The AR15 is a popular platform for a variety of shooting applications, from hunting and sport shooting to law enforcement and military use. The Bolt Carrier Group (BCG) is a critical component of the AR15, responsible for chambering and extracting rounds and cycling the firearm’s action. The best bolt carrier group coatings can enhance its performance, durability, and longevity, making it an essential upgrade for serious shooters. In this article, we’ll explore the different types of coatings available for the AR15 BCG and highlight the benefits of the Rankin Industries SP4 Coated Bolt Carrier Group.

1. Phosphate Coating

Phosphate coating is one of the most common and widely used coatings for AR15 BCGs. This coating is typically applied through a process called Parkerizing, which involves soaking the BCG in a solution of phosphoric acid and manganese or zinc. The result is a thin layer of iron, manganese, or zinc phosphate that provides corrosion resistance and lubricity.

Phosphate coatings are relatively inexpensive and easy to apply, making them a popular choice for many manufacturers. However, they are not particularly durable and can wear off over time with extended use. Phosphate coatings are also susceptible to rust and corrosion if not properly maintained.

2. Nitride Coating

Nitride coatings, also known as Melonite or QPQ coatings, are a popular alternative to phosphate coatings.  There are lots of trade names to this type of coating.  Nitride coatings involve immersing the BCG in a salt bath of nitrogen and carbon at high temperatures, which results in a surface layer of nitride or carbide. This coating provides excellent wear resistance and corrosion protection, making it a popular choice for people that shoot a lot of rounds and military applications.

Nitride coatings are also harder and more durable than phosphate coatings, making them less susceptible to scratches and wear. However, they can be more expensive than phosphate coatings and are not as widely available.

3. DLC Coating

Diamond-like carbon (DLC) coatings are a type of thin-film coating that provides excellent hardness and wear resistance. DLC coatings are applied through a process called physical vapor deposition (PVD), which involves depositing a thin layer of carbon onto the surface of the BCG. The resulting coating is extremely hard and wear-resistant, making it an excellent choice for high-stress applications.

DLC coatings are also highly corrosion-resistant and provide a low coefficient of friction, which enhances the BCG’s overall performance. However, DLC coatings can be expensive and are not as widely available as other coatings.

4. Chrome Coating

Chrome coatings are a popular choice for AR15 BCGs due to their excellent corrosion resistance and hardness. Chrome coatings involve electroplating a layer of chromium onto the surface of the BCG, which provides excellent wear resistance and lubricity. Chrome coatings are also easy to clean and maintain, making them a popular choice for military and law enforcement applications.

However, chrome coatings can be more expensive than other coatings and can add weight to the BCG. They can also be brittle and susceptible to cracking under high stress or impact.

5.  SP4

SP4 coatings are quickly becoming more and more popular for those seeking the very best in coatings for AR15 Bolt Carrier Groups.  SP4 offers the best in durability of all the coatings.  It is also ranked as #1 in flexibility, slick coefficient, ease of cleaning and maintaining.

This is the extreme in BCG coatings.  It is extremely thin, and that means there is no thick substance to interfere with normal operations.

When SP4 is used on full auto BCG it increases the cycle rate due to the slick coefficient of the coating.  This product is simply amazing.

 

The Rankin Industries SP4 Coated Bolt Carrier Group

After careful consideration of the different types of coatings available for AR15 BCGs, we have determined that the Rankin Industries SP4 Coated Bolt Carrier Group is the top pick. The SP4 coating is a proprietary coating that includes all the features that any enthusiast would want.

The SP4 coating provides excellent wear resistance, corrosion protection, and lubricity, making it an ideal choice for high-stress shooting applications. The coating is also highly durable and scratch-resistant, ensuring a long service life for the BCG. In addition, the SP4 coating provides a low coefficient of friction, which enhances the BCG’s overall performance and reliability.