SIONICS Bolt Carrier Group for .223/5.56- NP3

Original price was: $229.95.Current price is: $219.95.

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Product Description

Complete Bolt Carrier Group – HP/MPI Tested – Carpenter 158 NP3 Coated Bolt and NP3 coated Cam Pin – With the use of Ned Christiansen’s OCKS (Optimized Carrier Key Screws).

  • 100% HP/MPI Tested
  • Shot Peened
  • Sprinco 5-Coil Heavy Duty Extractor Spring
  • Black Insert
  • Nickel PTFE Carrier

SIONICS Bolts are manufactured from Carpenter 158® Steel. Each Bolt is HP/MPI Tested and Inspected. Each Bolt is Shot Peened and comes with a Sprinco Heavy Extractor Spring and Black Spring Insert. The Bolt and Cam Pin with the exception of the Extractor have been NP3 treated to enhance Corrosion Resistance and Carbon build-up.

SIONICS M16 profile Bolt Carriers are machined to USGI specifications. The M16/M4 carrier includes a Mil-Spec Gas Key. The Gas Key is heat treated per USGI specifications and NP3 Coated. The Gas Key is secured to the carrier via OCKS (Optimized Carrier Key Screw) and properly staked using a MOMOAKS. These properly hardened parts insure a strong staking and proper gas system function. Furthermore, the mating surface between the carrier and the gas key is

Each Carrier Assembly is treated with a durable Nickel/PTFE plating which creates a permanently lubricious surface that reduces the need for lubrication.

NP3 has a coefficient of friction as low as .07-.1 according to test standards LFW-1 and ASTM D-2714. Nickel Boron has a coefficient of friction as low as .08-.2. NP3 has PTFE also known as Teflon® co-deposited in the nickel matrix. As wear occurs, new PTFE particles are exposed and the self-lubricating properties continue. Nickel boron has a surface with many high points. Because the high points make all the contact, there is less surface area for friction to occur. The problem with this is once the high points wear down the coefficient of friction increases due to more surface area being contacted. With no self-lubricating particles like Teflon® in the Nickel Boron matrix, there is no additional lubrication after the contact points are worn. The bottom line is that if you see wear on Nickel Boron, it has lost its “Self Lubricating” properties at that spot.

Regarding cleaning, NP3 is easy to clean for the same reason that a pan with Teflon® is easy to clean. Teflon® is non-stick and easy to wipe down, therefor carbon does not adhere to the surface. Nickel Boron has many ridges to catch carbon fouling. The ridges in Nickel Boron are smaller than the ridges in Manganese Phosphate that act as a sponge for oil, so compared to Manganese Phosphate, Nickel Boron is easier to clean. This is the same as comparing a railroad spike to a nail in your tire. One is definitely worse than the other, but both will impede function.

Regarding Corrosion Resistance, NP3 has great corrosion resistance twice the amount of Nickel Boron. Nickel Boron is at the same level of corrosion resistance as regular Nickel or Chrome.

Note from manufacturer:

“In our opinion, there is NO comparison between an NP3/Electroless Nickel PTFE Coated Surface and Nickel Boron Coated Surface. After coating tens of thousands of Bolts and Carriers with NP3 over the years, we have NEVER seen one flake. That cannot be said about Nickel Boron Coatings. Close to seven years ago, we were provided the following information which has always proven to be accurate.”


Due to the inherent nature of NP3 Coating, Tooling Marks may be present on SIONICS NP3 Coated Bolt Carrier Groups. Tooling marks are COSMETIC and have ZERO effect on function. Being that the NP3 Coating impregnates into the host material, it is much thinner and much less forgiving in hiding Tooling Marks. Other popular coatings such as Phosphate and Nitride are thicker and darker in appearance, allowing for Tooling Marks to be easily concealed. Regardless of Tooling Marks present on SIONICS NP3 Bolt Carrier Groups, every SIONICS Bolt Carrier Group is backed by our Lifetime Warranty that covers any Manufacturer Defect that would effect function.





Technical Information


Carpenter 158




5.56 NATO / .223 Remington

Firearm Compatibility

Catalog Location

California Prop 65 Warning

WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information visit