If you’re a true rifles fanatic and prioritize personal defense safety, you’d realize the cruciality of maintenance and upgrading works of your rifles. Most often than not, the checking of the condition and lifespan of your 300 bolt carrier group tend to be overlooked.
It’d be as simple as simply checking and upgrading the individual components of your bolt carrier group to ensure the whole BCG to increase its lifespan and improve performance of your rifles.
Lucky for you, we have an article and section on the best 300 blackout BCG you can break down and get your hands on the BCG within the market. We’d list down the complete buyers guide and the available bolt carrier groups which are offered by the manufacturers in the market.
What Is A Bolt Carrier Group (BCG)?
The bolt carrier group can be found in any semi automatic rifle or even pistol. The bolt carrier group acts as a product that provides the fundamental and central action mechanism of your rifles. The bolt carrier group also allows your firearms hammers to be reset and houses the bolt.
Additionally, the BCG is an essential part of your AR15. The bolt carrier group is situated at the upper receiver, which allows your AR15 to function at its maximum capacity and capability. Not to forget that the bolt carrier group also allows your gun to be considered a semi automatic rifle in nature.
The List of Parts of Bolt Carrier Group
1. Bolt Carrier
It is common to use the phrase “bolt carrier” and “bolt carrier group” interchangeably.
However, there is indeed a difference between these two phrases that reviews often do not explain. Firstly, the “bolt carrier” consists of an individual component which is responsible for holding other components of the bolt carrier group BCG together. Besides that, “bolt carrier group” refers to the complete new bcg.
The bolt carrier is often made of sturdy materials such as hardened 8620 or 9310 steel which are extremely durable and reliable. These materials can be responsible to reduce force which is emitted from the pressurized gas upon firing each round. Also, the material could help you to reset the hammer quickly and easily within your AR15 upper receiver.
2. Carrier Key
The carrier key is in fact, the gas key which is situated above your BCG. The gas key has a hollow opening to allow it to fit perfectly over the gas tube within the upper. Upon firing a round, the gas key will proceed in receiving pressurized gas from the barrel chamber that runs through the gas tube.
Then it functions by using this force to ensure the action of the rifle throughout the BCG.
3. Bolt and Extractor
The bolt and extractor is a metal-faced gear which is positioned right in front of the BCG. The force derived from the bolt and extractor which comes from the new cartridges loaded enables the ejection of old shells from the magazine to the chamber.
The extractor works by securing itself onto the cartridge’s rim then it proceeds to extract the spent cartridge shells after being accumulated within the chamber. Note that the bolt will strip a cartridge from the magazine and inject into the chamber.
4. Firing Pin
You may be familiar with a firing pin but regardless, the firing pin is activated when the hammer hits on it then would come in contact with the primer upon pulling the trigger which causes an explosion.
This high pressure process would spark the gunpowder within the cartridge to ignite and combust. In turn, you’d witness gas to be expanded, pressurized and heated to high temperatures that would propel the bullet towards the direction it is directed. Later on, the firing pin would span over the bolt’s length while the head of the firing pin heads towards the front.
5. Cam Pin
The cam pin is better known as the bolt cam, this is a rather small component of the BCG but carries a significant function and role to keep rounds to be fired safely and efficiently. The cam pin functions and triggers when pressurized gas is entered into the carrier key which would be channeled into the gas chamber.
The cam pin would force an internal rotation within the bolt carrier during a rearward motion to unlock the bolt from the chamber and allow the rifle to cycle.
The cam pin would similarly rotate once again during a rearward motion but it would lock the bolt onto the barrel chamber this time around. This would create a seal which is extremely tight that protects the person shooting the rifle and avoid the rifle to bolt blowback.
The high pressure which carries force of 50,000 – 60,000 PSI of dangerous piping hot pressurized gas which are located inside the barrel chamber but this time, it’d explode and propels towards the BCG and the person who fired the shot.
How Does the Bolt Carrier Group Function?
Now, we have fully understood the parts of the bcg as stated above. We shall discover the mechanism of a BCG to fully understand its capacity and ability before going into the reviews below.
Every single time you proceed to fire a shot from your AR 15, pressurized gas is emitted from the spent round and is channeled down the gas tube and all the way down to the bcg’s carrier key. This pressurizing force accumulated from the spent cartridges would fill up the gas chamber and head directly to the bolt’s tail and this in turn, causes the bcg to propel backwards.
During this rearward motion, the bolt cam is triggered within the bcg and this would unleash the bolt from the rifle chamber. Thus, creating the entire bcg to rearwards and compress the buffer spring of your rifle.
The bolt carrier would travel to the rear then the extractor would be hooked onto the cartridge’s rim, which pulls the spent casing into the ejection port, discarding the spent casing from the firearm in its entirety. The hammer of the bcg would be secured on the rearward stroke to produce the first half of the action cycle of the bcg.
Once the mag is ejected, the buffer spring which is being compressed would send the bcg forward motion. Later on, as the bcg goes back to its initial default position, the bolt strips a cartridge from the magazine and chambers the round. During this, the cam pin will rotate the bolt and lock into the barrel chamber where a tight lipped gas seal is produced
In absence of a fully-functioning bcg, your AR-15 will not be considered as a semi-auto rifle and would require manual cocking after every shot being fired.
Top 4 Best 300 Blackout Bolt Carrier Group Review in 2022
Let’s dive into the list of the best 300 blackout bcg which are currently available on the market offered by the manufacturers bcgs.
1. 2A Armament AR15 Regulated Bolt Carrier Group
Specifications
- Carrier: 8620 steel, heat treated, QPQ Nitride
- Bolt: 9310 steel, heat treated, MP, Cryo’d, QPQ Nitride
- Rear body: 7075-T6, hard anodized clear
- Extractor: machined, heat treated, QPQ Nitride
- Carrier key: machined, heat treated, QPQ Nitride, staked screws
- Regulating gate: machined from 6AL-4V Titanium
- Weight: 7.9oz assembled
- Requires customer supplied T-6 Torx tool for adjustment
Features
This 2A Armament AR15 Regulated BCG is one of the best bolt carrier groups that you can possibly buy which is crafted to perfection. This BCG is very lightweight, standing at barely reaching 8oz which would ensure perfect shots to be fired and longer shelf life.
This bolt carrier group is fully adjustable which comes with an adjustable screw which makes adjustment super easy and fast. As for the installation, it is relatively easy to install this bolt carrier group because this bcg is a drop-in unit.
The ease of installation would ensure customer satisfaction as you’d easily assemble this bcg yourself at the comfort of your own home without requiring or spending money on engaging a gunsmith.
As for the durability, this bcg has undergone tremendous testing to ensure the quality and performance is ensured. Plus, the bolt carrier group is made of 8620 Alloy, 7075-T6 and 9310 heated treated steel to increase its toughness and durability.
Regardless, the unique-selling point of this product is the adjustable titanium gas gate which allows gun owners to tune the gas system of your AR 15. This feature would allow a longer lifespan of your low mass bcgs and avoid excessive gas to be released when suppressed.
This bcg can shoot heavier bullets but maintain steadiness and stability which improve the overall range experience.
You will like this product if:
You like adjustability. The adjustable titanium gas key would ensure top quality performance.
You want ease of installation. This bolt carrier group is a drop-in unit which means you can assemble this bcg yourself and does not require any gunsmithing skills unlike most of the bolt carrier groups. This form of bolt carrier group would save you a great amount of time, energy and effort.
You might not like this product if:
You are on a tight budget. The features are relatively comprehensive but the price of this bolt carrier is rather steep which does not appear reasonable among the gun deals. So, if you’re really tight on budget, continue searching because this may not be your best bolt carrier to go for given your circumstances.
2. 2A Armament Lightweight Bolt Carrier Group
Specifications
- Cartridge: 223 Remington, 5.56 mm NATO, 300 AAC Blackout
- Carrier: 8620 steel, heat-treated, QPQ Nitride
- Bolt: 9310 steel, heat-treated, MP, Cryo’d, QPQ Nitride
- Rear body: 7075-T6, hard anodized clear
- Extractor: machined, heat-treated, QPQ Nitride
- Carrier key: machined, heat-treated, QPQ Nitride, staked screws
- Regulating gate: machined from 6AL-4V Titanium
- Weight: 7.9oz assembled
- Requires customer supplied T-6 Torx tool for adjustment
- Product of the great state of Idaho, MADE IN THE U.S.A.
Features
The 2A Armament – AR-15 BGG is proven to be lighter weight than most of the available 300 blackout bolt carrier groups. As for the installation, it is relatively easy to install this BCG because this bcg is a drop-in unit.
The ease of installation would ensure customer satisfaction as you’d easily assemble this bcg yourself at the comfort of your own home without requiring or spending money on engaging a gunsmith.
As for the durability, this bcg has undergone tremendous testing to ensure the quality and performance is ensured. Plus, the rear body of the bcg is made of 7075-T6 aluminum which is made from high-quality aircraft grade. This makes the bcg to be extremely durable and tough to withstand high pressure exhibited from your .300 Blackout rifle.
Note that every component of this bcg is heat-treated, shot-peened and crafted from high-quality 9310 steel to improve wear resistance and strength of the overall bcg.
As for those who’re searching for a gas block for your 300 blackout, the search might have come to an end. This is because this 300 blackout bcg is engineered to be fitted perfectly into your 300 blackout’s gas system.
In addition to that, this BCG manufactured by 2A Armament is incredibly versatile because it is compatible with various other parts of the firearm. The amazing versatility is observed as various types of buffer springs, suppressors and even barrel lengths are compatible with this bcg.
As for those who choose to adjust their bcg, you can easily do so through the port door of the BCG without the hassle of disassembling your 300 blackout.
You will like this product if:
You don’t like to disassemble your rifle. The impressive feature of this 2A Armament – AR-15 BGG is hassle-free and convenient without requiring any disassembling procedure.
You want ease of installation. This bolt carrier group is a drop-in unit which means you can assemble this bcg yourself and does not require any gunsmithing skills unlike most of the BCGs. This form of bolt carrier group would save you a great amount of time, energy and effort.
You might not like this product if:
You are on a tight budget. The features are relatively comprehensive but the price of this BCG is rather steep which does not appear reasonable among the gun deals. So, if you’re really tight on budget, continue searching because this may not be your best bolt carrier group to go for given your circumstances.
3. Anderson Manufacturing – M16 5.56
Specifications
- Cartridge: 223 Remington, 5.56 mm NATO, 300 AAC Blackout
- Finish: Black
- Made in the USA
- 9310 steel bolt
- 8620 steel carrier
Features
Moving on, the Anderson Manufacturing – M16 5.56 BCG has been long-established to possess high durability among other bolt carrier groups. The quality of the bcg is ensured by using 9310 steel for the bolt whereas the carrier is made from 8620 steel.
This bcg is heat-treated, short-peened, a chrome-lined interior and comes with black manganese phosphate finish. Through this, this bcg is less prone to corrosion and rust resistance for an extended period of time.
As for versatility, the Anderson Manufacturing – M16 5.56 BCG is compatible with most of the 300 rifles. Furthermore, if you’re looking for a bcg to complement and supplement your mid-range long shooting, this bcg would be the best to avoid the rounds being jammed up.
The Anderson Manufacturing – M16 5.56 BCG is a drop-in 300 Blackout BCG. Therefore, this bolt carrier group can be assembled at home as this bcg does not require any gunsmithing skills unlike most of the bolt carrier groups. This form of bolt carrier group would save you a great amount of time, energy and effort.
Additionally, in terms of aesthetics, the Anderson Manufacturing – M16 5.56 BCG features a sleek and clean design of the matte black phosphate finish which could easily complement the outlook of your .300 Blackout rifle as well. This BCG can function well in full auto and hence, the pin is shrouded.
If you are looking to build your own 300 Blackout rifle on an AR-15 platform with a tight budget, this BCG is well suited for you because it ensures your range shooting to be effortless and enjoyable each time even in bad weather climates.
You will like this product if:
You are on a tight budget. If you are building a .300 Blackout rifle on a budget, the Anderson Manufacturing – M16 5.56 BCG will still work fine without any issues even after you’ve fired a few hundred rounds.
You want a versatile and drop-in BCG. The Anderson Manufacturing – M16 5.56 BCG was designed to be compatible with most AR-15. Therefore, you won’t have to worry about compatibility issues if compared to other manufactured bcgs.
You might not like this product if:
You don’t want to adjust the gas keys. Unfortunately, some gun owners have displayed dissatisfaction on the gas key of the bcg as the gas key needs to be properly staked from time to time.
4.Toolcraft Logo’d Left Handed 5.56 Nitride MPI Full-Auto
Specifications
- Nitride Finish
- 9310 Steel Bolt
- Shot Peened Bolt
- Mag particle inspected
- Gas Key Hardened to USGI Specifications
- Gas Key Grade 8 Hardened Fasteners
- Gas Key Staked Per Mil-Spec
- Tool Steel Extractor
- Extractor Spring
- Extractor O-ring Insert
Features
As for bcgs, Toolcraft has been one of the best bcg manufacturers within the bcg’s market for its durability, reliability and quality bolt. This bcg is constructed out of heat treated 9310 steel, which is approximately 7% stronger than the more commonly available 158 carpenter steel used in most BCGs.
This bcg has a full-on nitride finish and is certified to be MPI tested for the best quality control and protected against wear resistance and corrosion from external factors. This bcg has been graded to withstand full auto fire hence, it is inevitably to be more powerful and stronger than the standard AR 15 bcg and should be able to withstand heavier grain bullets of 300 AAC Blackout easily.
You will like this product if:
You are a left-handed person. If you are left-handed then this would ensure the ease of handling or if you’re right handed person but looking for an ambidextrous option.
You want a gas key feature. The AToolcraft Logo’d Left Handed 5.56 Nitride MPI Full-Auto Bolt Carrier Group is accompanied with Hardened gas key via USGI specifications.
You might not like this product if:
You are a right-handed person. This aspect is pretty rigid and unwelcoming but the bcg is only crafted and suited for left-handed people so only left-handed rifle configurations are available.
Frequently Asked Questions (FAQs)
What is the difference between full-auto and semi-auto bolt carrier groups?
The difference between full auto BCG and semi automatic BCGs is that full auto is equipped with a rear lug which allows the function of pushing the sear release into a downward direction. In turn, this allows the firearm to fire in full auto or shocking burst fire mode As such, it is cheaper and very lesser in weight where some is even known as lightweight BCG.
What are the different coatings of bolt carrier groups available?
There are many different coatings being manufactured, but each coating has a different role and function so be sure to be well-versed before purchasing a specific bolt carrier group.
Mil-spec means there is a coating of phosphate, matte in nature and may appear slightly bumpier than the usual. Be vary that mil-spec bcg is excellent and serves its function but may require more maintenance works in terms of cleaning than other coating.
On the other hand, the black nitride coating is shiny in nature and gives a sleek black nitride finish. The nickel boron finish is relatively easier to be cleaned, silver and shiny in nature as well.
Besides this, there is also titanium nitride finish which is gold and very aesthetic. This titanium finish is very easy to be cleaned but may be harder to get in the market.
What does it mean to be HPI and MPI tested?
HPI indicated the .300 blackout BCG is high pressure tested whereas MPI stands that the BCG is magnetic particle inspected. A .300 blackout bolt carrier which is magnetic particle inspected proves that it has undergone thorough inspection and testing against any potential issues of the surface on ferromagnetic metals.
Hence, being magnetic particle inspected means that the BCG has undergone checks for any potential structural damage such as cracks, laps or inclusions that would affect the performance of your machine gun so magnetic particle inspection is very crucial