- Alfred Mendoza
- October 31, 2021
- Reviewed by James Gangler
- June 1, 2023
Building a semi-automatic rifle from scratch requires a good upper receiver. Choosing the correct bolt carrier group that meets or even exceeds mil-spec standards and has a longer service life is essential.
This is why our team spent 48 hours looking for the best AR 15 bolt carrier group that would suit your specific needs, style, and budget!
- Provides value for your money
- Works well with various firearms
- Easy to install
- Properly staked bolts
- Best for competitive shooting
- Operates smoothly
- Best for competitive shooting
- High-quality coating
- Sharp and clean bolts
- Can handle full auto fire
- Easy to clean
- Less susceptible to fouling
- Great for tactical and practice shooting
- It comes with a tool steel extractor
- It has a shrouded firing pin
Table of Contents
- 1 Top 10 AR-15 Bolt Carrier Groups
- 1.1 1. Colt - Bolt Carrier Group
- 1.2 2. Brownells - M16 5.56 BCG Nickel Boron MP
- 1.3 3. Aero Precision BCG
- 1.4 4. Brownells Titanium BCG
- 1.5 5. Double Star - AR-15 5.56 Bolt Carrier Group
- 1.6 6. Brownells Nitride BCG
- 1.7 7. Rubber City Armory - Bolt Carrier Group Titanium
- 1.8 8. Faxon Firearms - AR-15 9mm Bolt Carrier Group
- 1.9 9. Stern Defense, LLC - AR-15 9mm BCG
- 1.10 10. JP Enterprises Full Mass Bolt Carrier Group
- 2 Factors to Consider
- 3 Our Team's Selection Process
- 4 FAQs
- 5 And The Best Bolt Carrier Group for AR-15 Is…
Top 10 AR-15 Bolt Carrier Groups
1. Colt - Bolt Carrier Group
Why We Picked It:
This bolt carrier group has a steel and black finish plus a mil-spec assembly with bolt, bolt carrier, and a firing pin. The bolt assembly is high pressure tested and magnetic particle inspected to avoid any malfunctions that may affect the gun’s performance.
This bolt carrier group is best for military and law enforcement rifles because of its full-length shroud, which can be used for tripping auto sear. The gas key is crafted for smooth cycling and is resistant to various elements to protect it from combustion from hot gases.
EDITOR’S CHOICE
PROS
- Provides value for your money
- Works well with various firearms
- Easy to install
- Properly staked bolts
- Best for competitive shooting
CONS
- Cheap finish
2. Brownells - M16 5.56 BCG Nickel Boron MP
Why We Picked It:
This bolt carrier group has a heat-treated finish and is created from a 9310 steel that can give its users flawless gun performance when operating. It has also undergone magnetic particle inspection, making the steel secured, durable, and high quality.
This BCG also comes with an extractor with an inserted rubber, spring, and staked gas key screws to prevent it from loosening.
PROS
- Operates smoothly
- Best for competitive shooting
- High-quality coating
- Sharp and clean bolts
- Can handle full auto fire
CONS
- Stiff bolts, when used
- Extreme build-up of carbon
3. Aero Precision BCG
Why We Picked It:
This product is composed of a carrier made from 8620 steel, while its bolt is from Carpenter 158 tool steel. These are also shot-peened and underwent magnetic-particle inspection to ensure their users of high-quality performance.
This bolt carrier group has a gas key (staked) and a black-nitride finish for friction reduction when operating. It is also considered one of the best bolt carrier groups in the market.
PROS
- Easy to clean
- Less susceptible to fouling
- Great for tactical and practice shooting
- It comes with a tool steel extractor
- It has a shrouded firing pin
CONS
- The firing pin could be sheared
- Short stroking
4. Brownells Titanium BCG
Why We Picked It:
Brownell’s Titanium BCG offers a bolt carrier group that is best for any lightweight rifle build. It comes at only 7.9 oz, helps reduce recoil, and has a complete package of bolt carrier groups with O-rings extractor and staked gas keys.
Their bolt carrier group is built from a 9310 tool steel and is magnetic-particle inspected to assure quality and good performance. It also has a diamond-like carbon coating to ensure the product’s durability.
PROS
- Has multiple-benefits
- Easy to install
- High-quality finish
- Clean machining
- Solid lockup
CONS
- Tight against the magazines
- Hard to release bullets
5. Double Star - AR-15 5.56 Bolt Carrier Group
Why We Picked It:
The Double Star bolt carrier group has a Parkerized mil-spec finish made from 8620 carbon steel. It also provides durability as it has a hard-chrome plated steel firing pin and staked gas key.
To elevate the quality of this product, Double Star’s bolt carrier group also went through magnetic-particle inspection. This process is done to assure their users of few to no internal flaws at all whenever using it.
PROS
- High-quality finish
- Gas keys are staked properly
- Works smoothly
- Worth the price
- Used for competitive shooting
CONS
- Requires fitting
- Has limited functions
6. Brownells Nitride BCG
Why We Picked It:
Brownells offer a complete set of bolt carrier groups made of high-quality materials that can lessen your worries and are considered to be budget-friendly. It has a bolt, firing pin, retaining pin, cam pin, bolt carrier, and gas key that is fully assembled.
Their bolt carrier group is heat-treated, shot-peened, and is magnetic particle inspected to provide their users with reliable quality. Their bolt carrier is from 8620 hardened steel, while the bolt head is machined from durable 9310 steel instead of Carpenter 158.
PROS
- High-pressure tested
- Matte black phosphate finish
- Titanium nitride coating
- Corrosion-resistant
- Provides reduced friction
CONS
- Flawed quality control
- Discoloration of finish
7. Rubber City Armory - Bolt Carrier Group Titanium
Why We Picked It:
This bolt carrier group from Rubber City Armory is known for its proprietary aerospace nitride coating that doubles quality and has wear resistance. You have to take note that the BCG serves as the workhorse inside your upper, which is why this must be both reliable and durable.
This is one of the aspects where this BCG shines, as it is one of the top-rated bolt carrier groups in the market today. It has a black nitride with an enhanced finish, providing durability, corrosion resistance, and a built-in lubricant. The carrier also fits well with any AR 15 and M16 components, which means it works on various firearms.
This BCG from Rubber City Armory is considered a lightweight bolt carrier group built from 9310 steel. It also comes with a tool steel extractor and cam pins. On a side note, remember to check your cam pin often if you use them for a long time to avoid any performance problems.
PROS
- Fast test firing
- Adjustable gas block
- Less friction in the upper receiver
- Tunable gas system
- Chrome lined gas key
CONS
- Expensive
- Works only with adjustable gas block
8. Faxon Firearms - AR-15 9mm Bolt Carrier Group
Why We Picked It:
They say bigger is better, but the Faxon Firearms M16 Bolt Carrier Group might prove that untrue. This AR 15 bolt carrier group is durable, has a gas key attached to its carrier, and can surely handle anything from a couple of shots up to a full-auto fire.
In fact, it is deemed to be best for full-auto operation and has been deemed to have no significant impact on semi-auto rifles. This bolt carrier group is Nitride coated to promote corrosion resistance.
PROS
- Solve extraction problems
- Easy to remove pins
- Heat and wear resistance
- Reliable extraction
- Compatible with lower receivers
CONS
- Expensive
- Light marring issues
9. Stern Defense, LLC - AR-15 9mm BCG
Why We Picked It:
Stern Defense offers a 9mm AR 15 bolt carrier group with a Glock-pattern upper receiver and Melonite finish. You don’t have to worry because it comes with a complete set, including the cam pin and springs.
However, take note that this bolt carrier group will not function well with a full-automatic fire-control group in your pistol-caliber carbine.
PROS
- Competitive shooting
- Affordable price
- Easy to install
- Works with colt magazines
- Can handle full auto fire
CONS
- Limited functions
- It doesn't work with echo support trigger
10. JP Enterprises Full Mass Bolt Carrier Group
Why We Picked It:
The JP Enterprises is one of the top-rated and lightweight bolt carrier groups, which has a lower mass when compared to the mil-spec standards. It is made from stainless steel, which means that it is durable and of superior quality, and it has a quench nitride finish. Its amazing build also makes it corrosion-resistant.
Our team picked this bolt carrier group because it limits the felt recoil for fast follow-up shots. It also comes with an extra-wide carrier rail for wear resistance and a bolt alignment. The manufacturers also made sure that the bolt carrier keys were staked with a dust cover notch feature.
PROS
- Stainless steel bolt
- Omitted forward assist serrations
- Lower reciprocating mass
- Extra-bearing carrier rails
- Worth the price
CONS
- Quite expensive
- Requires compatibility
Factors to Consider
Type
Full Auto
A full-auto bolt carrier group has a lug that causes increased mass remains of your bolt carrier and assures fully automatic fire. Its steel BCG is heavier than the semi-auto because of the additional metal that improves stability, making it a more reliable bolt carrier group in the market.
Semi-Auto
Unlike the full-auto, the semi-auto bolt carrier group has no lugs that hinder owners from using the BCG effectively in full auto operations. It is also lighter and comes with a smooth cycling action and increased accuracy. However, it has high recoil and muzzle rise that may affect your bolt and may cause it to bounce when using it.
Read: Full Bolt Auto Carrier vs Semi-Auto
HPT & MPI Tested
The High-Pressure Inspection (HPI) test is the process of purposely testing over-pressured cartridges to make sure a bolt carrier group can handle higher pressures without causing any troubles.
On the other hand, the Magnetic-Particle Inspection (MPI) test refers to the process of ensuring that there are no cracks in the barrel to avoid accidents during the operation [1].
Coatings & Finishes
Nitride
Nitride, also known as melonite, is present on bolt carrier groups with a black finish. It makes the surface hard enough to resist wear and corrosion. It is the usual finish that bolt carriers have. Many users want it because of its advantages though it is not mil-spec for BGCs.
Nickel Boron
Nickel Boron finish coating has high resistance, low coefficient friction, and has corrosion resistance [2]. It is one of the most famous bolt carrier group finishes in the market as it works better in contrast to Chrome or Nitride. Nickel Boron finish is also best if your upper receiver is black because of the sharp look it gives off.
Chrome
Chrome is another bolt carrier group finish that increases durability, helps prevent corrosion, and is wear-resistant. They say that it is easier to clean compared to other finishes like Phosphate. Chrome is hard to find nowadays in the market and is considered to be more expensive.
Titanium Nitride
A Bolt carrier group with titanium nitride coating or anodized aluminum decreases their weight and mass. It also has hardness and corrosion resistance. This kind of material is for military applications, which can help upgrade maintenance and edge retention.
This also makes your bolt carrier group look unique because of its gold color, unlike the others with a black finish.
Parkerized Manganese Phosphate
The military rifles have a phosphate finish for their mil-spec bolt carrier group. Users say that it holds the oil well when used in operation. It is also an advantage in the military setting because it is less shiny.
Chrome line gas keys are also inside the bolt carrier, which is not present in other finishes.
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Shrouded Firing Pin
Having a shrouded firing pin on your bolt carrier group will prevent your firing pins from being stressed and overly used as they get a break every once in a while. Full-auto bolt carrier groups often come with a firing pin when you purchase them, which many users prefer because it is more reliable.
Materials & Construction
Bolt carrier groups are from different materials. The most common that you will see in the market are made from steel because having a heavier steel BCG increases the gun cycle. There is also aluminum, but its durability is low. On the other hand, Titanium is a lightweight BCG but is more costly when compared to steel.
Mil-Spec
A mil-spec bolt-carrier group means it met the minimum requirements to perform heavy duties in the shooting range. Mil-spec bolt carrier groups are chrome lined and are from 8620 and 9310 steel. They also come in a fully assembled set with bolt, gas tube, lugs, extractor, adjustable gas system, and the necessary pins.
Durability
“Bolts are heat-treated to attain the final mechanical properties.” – Reed Miller, Metallurgical Engineer.
You will know the durability of an AR 15 bolt carrier group once it undergoes the process of HPI and magnetic-particle inspection. These tests ensure that it has no flaws or damaged particles, is wear-resistant, and has corrosion resistance too. Aside from that, a bolt carrier group is heat-treated for proper gas system functioning.
Budget
There are numerous bolt carrier group manufacturers that offer affordable BCGs. Although their price is low, they still give a high-quality performance to satisfy what their users are looking for. There are also available expensive bolt carrier groups that come with a fully assembled set.
So, if all you’re after is a good performing BCG, then you can go for ones that are affordable yet high quality. If you have a few bucks to spare and want one that comes with a fully assembled set, there are many available options in the market for you.
Our Team's Selection Process
Overall Performance
Our team spent hours researching and testing each bolt carrier group mentioned above. We included the bolt carriers with high-quality performance, made from superior materials, magnetic-particle, and high-pressure inspected to ensure their durability is secured. These are also the ones that have established a good name and reputation in the firearms industry.
Weapon Compatibility
You need not worry because our team can assure you that the entire bolt carrier group mentioned above is compatible with AR15 and M16 rifles. They are measured to fit your match-grade guns, so you will not encounter any issues with their fit.
Product Quality
The products on our list are based on the positive feedback of the customers after purchasing and testing each bolt carrier group. These BCGs made it to the top of our list because of their proven performance, good reputation, and sturdy build. These are also some of the brands that come highly recommended and have received good to excellent ratings.
FAQs
Based on our research, Colt makes the best AR-15 bolt carrier group. Their M15 5.56 BCG has properly staked bolts, ensured durability because of the quality inspections it goes through that will protect your bolt from hot gases combustion.
Yes, a BCG with Nickel Boron coating is worth it for an AR 15 bolt carrier group. It is silver and shiny, aesthetically pleasing, has no friction, and has heat dissipation benefits. Aside from that, Nickel Boron requires just a bit of lube, making it very easy to clean.
Yes, you can use any bolt carrier in an AR 15 rifle. The entire bolt carrier group on this list is interchangeable with any standard rifle. Doing so can also help fine-tune the characteristics of your rifle when shooting. However, try not to overuse it to avoid wear and tear.
And The Best Bolt Carrier Group for AR-15 Is…
After 48 hours of extensive research, our team has decided that the best bolt AR-15 bolt carrier group is the Colt – Bolt Carrier Group. This BCG has a black finish, and a high-pressured and magnetic-particle inspected bolt assembly, resulting in a good product that promotes durability and quality.
It comes with a gas key that helps in smooth cycling and resistance that can help protect your firearm from hot gasses combustion. There is absolutely no doubt that it is the best option for law enforcement rifles as it fits even the strictest military specifications.
If you are looking for the right bolt carrier group that would suit your needs and is friendly to the wallet, then the Colt – Bolt Carrier Group is the best option for you!
EDITOR’S CHOICE
Our #1 Recommendation
Colt - Bolt Carrier Group
- Provides value for your money
- Works well with various firearms
- Properly staked bolts
- Best for competitive shooting
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