Nefarious Arms HK416 / MR556 Barrel, 12.5" LIGHT, 5.56x45mm NATO
Nefarious Arms HK416 / MR556 Barrel, 12.5" LIGHT, 5.56x45mm NATO
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The Nefarious Arms HK416 / MR556 Barrel is engineered for shooters who demand uncompromising performance, precision, and durability. Proudly made in the USA, this barrel is crafted from premium 4150 Chrome Moly steel, cold-hammer-forged for strength, and chrome-lined to ensure years of reliable accuracy. Finished in black manganese phosphate, it’s built to handle heavy use while maintaining peak performance. Whether you’re upgrading your HK416, MR556, or MR223*, this barrel delivers the reliability and consistency you can trust.
Key Features:
- Caliber: 5.56x45mm NATO
- Barrel Length: 12.5"
- Profile: LIGHT
- Twist Rate: 1:7
- Barrel Extension: A1/A3 or A5
- Gas Block Seat Diameter: 19mm (h6 Tolerance)
- Muzzle Threads: 1/2"x28
- Material: 4150 Chrome Moly
- Finish: Black Manganese Phosphate
- Cold-Hammer-Forged for Strength and Consistency
- Chrome-Lined for Years of Accurate Shooting
- Weight:
- Made in USA 🇺🇸
Compatible With:
- HK416 A1/A3
- HK MR556
- HK416 A5 / MR223*
*Requires A5 Barrel Extension Option
Compatible Gas Blocks:
- Nefarious Arms NA5 Adj. Gas Block
- HK A1/A3
Note:
A5 Barrel Extensions are marked "HAUS" due to an error by the barrel extension supplier. The marking is not visible once installed.
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Let customers speak for us
from 56 reviewsShipped same day and was exactly as described! Yall are awesome! Cant wait to buy more stuff!
Heavy duty and well machined.
This company is great! Marvin is an artist, orders sometimes will take a while but rest assured when you do get it, it will be perfect, so if youre a potential customer, be patient. It will be done
I enjoyed all the products so far. I plan to purchase more products in the future, keep up the good work!
I used this tool to build a Nefarious Arms A3 IAR barrel on an MR556 upper, and it was absolutely perfect for the job. It easily held under the required torque specs with zero barrel shift. More importantly, it eliminated any worry about shearing off the index pin, ensuring near-perfect timing after installation.Before this, I attempted to use a Midwest Industries Reaction Rod but found way too much play. The MR556 platform demands tight tolerances, and a generic reaction rod simply doesn't offer the precision needed. Because this tool is made specifically for these barrels, the fit is exact. If you are doing an MR556 build, this is the tool you need.
Nothing but the best.
Wow! I'm so glad I was able to grab the last SOCOM profile 14.5 A5 barrel available for now. IMO the fit and the finish is top notch and can't be matched.
I shot nice thight groups out to 100m... so, I can't complain. Looking back, I wish, I could have gotten at least one more barrel for a future A5 project.
Alan Taylor
Dallas, Texas
Very high quality barrel. I would consider this to be as good if not better than the hk made barrels. The chrome lining is excellent and the overall fit and finish is top class. Very smooth shooting would definitely recommend if you are wanting to build a clone or just looking for a high quality cold hammer forged chrome line barrel.
Just got it last Friday so I haven't shot it yet. I purchased the barrel and had Marvin install it on an MR556A4 upper. The work looks really good (no little nicks or anything), the barrel itself is well-made and it's nice seeing a chrome-lined barrel on an HK MR carbine! Would definitely recommend Marvin's work as well as NA for offering us "civvies" a mil-spec barrel. Kudos!
P.S.- Holly answers the phones there and she was very helpful and polite. You all have a solid employee!
Very high quality and definitely adds pressure to the system.