Best Bolt Carrier Group Coating For AR15s

With a plethora of finishes on AR15 bolt carrier groups available, it can be challenging to find the right one that suits your needs and budget. Let's dive into the world of BCG finishes and explore their pros, cons, and recommendations.

A Parkerized or Phosphate-coated BCG of high quality performs better than a more expensive, low-cost BCG with premium coating (higher markup to sell for more money). The additional coating doesn't offer much advantage over regular options and might cause more issues.

Hard Chrome

The first AR-15 BCGs were hard chrome plated, as per the instructions of Eugene Stoner, the AR-15's designer. Chrome is a robust and corrosion-resistant finish, making it ideal for the harsh environment where the BCG operates. Although other finishes have become more common, chrome BCGs are still worth considering if you can find one.

  • Pros: Durable, corrosion-resistant, easy to clean
  • Cons: More expensive than some other finishes
  • Recommendation: Brownells Chrome Bolt Carrier Group


The current military standard for BCGs in military rifles is phosphate. It's less shiny and cheaper than chrome, making it a practical choice for military use. The phosphate finish is rough, which some people prefer as it holds oil better than other finishes.

  • Pros: Economical, durable, corrosion-resistant, mil-spec
  • Cons: Rough finish requiring more lubricant, harder to clean
  • Recommendations: Bravo Company (BCM) Bolt Carrier Group, Colt Bolt Carrier Group, Toolcraft Phosphate Bolt Carrier Group

Black Nitride

Also known as Melonite, Salt Bath Nitride, or simply Nitride, this finish is a result of a heat treating process that hardens the surface. It's smooth, slick, and easy to clean, making it a popular choice for many.

  • Pros: High durability, corrosion resistance, smooth finish requiring less lube, easier to clean than phosphate
  • Cons: Can cost more than phosphate
  • Recommendations: Aero Precision Black Nitride BCG, Toolcraft Black Nitride BCG

Nickel Boron

Nickel Boron is an advanced metal finish that offers high resistance to wear and corrosion. It's slicker and more corrosion-resistant than both chrome and nitride BCGs, making it a popular choice for many.

  • Pros: Slickness, durability, corrosion resistance
  • Cons: Can cost more than some other finishes
  • Recommendations: Aero Precision Nickel Boron BCG, Fail Zero Nickel Boron BCG, Toolcraft Nickel Boron BCG

Diamond Like Carbon (DLC)

DLC is a state-of-the-art metal finish applied through a Physical Vapor Deposition (PVD) process. It's an extremely tough, corrosion-proof coating, with excellent low-friction properties.

  • Pros: Extreme hardness and corrosion protection, smooth with low coefficient of friction
  • Cons: Expensive
  • Recommendation: Toolcraft DLC BCGs

Titanium Nitride

Titanium Nitride is an extremely hard ceramic material, often used in aerospace and military applications. The gold color is unique and makes a very nice contrast against the matte black of the AR15.

  • Pros: Smooth, hard, slick, corrosion-resistant, gold plated looks
  • Cons: Price
  • Recommendation: Toolcraft Titanium Nitride BCG

Robar NP3+

NP3 is a proprietary finish offered by Robar Inc. It is an electroless nickel-based finish that is extremely slick and very corrosion resistant.

  • Pros: Slick, durable
  • Cons: Expensive, especially since you will probably have to send yours in to be refinished


The choice of finish for your AR-15 BCG depends on your personal preference. All the finishes listed here are of high quality and will serve you well. If you want a black finish and have the budget, DLC is the way to go. For a bit of color or bling, consider Nickel Boron or Titanium Nitride.

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