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Best 300 Blackout Gas Systems – 2024 Buyer’s Guide

The semi automatic firing capability of any AR-style rifle is one of the features that makes it such a popular platform. Sending lead towards the target at the range as quickly as you can pull the trigger is a lot of fun. That process wouldn’t be possible without the gas system found in AR-style rifles of all kinds including ones chambered in 300 Blackout. Choosing the best gas system for your rifle can sometimes feel like a daunting task. The incorrect one will render an AR-style rifle unable to cycle the bolt carrier group properly or at all.

Keep reading to learn more and to see the best 300 Blackout gas systems on the market today!

Comparison Chart of the Best 300 Blackout Gas Systems

  • Gas Tube Pin Included
  • Stainless Steel Gas Tube
  • Compatible With Pistol-Length Gas Systems
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  • Fully Adjustable
  • Built-In Gas Regulating Gate
  • Easy to Install on Most AR-Style Rifles
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What to Watch For When Updating Your .300 Blackout Gas System

In order to maintain semi automatic firing capability, an AR-style rifle’s gas system must be working properly. The gas system allows the rifle to cycle between shots. It does this by capturing a small amount of gas from a fired cartridge as the gas travels down the barrel. It then funnels that gas back through a gas tube towards the bolt carrier group. That gas then allows the bolt carrier group to do what it needs to do. With such an important role in proper rifle function, there are a few things to look out for when shopping for a new one.

The information found below should be a fine place to gain some new knowledge as you start your journey of deciding on a new 300 Blackout gas system.

This Section Written By: Brian Belko

Expert Author

Brian is an experienced freelance writer and technical writer who has previously written for publications such as Wide Open Spaces, Bigfoot Gun Belts, Alien Gear Holsters, and Kampgrounds of America. He brings both a passion for writing and a love of the outdoors to his published content.

Aside from writing and the outdoors, Brian enjoys gardening, being a co-host on The Nostalgia Blast Podcast, and learning to code.

Size Matters

There are four main types of gas systems: pistol length, carbine length, mid-length, and rifle length. These various types refer to the length of the gas tube that is part of each gas system. It is important to get the right length for the type of rifle that you have or are building. This will be determined by both barrel length and the type of ammo being fired including caliber and powder load.

Both pistol length and carbine length systems will work with a rifle chambered in 300 Blackout. However, a carbine length gas system will have more limitations when it comes to the powder that can be used in the cartridges so that the rifle will still reliably cycle. 

CMMG Pistol Length Gas Tube

Why Is That?

This is because the longer the gas tube is, the more gas there must be to reach the bolt carrier group and provide it with enough energy to cycle. This means that a large volume of gas must be produced and not every type of 300 Blackout powder or ammo is capable of producing it. The best advice here is to go with a pistol length gas system for a 300 Blackout rifle. It offers the most versatility in what ammo can be used in the rifle including subsonic rounds while still allowing the rifle to function properly.

Spare Parts

The gas tube in a gas system is the most fragile part of the system. That isn’t to say they sustain damage or break often, but if a part is going to break it will likely be the gas tube as it is located on the outside of the rifle. Because the gas tube is fairly inexpensive, it is a good idea to buy an extra just in case. They don’t take up a lot of space and can save a day at the range or in the field in the case of damage or malfunction.

Reviews of the Best Gas System For The 300 Blackout

Below are five of the best gas systems for the 300 Blackout currently on the market as of this writing. It is important for you to look through each of these reviews carefully. There will likely be something about one of these gas systems that will catch your attention and be a great addition to your 300 Blackout rifle.

If you see one that sticks out as a possible choice, be sure to do some additional in-depth research to ensure that it is actually worth the investment. With that said, let’s get to the first on our list, the “Best Overall” gas system:

Best Overall

CMMG Pistol-Length Gas Tube

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Next, we’re going to take a look at the best gas system for the 300 Blackout for those that are currently on a budget. For that honor, we give the CMMG Pistol-Length Gas Tube the nod. This is a gas tube that is made from high-quality materials to ensure durability and longevity. At the same time, this gas tube is designed to be resistant to corrosion.

If you’re looking for a pistol-length gas tube that will work perfectly with your gas system, the CMMG gas tube might be worth the extra look. Aside from the tube itself, this comes with a gas tube pin that is designed to keep the tube itself in place.

Once installed, this will give your 300 Blackout the best in all-around reliability and performance. If you’re looking for a gas system that will suit you best and not break your bank account at the same time, then the CMMG Pistol-Length Gas Tube might be the best gas system for you and your wallet.

Bottom Line

If you’re looking for a good reliable gas tube without having to worry about sucking the life out of your bank account, there’s a good chance the CMMG Pistol-Length gas tube will be your best choice. You might have an AR-style pistol that will fire subsonic 300 Blackout rounds, so you need a gas tube that will be reliable and will aid in making it as accurate as possible.

This isn’t a “you get what you pay for” kind of gas tube, by the way. You’re getting a gas tube that will work with your pistol-length gas system and deliver a superior performance like no other. Not bad for a gas tube that is considered a “budget accessory”.


Easy to Install

Best Gas System for a 300 Blackout for the Money

Reliable for 300 Blackout Rifles that Fire Subsonic Rounds


May Not be Suitable for Use in Some U.S. Jurisdictions Due to Gun Laws

2. 2A Armament Lightweight Adjustable BCG

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For our final gas system, we’ll be looking at the 2A Armament Brand and its lightweight adjustable BCG. You’re probably wondering why a bolt carrier group, of all things, is included on this list.

Well, this BCG, in particular, has a built-in gas regulating gate. Which means that not only is this a good addition to your rifle as a possible BCG, but it also doubles as a drop-in gas system that will eliminate the need for adjustable gas blocks. If you’re looking for something that will ensure that your rifle is restored to a factory full weight, then the 2A Armament BCG might be something you’ll want.

Since this is considered a drop-in accessory, you won’t have a difficult time installing this on your rifle. The RBC of this accessory can be adjusted by way of the port door. What’s even better is that you don’t need to disassemble the rifle in order to do this.

Bottom Line

This is quite an impressive little unit. A BCG that also plays a role in being an excellent gas system for your 300 Blackout rifle. We’re actually impressed that an accessory like this can pull off quite the responsibility. If you’re looking for a BCG and want to include something that is built-in to serve as a gas system, look no further than the 2A Armament BCG as the best possible option for your 300 Blackout rifle.


Easy to Install

Eliminates the Need for an Adjustable Gas Block

Super Durable Thanks to the High-Quality Material it’s Made From


None Available

3. Brownells – 16″ 300 Blackout Barrel & Carbine Gas System Kit

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If you’re looking for a barrel and a carbine gas system in one complete kit, you’ve got it. This is the Brownells’ brand barrel and carbine gas system. The barrel is measured at 16 inches, which is compliant with most U.S. states and jurisdictions. So if you’re looking for something that you can use without ever worrying about whether or not if it’s legal to use your rifle, then you’ll want this gas system kit.

You’ll also want to get one of these for your own 300 Blackout rifle if you want to kill two birds with one stone and get a barrel and a gas system. This will save you a ton of money instead of having to buy both of these accessories separately.

The barrel twist ratio is 1:8, which is a decent enough barrel twist for those who hold a high standard to accuracy. Your 300 Blackout rifle can be a force out in the field or on the range if you want to hit targets accurately from mid to long-ranges.

The gas tube is made from durable materials and is resistant to corrosion. This also has a black nitride finish, so it will blend in quite nicely with most rifles. If you’re looking for a gas system that also includes a good, reliable barrel for your rifle, then you’ll want to go with the Brownells’ brand 300 Blackout Barrel and Carbine Gas System Kit.  

Bottom Line

The Brownells brand has proven itself worthy of the “Best Overall” title, and for a few good reasons. One of those reasons is that the gas system comes with a barrel. Not only is this an added convenience, but this will also save a lot of 300 Blackout rifle owners time and money.

This means they don’t have to find a separate barrel that may turn out to be a disappointment in the long run. Aside from that, this gas system is perfect for those who are intent on using their 300 Blackout rifle for hunting or even target practice. Should you go with the Brownells, you’re going to get a total package. In fact, you’ll be getting a package deal that is easy to install on your rifle.


Easy to Install

Aids in Delivering Excellent Accuracy

Good for 300 Blackout Hunters (Specifically Coyote and Varmint Hunter)



4. Brownells – 10.5″ 300 Blackout Barrel & Pistol Gas System Kit

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Next on the list, we’ll be taking a look at another barrel and gas system kit from the Brownells brand. This time, we’ll be looking at the 300 Blackout Barrel & Pistol Gas system kit. The differences between this and the other Brownells kit is that the barrel is measured at 10.5 inches and has a pistol gas system kit.

If you’re looking for a barrel and a gas system that you can use to fire off your subsonic 300 Blackout rounds, you’ll probably want to give this kit a try. Like the previous kit, you get the convenience of getting both a barrel and a gas system for your 300 Blackout rifle.

This comes with a gas block that is low profile and a gas tube that is finished with an extremely durable black matte finish designed to be impervious to corrosion and other damage. The barrel, as mentioned, is measured at 10.5 inches with a barrel twist of 1:8. If you’re looking to get a great deal of accuracy out of a pistol-length 300 Blackout rifle, then you’ve found it in a barrel that’s included in this very kit.

One thing to note that if you live in some jurisdictions, you may not be able to use this due to some of the gun laws in place. However, if you’re fortunate to live in places where you can own and use a rifle with a barrel that’s less than 16 inches long, you’ll probably want to give this puppy a spin on your 300 Blackout rifle.

Bottom Line

If you’re fortunate enough to live in a part of the United States where gun laws aren’t holding you back, this is obviously the best kit on the market for those who love themselves some subsonic 300 Blackout rounds. Like its 16-inch barrel counterpart, this Brownells’ kit is designed to give you an excellent upgrade for your rifle.

This kit provides you with the total package that can be easily installed on your rifle and ready to go in a matter of minutes. Once installed, you cannot wait to give this a try at the range or even out in the field.


Easy to Install

Super Accurate Shooting

Great for Subsonic 300 Blackout Rounds


May Not be Allowed for Use in some U.S. states or Jurisdictions Due to Certain Gun Laws

5. Geissele Super Gas Block (SGB)

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If you need a replacement gas block for your 300 Blackout gas system, then the Geissele Super Gas Block system might be what you need. This gas block is perfect in size to fit with most AR-style rifles, including those that will fire off 300 Blackout cartridges.

The bore of the gas block is measured at .750 inches and is easy to install on your rifle. Once installed, all you have to do is connect this to your gas tube of choice and be ready for a top-quality performance that only a 300 Blackout rifle can be able to muster.

Bottom Line

At this point, we’ve looked at gas tubes. So it’s only fair that we throw in a gas block in case you need one. We chose this gas block because it is considered to be one of the more suitable replacements compared to some of the others on the market.

Whether you’re using a pistol-length gas system or a carbine-length gas system, you’ll need a low profile gas block that will get the job done and ensure the best reliability for your 300 Blackout rifle. Your search for a gas block might just end here, should you go with the Geissele as your gas block of choice.


Will Fit With Most Gas Tubes

Fits Most 300 Blackout Rifles

Installation Process is Simple


None Available

Pistol-Length vs. Carbine-Length Gas System: Which Should You Get And Why?

There are two types of gas systems within the AR family we’ll be looking at: the pistol-length and carbine-length gas systems. So, what’s the difference between the two and which one is perhaps the best of the two? The short answer: it depends.

The long answer is it will depend on the type of 300 Blackout rounds that you fire. With that said, let’s go further into detail about each gas system along with its upsides and downsides:

Photo credit:

What is a Pistol-Length Gas System?

A pistol-length gas system is located just four inches away from the barrel of an AR-style rifle. These can handle barrels measuring up to 16 inches in length. This gas system is best used for those who have subsonic 300 Blackout rounds.

Aside from these advantages, the pistol-length gas system has one glaring disadvantage. In some U.S. states and jurisdictions, these gas systems may not be put to good use considering that rifles and guns with barrels measured at 16 inches in length are prohibited for purchase and ownership.

What is a Carbine-Length Gas System?

Carbine-length gas systems are located approximately seven inches from the barrel of a rifle. These will be effective with rifles that have barrels longer than 16 inches.

In fact, this gas system will be used on most rifles that are compliant with most U.S. states and jurisdictions. One of the disadvantages of this is that it won’t work with shorter barrels. In fact, this might be considered overkill if you’re using a carbine-length gas system for rifles that have barrels of less than 16 inches.

What Are The Components of a Gas System?

These are the main components of a gas system:

Gas Block

To begin, one of the main components of a 300 Blackout rifle gas system is the gas block itself. Without the gas block itself, the gas system itself is useless. A gas system is designed to help the 300 Blackout eject from the rifle.

High-Pressure Gas

As you pull the trigger, high-pressure gas is designed to propel the round through the barrel and send it on its way towards the target you’re aiming at. This target can be situated at either a mid-range or long-range.

Photo credit:

Gas Tube

The gas comes from the gas block and will travel down the tube and into the gas key of the bolt carrier group (BCG).

Bolt Carrier Group

Next, the BCG will unlock the chamber and move backward. And of course, the rest is routine.

How to Choose a New Gas System

Before you choose a new gas system, it’s important to know how to find a few things that make a gas system great. This will serve as a quick guide to get you through the process of choosing a gas system that’s best for your 300 Blackout rifle. This will also help you make the easy distinction between a gas system that is of good quality from those that are of crappy quality. Here is what to look for when choosing a new gas system:


Of course, the important thing to worry about is quality. This means knowing the kind of materials that are used for manufacturing the gas system itself. High-quality materials such as steel are often used for some of the elements of the gas system. For example, a gas tube may also be made from high-quality steel and finished with something like black matte. The gas tube is designed to resist almost any type of damage like corrosion.


Obviously, in order for a gas system to work, you have to install it on your rifle. It is important to find a gas system that will be easy to install without ever having to rely on the professional services of a gunsmith. Most of these gas systems will be considered to be “drop-in” systems, which means they are easy to install and will require little to no usage of tools.

Separate Parts or the Entire System?

You’ll notice that some of the gas systems that we chose for review will either consist of a kit or individual parts. If you intend on saving money, instead of purchasing parts separately, it would be wise for you to choose a kit that includes some parts that are considered essential to your rifle. As a rule, make sure it includes something like a gas tube. Other parts that may be included may either be gas blocks, barrels, or BCGs.

Aspects to Consider Before Buying

Before purchasing your new gas system, there are a few additional aspects that you should consider in order to make the purchasing process easier on you. Here are some of the most popular factors that have played a role in the decision of past buyers:


Yes, anyone in search of a gas system will usually include price as a possible factor in making their final decision. Nine times out of ten, the budget shoppers are usually the ones that place high importance on price. However, it is important that price not be the be all, end all in your decision. Be sure to check whether the quality of the gas system itself is sufficient. It is possible to get a gas system or parts that are high in quality and low in price.

Pistol-Length or Carbine-Length?

This will depend on the type of 300 Blackout rifle you might have. As mentioned, in some jurisdictions you won’t be able to use a 300 Blackout rifle that has a barrel that is shorter than 16 inches in length. So you might have no choice but to go with a carbine-length gas system.

2A Armament Lightweight Adjustable BCG

This will also depend on the kind of performance you want to get out of your rifle. Pistol-length gas systems will mostly be used for short-range or mid-range shooting while carbine-length gas systems are used for slightly longer distances.

Adjustable Gas System Or Not?

One of the things to consider is whether an adjustable gas system will work better for your 300 Blackout rifle. The function of an adjustable gas system is when you can throttle down the gas that travels through your rifle. This means you can adjust the rifle’s shooting ability with some adjustment to the gas system. Meaning you can switch from burst fire to single shot if you so choose.


Finding the best gas system for your 300 Blackout is easy if you know exactly what to look for. You may want a new gas tube or an entire system. Either way, the gas system is a must-have part that will help your 300 Blackout rifle fully function. If you’re looking for a replacement gas system, be sure to get something that includes the parts that you need, like a gas block or a gas tube. As always, be sure to do your due diligence before purchasing any gas systems or accessories that you consider to be the best possible choice for your 300 Blackout rifle.  

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