Nefarious Arms HK416 / MR556 Barrel, 14.5" LIGHT, 5.56x45mm NATO
Nefarious Arms HK416 / MR556 Barrel, 14.5" 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: 14.5"
- 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: 27.1 oz.
- 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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Excellent option for the MR556A4 and 416 clones.
For those who don’t already know, you CANNOT do better than Marvin’s barrels. Or pretty much anything Marvin makes. Spend some money, buy his stuff, own great sh*t.
Let customers speak for us
from 45 reviewsVery 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.
Excellent option for the MR556A4 and 416 clones.
Marvin and his products are top notch. Perfect fitment, excellent quality. These are the best barrels outside fo factory HK that one can buy!
For your barrel nut torquing a must have precision made tool. Excellent machined quality to use on a number of AR , KAC , Centurion Arms or HK variants.
Nicer than other popular and similar tools I have. protect your barrel extension index pin! Get one!
Great part. Will install on my next build.
Excellent Quality, fast shipping what more could a man ask for. Thank you as always.
Quality is absolutely stellar. Nefarious arms nails it everytime
Quality is absolutely stellar. Nefarious arms nails it everytime