Best AR15 BCG Finishes

Best AR15 BCG Finishes

AR15 Bolt Carrier Groups

AR15 BCG finishes (l-r) Toolcraft Titanium Nitride, BCM BCG with Robar NP3+, Toolcraft Nickel Boron, Toolcraft Black Nitride, Colt BCG refinished in Chrome with Nickel Boron Gas Key, Toolcraft Diamond Like Carbon (DLC) Finish, Toolcraft Chrome Phosphate

There are a wide variety of finishes available for AR-15 bolt carrier groups (BCGs) and we take a look at some of the best and most popular ones below.

Hard Chrome

Colt BCG with matte chrome finish and nickel boron gas key

The first AR15 bolt carrier groups were hard chrome plated. This was at the direction of Eugene Stoner, the designer of the AR-15. Chrome is a finish well suited to the harsh environment where the bolt carrier group operates. Chrome is extremely hard which makes it very wear resistant. It also has high corrosion resistance as well as a natural lubricity. Chrome BCGs are available today, but other finishes are much more common, all of which try to improve on the original chrome in either price or performance.


Toolcraft 556 NATO Chrome Phosphate BCG

Toolcraft BCG with Manganese Phosphate finish

Current mil spec for bolt carrier groups in military rifles (M16 and M4) is phosphate. Some advantages of phosphate over chrome include it’s lower cost and less visible appearance in a military setting - less shiny. Properly manufactured BCGs with a phosphate finish will still have a chrome lining inside the gas key and inside the carrier where the gas rings ride. Some people like the rough phosphate finish for it’s tendency to “hold oil” better than other finishes. The roughness of the phosphate finish wears down to become a smooth surface on the high wear points like the carrier rails.

Black Nitride

Toolcraft 556 NATO Black Nitride BCG

Toolcraft BCG with Black Nitride finish

Also known as Melonite, Salt Bath Nitride or simply Nitride, this is a heat treating process that creates a case hardened surface by diffusing nitrogen into the metal surface. The resulting surface is extremely hard which makes it very resistant to wear and corrosion. Because nitrided bolt carrier groups do not require chrome lining of the gas key or inner areas of the bolt carrier, manufacturing costs are reduced. Black Nitride finished BCGs often have an attractive deep black finish. 

Probably because of this reduced cost factor and the quality of the Toolcraft brand, the Toolcraft Black Nitride BCG has become one of our best reviewed products with over 100 5-Star Reviews. See our Toolcraft Black Nitride BCG Review here Toolcraft BCG Review - Best Black Rifle Secret Ever? An upcoming blog article will review and compare several Black Nitride BCGs including Toolcraft, Aero Precision, BCM and Bushmaster.

Nickel Boron

Fail Zero 556 NATO Nickel Boron BCG

Toolcraft 556 NATO Nickel Boron BCG

AR-15 BCGs with Nickel Boron finish by Fail Zero (Top) and Toolcraft (Bottom)

Nickel Boron is an advanced metal finish that offers high resistance to wear and corrosion as well as having an ultra low co-efficient of friction. A nickel boron BCG will have greater lubricity and corrosion resistance than both chrome and nitride BCGs. For these reasons, it is a very popular AR-15 BCG finish. UCT Coatings of Palm City Florida applies their patented EXO Nickel Boron finish to many products including AR-15 BCGs for Fail Zero and Toolcraft.

For a detailed look at Nickel Boron see our blog post Top 3 Reasons You Might Want a Nickel Boron BCG. Also see our review of the Toolcraft Nickel Boron BCG here: Toolcraft Nickel Boron BCG Review

Diamond Like Carbon (DLC)

Toolcraft 556 NATO Diamond DLC BCG

Toolcraft BCG with Diamond DLC finish

Ionbond Diamond Like Carbon (DLC) Coating is a state-of-the-art metal finish applied through a Physical Vapor Deposition (PVD) process. It is an extremely tough, corrosion proof coating, with excellent low-friction properties. Ionbond Black DLC will not chip, crack or peel, providing you with years of reliable function and protection against wear. It is so strong that it is virtually scratch proof. It has an attractive gray graphite-like appearance. See our Toolcraft DLC BCG review here: Toolcraft Diamond DLC BCG - The Best BCG Ever Made?

Titanium Nitride

Toolcraft 556 NATO Titanium Nitride BCG

Toolcraft BCG with Titanium Nitride finish

Titanium Nitride is an extremely hard ceramic material, often used in aerospace and military applications that improves the maintenance, cleaning, and edge retention. This finish provides a unique look, and excellent lubricity, hardness, and corrosion resistance.

Robar NP3+

This Bravo Company (BCM) BCG has been refinished with NP3+ by Robar

NP3 is a proprietary finish offered by Robar Inc. It is an electroless nickel-based finish for steel, stainless steel and aluminum alloys that co-deposits sub-micron particles of PTFE (polytetrafluoroethylene), otherwise known as Teflon™, with electroless nickel. It is extremely slick while also being very corrosion resistant. It has a dull gray finish darker than chrome and nickel boron.

When it comes to finishes for AR-15 BCGs, the sky is the limit. All of the finishes listed here are quality finishes and a good BCG will work fine with any of them. What finish you select becomes pretty much a matter of personal preference. By weighing the pros and cons of each finish against your requirements and budget you will be able to make the right decision. 

For specific comparisons of black finishes (Phosphate vs Nitride vs DLC ) see here The Best Black BCG Finish - Phosphate vs Nitride vs DLC

To see 360 degree interactive views of all Toolcraft finishes see our Toolcraft Gallery

Thank you for visiting. 

May 10th 2019 David Blazek

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