- Diamond Like Carbon (DLC)
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.
- Titanium Nitride
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 has excellent lubricity, hardness, and corrosion resistance, but those benefits can be found in other finishes. The main reason to get this finish is going to be appearance. The gold color is unique and makes a very nice contrast against the matte black of the AR15.
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 (SpikeTac.com).
Today, other finishes are much more common, all of which try to improve on the original chrome in either price or performance. In fact, chrome BCGs are somewhat difficult to find today, but worth it if you can find one.
- Phosphate
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. None of the other finishes (Nitride, DLC, Titanium Nitride, etc) will be chrome lined in these areas.
- Black Nitride
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. It is also smooth and slick which makes for smooth operation and easier cleaning.
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.
- Nickel Boron
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 bolt carrier group 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. That Nickel Boron finish is MIL-SPEC on some Army mortar tube components.
- Titanium Nitride
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 has excellent lubricity, hardness, and corrosion resistance, but those benefits can be found in other finishes. The main reason to get this finish is going to be appearance. The gold color is unique and makes a very nice contrast against the matte black of the AR15.
- Robar NP3
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.
The finish is valued for its slickness and durability. Firearms instructor John Farnam has NP3 applied to not only the BCG but also the inside of the upper and lower receivers of his custom FSM4 AR15s.
It can be difficult to find BCGs finished in NP3 and it usually requires sending yours in to Robar to be plated.
Scorpion Rifle Works recommends using any of the listed coatings, but our favorite is Diamond Like Carbon (DLC) because we feel it is the slickest and most durable. If you would like to discuss or let us know your opinion, please subscribe to our email list to learn more or share your thoughts!
