Best Gas System For A 300 Blackout: Power And Accuracy

Many gun owners simply purchase the weapon of their choice based on reviews, suggestions of gun shop owners and friends, as well as their own personal budget. However, when you start getting down to the details behind the accuracy and power of your gun, you can’t ignore the variances in gas systems and how they work to provide the force of your choice of ammunition.

When planning an AR style build for your 300 Blackout, you want to consider the gas system you choose to provide a reliable, and accurate power source. Below we’ll explain the variances of systems you may want to consider, and which of the best gas systems for a 300 Blackout exist. 

Here’s A Quick Look of Our 5 Best Gas Systems For 300 Blackout

How A Gas System Works

300 Blackout Gas Systems

When you first start exploring various gas systems for your AR build, you may run up against the terms: direct-impingement or piston-operated gas recoil systems. For a 300 BLK you want to focus on a piston-operated system as it helps you avoid having to modify your barrel or upper, and is designed to work with both subsonic and supersonic rounds. 

These systems are responsible for firing, ejecting, and chambering the next round, and replaces the need for a manual bolt, providing semi-automatic firing capabilities. A piston-operated system captures the hot gas escaping the barrel, but instead of sending it down the barrel (like a direct-impingement system does) it is captured in a piston located in its own tube. The benefits of this include not having as much of a mess to clean your barrel, but it also may allow you adjust for fine tuning related to various caliber rounds and accuracy. 

Gas System Lengths Defined

Finding the best gas system can be a bit of a challenge with a 300 Blackout build. This is because it is created to work with a large range of ballistic options, widening the band of performance to accept everything from a .223 to .300 WM in both subsonic and supersonic options, depending on your preferences. 

Changing up barrel lengths can make this even more complicated when accuracy and efficiency is required, and adjustments on your gas system need to be understood. But, the rule of thumb to follow concerning these details isn’t hard to understand as long as you know what systems and barrel lengths are compatible.

First off, you are going to choose between either a pistol length or carbine length system, despite other lengths existing. These lengths describe how far from the chamber the gas port is, and in general you want your port to be located approximately at half the range. Pistol lengths are 4 inches long, while carbine lengths are 7 inches long. 

Pistol VS Carbine Length Gas Systems

gun at the top of the wood

This means a pistol length system is best for up to a 10 inch barrel lengths, although they can be used with longer barrels for less powerful, subsonic ammunition. Carbine length systems are best for rifles that have a barrel length between 10 and 18 inches, and work well for both subsonic and supersonic rounds. This is especially true if you plan on using a suppressor.

The downfall of using a carbine length option with anything less than a 16 inch barrel includes running into possible cycling problems, unless you are always using a suppressor. So take care when considering the cabine option with shorter barrels.

Downfalls of using the pistol length option include being overgassed for supersonic rounds, although it will still be reliable and simply shoot a bit more ‘dirty’ overall. If your barrel is anything less than 16 inches, or you plan on changing out barrels, a pistol length might be best, especially if you include an adjustable block.  

Top 5 Gas Systems For 300 Blackout Reviews

A gas system is compiled of various parts. These include the block, tube, and bolt carrier group (BCG)- and whereas you can buy the parts separately, it is sometimes best to buy them as a complete kit for easier installation and compatibility. However, the choice is yours and so we have various products below for you to consider. 

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

BROWNELLS - 16" 300 BLACKOUT BARREL & CARBINE GAS SYSTEM KIT
  • Parts Included: 16” barrel, gas block, tube, roll pin and screw set
  • Used With: an AR- style build

This is a decent carbine length gas kit and barrel combination that makes your build easier. The 16 inch barrel has a 1:8 twist for mid to long range accuracy, and is made from a 4150V Steel with a nitride finish. Included in the kit is a .750″ low profile gas block, carbine gas tube, and roll pin. It also includes the screw set for easy mounting.

The low profile design is perfect for fitting under the free-floating handguard of your choice. The gas tube also has a durable, black nitride finish for both aesthetics, and durability. This makes your build extremely convenient and saves you the trouble of having to decide which parts are best together when you buy each separately. It also has a great price point. 

Who This Is For

This is a great kit for a rifle length 300 BLK build. It takes the guesswork out of the entire gas system and comes with a compatible barrel. 

PROS

  • Great for a 300 BLK build
  • Kit includes almost everything you need for the entire gas system
  • Considered an easy install

CONS

  • May be slightly undergassed

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

BROWNELLS - 10.5" 300 BLACKOUT BARREL & PISTOL GAS SYSTEM KIT
  • Parts Included: 16” barrel, gas block, tube, roll pin and screw set
  • Used With: an AR- style build

Like their longer carbine length gas system kit, Brownell’s Pistol Length Gas Kit includes a 4150V Steel with a nitride finish barrel measuring 10.5 inches, opposed to 16 inches. It also has a 1:8 twist for accuracy and mid to long range targets. Included is a .750″ low profile gas block, carbine gas tube, and roll pin. It also includes the screw set for easy mounting.

The low profile design is perfect for fitting under the free-floating handguard of your choice. The gas tube also has a durable, black nitride finish for both aesthetics, and durability. This makes your build extremely convenient and saves you the trouble of having to decide which parts are best together when you buy each separately. It also has a great price point. 

Who This Is For

This is a great kit for a pistol length 300 BLK build. It takes the guesswork out of the entire gas system and comes with a compatible barrel. 

PROS

  • Great for a 300 BLK build
  • Kit includes almost everything you need for the entire gas system
  • Considered an easy install

CONS

  • Headspace will have to be checked with the bolt

3. CMMG – Ar-15 Gas Tube Stainless Steel

CMMG - AR-15 GAS TUBE STAINLESS STEEL
  • Parts Included: gas tube and roll pin
  • Used With: All AR-style builds

The gas tube is an important, yet simple and affordable part of the entire gas system. It carries and releases the gases, so it needs to be durable and dependable. Made from stainless steel the CMMG gas tube is one of the best in the industry for AR style builds and comes in pistol, carbine, mid-length, and rifle lengths for perfect customization. 

Made from a long-lasting, strong stainless steel, the tube also comes with the installation roll pin. Resistant to corrosion, it is the best for long-lasting reliability and performance. The pistol and carbine tubes measure 6 3/4 inches and 9 ¾ inches respectfully. 

Who This Is For

When you need a part that can be used in a variety of lengths, either to trade out an existing piece or upgrade to a new shooting experience,  this is an excellent choice.

PROS

  • Solid build with no fit issues
  • Easy to install with no alignment needed
  • Made specifically for 300 BLK needs

CONS

  • None, this is about as perfect a gas tube you can buy

4. Superlative Arms LLC – Ar-15 Adjustable Piston System .750″ Clamp On Gas Block

SUPERLATIVE ARMS LLC - AR-15 ADJUSTABLE PISTON SYSTEM .750" CLAMP ON GAS BLOCK
  • Parts Included: Piston block assembly, carrier, tools for installation
  • Used With: Rifle length AR builds

This is a ‘bleed off’ gas piston system for the AR platform that avoids restricting gas flow by allowing it to bleed out the block. Made for a carbine length 300 BLK, it also is available in piston,mid-length, and rifle length, and is designed to help reduce the overall feel of the recoil as it pressure builds only enough to drive the bolt carrier. However, it is NOT designed to use with piston length barrels. 

The gas adjustment screw doesn’t directly block the gas flow, so it doesn’t wear and corrode, nor is there any carbon build-up. This is a very different design than many others as the screw typically restricts gas flow, making this choice a long-lasting and more durable one. 

Who This Is For

If you need a gas system for a rifle length build, this is a choice well worth making. The unique gas bleed off design allows less recoil and a steadier aim. 

PROS

  • Works flawlessly
  • Easy to install and looks great
  • Reduces glas blowback

CONS

  • Will be undergassed if lengths are not lined up

5. Prime Weaponry – M16 Bolt Carrier Group

PRIME WEAPONRY - M16 BOLT CARRIER GROUP
  • Parts Included: carrier, bolt, pin, key, has key and fasteners
  • Used With: AR15 and M16 Builds

Made from 8620 Steel and  9310 Vac-Arc Premium Carburizing Steel, this carrier and bolt has hard core hardness and is considered more durable compared to how many others are made. It also includes a nitride coating to create the strongest plate possible. 

Created for consistent use for efficient wear, it is both AR15 and M16 build compatible. This is a truly unique piece in that it is fully responsible for semi-automatic firing as it quickly and efficiently chambers a new round. To avoid jamming and quick re-fire capabilities, you want the best in the business. 

Who This Is For

If you use your weapons regularly for any reason, this is the type of product you need. The material is long lasting and the toughest out there. 

PROS

  • Incredibly durable and efficient
  • Excellent price point
  • Good looking with a nice finish

CONS

  • Not chrome lined
  • May need breaking in to move more smoothly

Conclusion

Gas system builds need to be approached with the results you want in mind, or you may end up sifting through literally hundreds of pieces trying to find what works best for your gun. Barrel length, shooting style, and personal preference all play into the parts you choose. 

Although a kit may be a great choice to take the guesswork out of mixing and matching certain pieces, they might not be all what you were looking for- driving you to pick and choose from various other options. The choices we’ve provided, albeit limited overall, provide you some top picks and brand names to help you get started.