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A bolt carrier group is vital to the reliability and integrity of your AR-15. It offers incredible innovation and technology, which are necessary when you want an effective and comfortable shooting experience.
Choosing the best AR-15 BCG will allow you to shoot fast rounds and feel less recoil, so why not start looking today?
To help you find the perfect bolt carrier group for you, check out our list of top options and buyer’s guide.
At a Glance: Our Top Picks for Best AR-15 BCG
- OUR TOP PICK: Aero Precision 5.56 AR15 Bolt Carrier Group
- RUNNER-UP: RISE Armament AR-15 Bolt Carrier Group
- BEST BUDGET OPTION: Spikes Tactical M16 Bolt Carrier Group
Comparison of the Best AR-15 BCGs
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What is a Bolt Carrier Group and What Does it Do?
The bolt carrier group (BCG) gives your AR-15 pistol the ability to create semi-automatic fire. The word “group” is in its name because there are eight main parts of the BCG:
Bolt carrier
Carrier key
Bolt
Bolt gas rings
Extractor
Cam pin
Firing pin
Firing pin retainer pin
All these pieces work together to harness hot gasses produced from a firing round and use them to rapidly propel a new round. The steps involved in the process are as follows:
The gun redirects gas from one round into the bolt carrier group.
The bolt carrier group unlocks.
The BCG pushes into the buffer tube and spring.
The buffer spring bounces back and sends the BCG to the upper receiver.
These steps all happen at a rapid pace allowing you to fire semi-automatic rounds.
Aero Precision 5.56 AR15 Bolt Carrier Group
What to Look for When Buying an AR-15 BCG
Even though the bolt carrier group is a relatively small part of your AR-15, this device’s quality is vital to smooth, rapid shots. Here are some things to keep in mind before you look at each of the BCGs.
Inspection Process
There are two main inspection processes that you should check for when considering a BCG: the magnetic particle inspection (MPI) and the high-pressure testing (HPT).
Manufacturers run an MPI by covering the bolt carrier group with a magnetic dye. They then apply an electrical charge and watch as the dye travels to any cracks or imperfections in the material.
Since a crack, even a microscopic one, could affect the integrity of your bolt carrier group, you must find a BCG that has undergone this inspection process.
The HPT process includes putting the carrier into a barreled assembly and firing it with a high power cartridge. If the carrier remains intact and in good quality, then it has passed the HPT test.
Material
You always want to make sure the bolt carrier group has top-notch materials so it will last for years to come. A few common durable types of steel are Carpenter 158, 9310, and 8620.
Manufacturers often use Carpenter 158 steel to create the bolt as it is incredibly strong. Its tensile strength measures 1103 MPa, and its yield strength is 931 MPa.
The 9310 steel is another common material for bolts and carriers, but it’s cheaper and not as strong as the Carpenter 158. The tensile strength of 9310 steel comes in at 910 MPa, while its yield strength is 570 MPa.
Finally, the 8620 steel is the cheapest option, and you can usually find it on the carrier, not the bolt. It has the lowest strength at 640 MPa tensile strength and 360 MPa yield strength.
Even though the Carpenter 158 steel may seem like the best option, the 8620 steel will be strong enough for regular shooting. Plus, the steel is usually heat-hardened to strengthen it.
Spikes Tactical M16 Bolt Carrier Group
Mil-Spec Bolt Carriers
If a bolt carrier group has the term “mil-spec” in the description, that means it upholds the U.S. military standards. A mil-spec BCG has the following:
Shot peening, or a finishing process that lengthens the life of the material
Grade 8 fasteners, or the most durable fasteners made of carbon-alloy steel
Chrome plating, which reduces corrosion
Carpenter 158 steel, which is the strongest and most durable material
Review of the Best AR-15 Bolt Carrier Groups
You definitely don’t want to skimp on a BCG, so finding a quality product is essential. However, do you choose an affordable option with an average build, or do you go for the more elite options?
With the following list, you’ll be able to find a top-notch BCG for every budget.
Best Overall:
Aero Precision 5.56 AR15 Bolt Carrier Group
Pros
Cons
What Recent Buyers Report
Overall, buyers were thrilled with the purchase. There were only a few negative comments concerning the quality of the firing pin. Because of that small flaw, some people recommended this BCG for beginners.
Nevertheless, most of the other customers (veterans included) were impressed with the lasting quality and stellar performance.
Why it Stands Out to Us
We love the quality build and materials of this BCG.
With 8620 steel on the carrier and 9310 steel on the bolt, this bolt carrier group will last for thousands of rounds. Plus, the machined finish lets you easily clean the BCG. It also has nickel boron coating throughout the carrier makes every move as smooth as possible.
The components of the bolt carrier group are top of the line. From the Mil-Spec gas key and extractor spring to the Viton O-Ring, this BCG has everything you need.
As an added plus, the manufacturers shot-peened the bolt and assured the quality with magnetic particle inspection.
Bottom Line
If you’re looking for a high-quality BCG at a reasonable price, the Aero Precision 5.56 is a fantastic choice. The material and overall build will give you a long-lasting product.
Runner-up:
RISE Armament AR-15 Bolt Carrier Group
Pros
Cons
What Recent Buyers Report
The recent customers do not have a single negative thing to say about this bolt carrier group. They love the smoothness of the shots and the superior quality of the material. Another popular sentiment was that the BCG helped make their AR-15 more reliable and produce slick shots.
Why it Stands Out to Us
This sleek bolt carrier group from the RISE Armament company is a great example of a high-quality product that creates smooth, rapid shots.
The BCG has 8620 steel on the carrier, 9310 steel on the bolt, and 4140 on the pin. Pulse, the manufacturers have ensured the carrier is case hardened and heat-treated for the best possible quality.
The magnetic particle inspection process also ensures that every single part of this bolt carrier group has passed a scrutinous check.
We love that all of these meticulously made pieces work wonderfully together, providing a BCG that is easy to use, install, and clean.
Bottom Line
Even though this model is not the cheapest option on the market, it is still an affordable option considering the impressive build. If you want a BCG that works well for a long time, the RISE Armament is an ideal choice.
Best AR-15 BCG for the Money:
Spikes Tactical M16 Bolt Carrier Group
Pros
Cons
What Recent Buyers Report
A few customers complained about the weight of the BCG. While Spikes calls this a lightweight bolt carrier group, it still weighs over ten ounces. Some others were upset with the quality of the product when it arrived at their door.
Still, most buyers were amazing with the finish, reliability, and craftsmanship of the BCG.
Why it Stands Out to Us
You can find affordability and quality in one package. This Spikes Tactical BCG is the perfect example of such a product.
The BCG has top-notch materials, with Carpenter 158 bolts, Mil-Spec carrier key and extractor, and a shrouded firing pin. The manufacturers tested the bolt with both a high-pressure testing process and a magnetic particle inspection to ensure quality. They also shot-peened the bolt to make the material long-lasting.
Bottom Line
The Spikes Tactical BCG lets you purchase a high-quality device while not breaking the bank. If you are looking for a lightweight product with the same durability as the heavier bolt carrier groups, consider this BCG.
Best Lightweight AR-15 BCG:
FosTech Outdoors AR-15 Complete Lite Bolt Carrier Group
Pros
Cons
What Recent Buyers Report
Again, we have a BCG that customers just love. They hardly had a negative thing to say about this FosTech product. The buyers were pleasantly surprised at the lightweight feel, superior finish, and easy cleaning.
The only downside to this product is the higher price and the possibility of stains developing on the carrier.
Why it Stands Out to Us
With the weight of your AR-15, brace, and sight, you may start to really feel the heaviness of your firearm. Add another pound (or more!) of a BCG, and you may begin to feel the strain in your arms.
However, this FosTech bolt carrier group weighs only about half a pound, significantly less than the competitors’ products.
Even with the light build, the BCG is durable with a nice nickel boron finish. The more open design makes it stylish and easy to clean.
Bottom Line
If you’re tired of adding extra weight to your AR-15, this BCG is the perfect option for you. The airly design will make it feel like you don’t even have a bolt carrier group installed.
Best AR-15 BCG Nickel Boron:
Lantac Enhanced Full Auto Style Bolt Carrier Group
Pros
Cons
What Recent Buyers Report
People were thrilled with this bolt carrier group, saying it was the best on the market. They loved the smoothness, durability, and superior materials.
Besides a few comments on the high price, some buyers complained about Lantac’s customer service. Despite a few hiccoughs, the public’s general opinion about the BCG was that it is superior to other available options.
Why it Stands Out to Us
With a high price comes high quality. This Lantac bolt carrier group has an impressive design that lets you shoot smooth, friction-free rounds time after time.
The device uses 8620 steel with a NiB electroless nickel boron coating. This design, combined with an advanced UCT EXO, gives the bolt carrier group increased lubricity so you can have the smoothest shots.
The shape of the BCG also gives you a better shooting experience. With the forward porting, the device runs cleaner. Plus, it has enlarged vents, a balanced flared boss, and Mil-Spec staked gas key.
To top all that off, you get a lifetime warranty with the purchase.
Bottom Line
If you have a high budget and are looking to buy an exceptional bolt carrier group, the Lantac BCG should be at the top of your list. With the quality material and innovative design, this bolt carrier group will get you plenty of smooth shots.
Best AR-15 9mm BCG:
Faxon Firearms Gen 2 9mm PCC Bolt Carrier Group
Pros
Cons
What Recent Buyers Report
Most of the recent buyers only had good things to say about this Faxon BCG. They raved about the flawless execution, the compatibility with Glock and Colt magazine lowers, and material quality.
The only slightly negative comment was about an incomplete package that arrived damaged. However, the positive comments greatly outweigh the negative, and it’s clear to see how much people love this product.
Why it Stands Out to Us
We love that this all-purpose BCG is ideal for all levels of shooters and various types of guns. Whether you need a powerful bolt carrier group that will serve you well in competition or you just want to enjoy a quality BCG while out plinking on the weekend, this Faxon product is right up your alley.
Not only is it ideal for a wide variety of users, but it is compatible with various system types. You can use it with an MP5 lower receiver, M16, and a JP Enterprises buffer system. The design also fits with Colt or Glock lower receivers.
Plus, if you want to take your game to the next level, this BCG can work for a fully automatic M-16.
Bottom Line
The Faxon bolt carrier group is a superior option for people looking for a smooth shot and durable materials.
Comparison Overview of BCG Types
Each bolt carrier group is unique, with its one style of finish and craftsmanship. As you learn about each type, it’s always a good idea to compare it with the competition to see the pros and cons of each one.
Nitride vs Phosphate BCG
Both the nitride and phosphate BCGs provide durability but in different ways. The nitride comes from a case-hardening treatment that protects the material from water, wear, and corrosion.
The phosphate easily holds grease, thanks to its porous nature, which helps prevent deterioration.
Nickel Boron BCG vs Nitride
Nickel boron and nitride are comparable finishes, but nickel boron has some considerable advantages over nitride.
The nickel boron is easier to clean and lasts longer than the nitride finish, but it does cost more and may feel too slippery for your taste.
Black Nitride BCG vs Nickel Boron
Where black nitride is a step up from the phosphate coating, the nickel boron takes the lead over black nitride.
Nickel boron is the leader in smoothness, reliability, and durability, even though black nitride is tough competition. The only downside is that the nickel boron is usually more expensive.
Full Auto BCG vs Semi
Both the full auto and semi-automatic BCGs are legal on an AR-15. While the full automatic BCG’s build is different, it will not turn your AR-15 into an automatic rifle.
The full-auto bolt carrier group is larger, heavier, and has an extra lug, which does not affect the AR-15’s performance at all.
Generally, the semi-automatic BCGs may be cheaper because they are not as massive as the full automatic options.
Nickel Boron vs Chrome BCG
Both of these finishes are great options. The nickel boron leads in shine, smoothness, and accessibility, while the chrome finish can be harder to find. However, the chrome offers an incomparable hardness and durability.
M16 vs AR-15 BCG
While you can use both the M16 and AR-15 BCGs in an AR-15, they do not have the same design. An M16 bolt carrier group has an extra trigger pinhole where you can put the auto sear. Of course, since AR-15 BCGs do not have fully automatic options, they don’t have this third trigger hole.
How to Disassemble a Bolt Carrier Group
You need to routinely clean your bolt carrier group to ensure it is constantly functioning correctly. To do so, make sure you follow these disassembly steps carefully.
- Remove the retainer pin with a round of ammunition.
- Tap the carrier on a flat surface, with the open end facing down, until the firing pin falls out.
- Twist the cam pin 90 degrees and pull it out.
- Easily pull the bolt out.
If you want a visual on how to disassemble a BCG, watch the video below.
AR-15 BCG Assembly
Once you’ve thoroughly cleaned each part, you’ll need to reverse what you did to disassemble the BCG. Here are some simple steps to follow.
- Put the bolt in the carrier at the 10 o’clock position.
- Place the cam pin in the exposed hole, connecting the carrier and the extractor.
- Twist the cam pin 90 degrees.
- Place the firing pin into the carrier, with the head facing away from the extractor.
- Put the retainer pin into the hole on the side of the carrier, twisting it slightly until it fits correctly.
For a more detailed explanation, check out the video below.
Conclusion
Buying the perfect bolt carrier group is an important purchase. You want to make sure you are investing in a top-of-the-line product.
Instead of diving down the rabbit hole and exploring hundreds of options that may only be subpar, start with our list of the best AR-15 BCGs. Hopefully, you’ll find the product that best suits your needs!
People Also Ask
Purchasing a bolt carrier group is not a small investment. Make sure you know the ins and outs of BCGs before buying one.
Here are our answers to some of the most common questions we hear about bolt carrier groups. Hopefully, our responses will help you make an educated decision.
How Does a Bolt Carrier Group Work?
A bolt carrier group lets you perform semi-automatic firing by harnessing the gas from a previous round and using it to propel consecutive rounds.
The gas produced from one round is usually expelled and left unused. The BCG takes advantage of that power to create a semi-automatic firearm.
Aero Precision 5.56 AR15 Bolt Carrier Group
Are AR-15 Bolt Carriers Interchangeable?
Generally speaking, yes, AR-15 bolt carriers are interchangeable. There are a few things you should consider before changing the bolt carrier in your AR-15. First, make sure you haven’t used it to fire thousands of rounds, as that can wear out the carrier.
Also, make sure that the bolt head size fits well in the new barrel. If you aren’t sure about the sizing, ask a gunsmith to be sure.
Once you know that everything fits correctly and the carrier is still in good condition, you can go ahead and use the bolt carrier on another AR-15.
Can You Use an M16 Bolt Carrier in AR-15?
Yes, you can use an M16 bolt carrier in an AR-15. If you want a fully automatic weapon, the M16 BCGs are your answer. However, just because you put an M16 bolt carrier in your AR-15 won’t make it a fully automatic weapon. Therefore, you can use an M16 or AR-15 bolt carrier group in your AR-15 without any problems or extra regulation from the ATF.
How Long Do Bolt Carrier Groups Last?
The life of a bolt carrier group can vary greatly. Some BCGs have a lifetime warranty, while others have advertised that they can last 20 years or more.
You don’t need to replace a bolt carrier group very often since those that have high-quality material generally last for decades or at least 20,000 rounds. If you need to substitute anything, it would probably be the bolts or the ejector spring.
Does the Bolt Carrier Group Affect Accuracy?
The bolt carrier group as a whole will probably not affect accuracy. However, a well-fitted bolt could help improve accuracy.
If the head spacing is not optimal between the barrel and the bolt, this could lower your accuracy slightly. Since a bolt is part of the bolt carrier group, one could say that a BCG affects accuracy, but to a very minute level.
Who Makes Brownells BCG?
There is a lot of debate surrounding who exactly makes Brownells BCGs. Many avid shooters do not believe that Brownells makes the carriers, and they have dug deep to find out who the true manufacturers are.
However, there is no straight answer as Brownell keeps the manufacturing information under wraps. There is a theory, though, that Toolcraft makes the BCGs.
Who Makes PSA BCG?
Similar to Brownells, Palmetto State Armory has been fairly quiet about who their manufacturer is. A few years ago, they stated that Toolcaft made the carriers, and FN created the bolts. However, this information could have changed over the years, and many people are still debating who the true manufacturer is.