I liked the quality of this barrel so much that I decided to purchase a second one! Can’t wait to see how well it performs in the field. With great quality and pricing over other barrels. It’s sure to be a winner!

  17. James (verified owner)

    Exactly as described. My first barrel from Rosco, and couldn’t be happier. Fast and secure shipping. Can’t wait to get range time with it!!

  18. Jason (verified owner)

    Fantastic product made extremely well and delivered quickly

  19. Jake (verified owner)

    This is a really great barrel, its everything I expected it to be and more. The shipping was really fast and the craftsmanship on this barrel spot on. This is my first bloodline barrel. It was a little tight installing into the upper receiver but it shoots excellent.

  20. Leo (verified owner)

    Good solid built barrel, also shipping was fast can’t wait for this build

  21. clentaaa (verified owner)

    Barrel is top quality and rosco puts their time into it from the packaging down to the finished product

  22. RICKO (verified owner)

    Wow, your barrels are beautiful. And your packaging is at the next level. Thank you for your fast service. Will definitely recommend to all my friends. Thanks again.

  23. Brandon Thomas

    I have picked up two 12.5” Bloodline Barrels from Rosco specifically from Primary Arms. I enjoy my first one so much i bought the second one for my second AR Pistol build as i want that compact but RECCE style rifle as it fits my needs. Definitely grab one if you are looking for a 12.5” hard use barrel.

  24. Connor (verified owner)

    Fantastic fit, well machined! Shoutout to flannel daddy for mentioning it in one of his videos, thats how I found out about Rosco!

  25. Jared Wright

    I’ve had my 12.5 barrel for over a year now and it’s easily my favorite and I take it everywhere. I’ve shot well over 1k rounds through it and at first I wasn’t sure about it but after breaking it in the accuracy improved and I was hooked on Rosco barrels! Can’t beat them I’m about to pick up a 10.5 for another build.

  26. Jerry booher (verified owner)

    What can I say been buying rosco barrels a long time and it just keeps getting better and better my 12.5 is at 1moa at 100 keep putting out those bangers guys can’t wait for the new one to drop later!!

  27. Govan Walcott

    Only have had this barrel for about 2 weeks now and I’ve already put close to two thousand rounds through it. I was completely satisfied with every group, every impact, the accuracy, and craftsmanship of this barrel. A huge improvement from my previous barrel. I have no doubt this will be my go to barrel supplier year after year. You can’t beat the price for the performance.

  28. Matt M. (verified owner)

    This was my first Rosco purchase and all I can see is I am IMPRESSED. Now first the disclaimer, I have not checked headspace and/or installed the barrel to see how it performs in the accuracy department. With that being said, the first thing that jumped out at me was the PACKAGING. The barrel came triple boxed, with the inner box being very nice with foam padding and with the Rosco logo etc. on the outside of the box. I have never received an AR barrel in such a nice box. Fit and finish of the barrel was IMPECCABLE. Additionally, I got the usual swag one would expect such as a couple of stickers (large) etc. The bonus was a 10% off coupon for my next purchase and I will definitely be making another purchase in the future!

  29. andrewpstover (verified owner)

    My first Rosco barrel, a 12.5″ 5.56. I watched SOTAR autopsy one with 26k of full auto through it and was sold. I won’t be able to afford that much ammo in my life, so should be good to go. Fitment and finish are excellent. I’m shocked by how much you get for your dollar with this company. I’m already buying two more barrels from Rosco, an 18″ 223 Wylde and a 16″ 300 BLK.

  30. Dennis Blanks (verified owner)

    Barrel came in a day early. Very satisfied. I’m building my first AR pistol and I’m glad I chose this barrel. Can’t wait to see how it all works out

  31. Eric (verified owner)

    Such great quality for such a low price. Also happy that the barrel was dimpled for the gas block

  32. Ben (verified owner)

    This is my very first rosco barrel. My brother had bought one before me. And I was instantly sold on it’s fit and finish. And accuracy. So I decided to buy one for my 12.5inch build. I’m definitely not disappointed. Thing is a tank. The packaging is literally the best I’ve ever seen for a rifle barrel. I ALMOST liked the box in came in more than the barrel. It’s a sick box. But The fit and finish is superb. The pre dimpled gas block location is perfect. It weighs enough to let you know it’s seriously high quality, but not too heavy. 11/10 would highly recommend not buying anything else other than Rosco. No question

    I have yet to shoot the rifle with the barrel yet. But I already know it’s going to be a tack driver. Rosco is the best in the game in my opinion. I doubt I’ll ever buy another brand of barrel. I need more of these badass boxes

Add a review

Your email address will not be published. Required fields are marked *