Guns

5 Best 300 Blackout Upper Receiver Groups For AR-15

A relatively new addition to the shooting world, the 300 Blackout has been a game-changer, offering an impressive balance of power and versatility. But what if you already have a 5.56/.223 AR-15 and want to convert to a .300 Blackout – enter the .300 Blackout upper receiver.

The .300 Blackout upper allows you to shoot .300 AAC rounds in your AR-15 platform by simply swapping out upper receivers. There are a lot of upper receivers out there, which is why we went out and tested a plethora of 300 uppers to find the best five money can buy.

We also thought it wise to include some benefits of using a 300 Blackout upper instead of other calibers, as well as what factors you should consider when buying an upper. Enjoy the read!

300 Blackout Upper Receiver Groups


What Is The 300 Blackout Upper Receiver?

The 300 Blackout upper receiver is the upper part of AR-style rifles chambered for the .300 AAC Blackout cartridge. The upper receiver houses the barrel, handguard, bolt carrier group, and charging handle.


Are 300 Blackout Uppers Compatible With AR-15 Rifles?

300 Blackout Uppers are compatible with AR-15 rifles. It is designed to fit seamlessly onto standard AR-15 lower receivers. If you have an AR-15 chambered in another caliber, like the .223/5.56 NATO, you can quickly swap out your existing upper receiver with a 300 Blackout upper receiver. This basically means you can turn your existing rifle into one that fires .300 AAC rounds.


Best 300 Blackout Upper Receivers

Here are the best 300 Blackout Upper receivers we tested.

  1. Aero Precision M4E1 16in .300 Blackout Barrel Complete Upper Receiver
  2. BRN-180SH SUPPRESSOR OPTIMIZED 300 BLACKOUT 10″ UPPER RECEIVER
  3. Radical Firearms .300 AAC Blackout Upper Assembly
  4. PSA .300 Blackout Uppers
  5. Jacob Grey Firearms Ultralight 300 BO Complete Upper
Lasso Brag

1. Aero Precision M4E1 16in .300 Blackout Barrel Complete Upper Receiver

Editors #1 Pick
Aero Precision M4E1 16in .300 Blackout Barrel Complete Upper
4.9

Includes: 19% Off Plus Blazin' Deal w/ Free S&H

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The Aero Precision M4E1 is a product of decades-long experience in manufacturing quality MIL-SPEC parts. It boasts a durable 7075-T6 aluminum design and is further enhanced with M4 feed ramps and a hard coat Type III MIL-SPEC coating.

Furthermore, the Aero Precision has a one-piece free-floating handguard to ensure better accuracy. It has a barrel length of 16 inches with a twist rate of 1:7. It also comes with an A2 flash hider.

Aero Precision M4E1

It is important to note that the M4E1 does not include a bolt carrier group or charging handle. Nonetheless, this upper receiver is a true embodiment of a value-packed .300 Blackout offering precision and reliability.


2. BRN-180SH SUPPRESSOR OPTIMIZED 300 BLACKOUT 10″ UPPER RECEIVER

Runner Up
BRN-180SH 300 BLACKOUT
4.7
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A unique piece by Brownell, this upper receiver has been fine-tuned for suppressor use. I am a huge fan of the new gas shutoff setting, coupled with the adjustable charging handle, which enables me to reduce noise considerably.

This upper is designed to fit any standard AR-15 spec lower receiver. It offers a gas system that is easy to adjust and maintain. The barrel is a 10.5″ nitride one with a 1:8 twist, so this is the upper to get if you want a quiet, short-barreled rifle.

BRN-180SH


3. Radical Firearms .300 AAC Blackout Upper Assembly

Radical Firearms .300 AAC Blackout Upper Assembly
4.5

Includes: $19.95 Off w/ Free S&H

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Radical Firearms upper assembly is designed to be an easy drop-in solution for any Mil-Spec AR-15 lower. It offers a full suite of features like a forward assist, A2 flash hider, adjustable gas block, ejection port, and a free-float handguard.

Built for law-enforcement standards, this upper receiver is a fine blend of quality and affordability, and its 16-inch barrel is more than adept at shooting tight groupings. Overall, if you want a versatile upper receiver that won’t break the bank, you should opt for our budget-friendly pick of this list.


4. PSA .300 Blackout Uppers

PSA .300 Blackout Uppers
4.3
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Palmetto State Arms has a vast selection of .300 Blackout Uppers. Still, my favorite has to be the 16-inch barrel with a 1:8 twist rate – I just feel more comfortable with this barrel length as opposed to a short barrel version, especially when target shooting.

Its Chrome Moly vanadium 4150V barrel just resonates with quality and durability. Plus, the 15″ PSA lightweight M-Lok handguard allows for various accessory adjustments. The PSA .300 Blackout includes an A2 flash hider, BCG, and charging handle- talk about value!


5. Jacob Grey Firearms Ultralight 300 BO Complete Upper

Jacob Grey Firearms Ultralight 300 BO Complete Upper
3.0

Includes: 50% Off After Instant Savings w/ Free S&H

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Although not as popular, the Jacob Grey 300 Blackout upper is a testament to modern design principles. It’s built with a focus on shaving off unnecessary weight without compromising strength and durability. I was amazed by how light it felt – at a mere 7.7 ounces, it weighs less than some 300 Blackout scopes! There are various barrel lengths to choose from, ranging between 8″ to 16″.

This upper receiver is crafted from billet 7075-T6 aerospace aluminum. Also, it comes with the JG-designed free float 7-sided M-LOK handguard – providing ample mounting space for your optics and other accessories.

If you’re looking for something different, the Jacob Grey is the upper receiver for you!


Which Is The Best Suppressor Ready 300 Blk Upper?

The best suppressor-ready 300 Blackout upper is the BRN-180SH suppressor by Brownells. With features like a gas shutoff setting, this upper receiver provides optimal performance when combined with a suppressor, allowing you to reap the full benefits of a quiet 300 Blackout upper receiver.


What Are The Benefits Of Using A 300 Blackout Upper Receiver?

There are many benefits of using a 300 Blackout upper instead of other AR-15 calibers, such as versatility, power, suppressor-friendliness, and adaptability.

  • Versatility: Compatible with standard AR-15 magazines, the 300 BLK AR-15 upper receiver allows easy transition between calibers.
  • Power: Provides a punch similar to the 7.62x39mm, but with a shorter cartridge. This makes it adept for various use cases, such as varminting, hunting, self-defense, and tactical use.
  • Suppressor Friendly: Designed to work effectively with suppressors, providing quieter operations.
  • Adaptability: Efficiently cycles both super and subsonic ammo without modifications.

What Factors Should Be Considered Before Buying A 300 Blackout Upper?

Before buying a 300 BLK upper, consider factors such as material, barrel length, handguard compatibility, muzzle device, and budget.

When buying, look for uppers made from durable and lightweight materials like 7075-T6 aluminum. This type of material provides incredible durability without adding too much weight to your AR build.

Handguards are important as they determine your mounting compatibility (M-LOK, Keymod, Picattiny) with optics and other attachments. It also affects accuracy and performance due to its influence on the barrel and overall weight of the AR-15, respectively.

Your budget is arguably the most important factor to consider before buying a 300 Blackout upper. Quality comes at a cost, but it doesn’t mean that quality 300 BLK uppers are inaccessible if you are on a tight budget. Take the Radical Firearms 300 upper; it only costs $310 yet is one of the best uppers you can buy. Determine a budget, but ensure you don’t compromise on essential features. Many of these factors should also be considered before buying one of the 5 Best AR-15 piston uppers as well.

Barrel length is another crucial factor to look at. Your use case often determines the barrel length and twist rate you should get.


How Does Barrel Length Affect The Upper Receiver Group?

Barrel length impacts the velocity, accuracy, maneuverability, and weight of your AR-15 upper receiver group. When deciding what AR-15 barrel length you want, consider how the length affects the factors mentioned in the previous sentence.

You want a short AR-15 barrel for short range, allowing better maneuverability and reduced weight. On the other hand, if you want a long-range 300 BLK upper offering better accuracy and velocity, you need a barrel that’s either 14 or 16 inches.


Are All Handguards Compatible With 300 Blackout Upper Receiver Groups?

Not all handguards are compatible with the 300 Blackout upper receiver group. Therefore, when choosing between AR-15 handguards for your 300 Blackout upper, always ensure the handguard is long enough to cover the gas block but won’t extend beyond the muzzle.

Also, ensure the handguard’s mounting system matches the upper receiver to ensure a uniform and compatible mounting platform for your red dot sights and other attachments.


Can Red Dot Sights Be Mounted On 300 Blk Uppers?

Red dot sights can be mounted on 300 Blackout uppers. In fact, the 300 Blackout is one of the best platforms to mount an AR-15 red dot optic, as its ballistic characteristics make it ideal for close to medium-range shooting – distances a red dot is designed for.

When mounting a red dot sight, double-check the sight is compatible with your handguard and doesn’t obstruct your vision. Luckily, most upper receivers come with a flat-top Picatinny rail, allowing easy attachment of red dot sights.


Frequently Asked Questions

Do 300 Blk Uppers Improve AR15 Performance?

Yes, 300 Blackout uppers improve AR-15 performance. They offer better versatility, especially when switching between super and subsonic rounds, and are more suited for a suppressor.

Do Your AR-15s Need To Be Modified To Install 300 Blackout Upper Receivers?

No, you do not need to modify your AR-15 to install 300 Blackout uppers. An upper-chambered 300 Blackout is designed to be compatible with standard AR-15 lowers.

The Bottom Line

The 300 Blackout upper receivers offer gun enthusiasts a balance of power, versatility, and adaptability over traditional .223/5.56 NATO uppers. When choosing the right upper for your AR-15, consider your primary use, be it hunting, target shooting, or self-defense. Always make sure your individual parts are compatible. Few things are as frustrating as waiting weeks for a new handguard only to find out it is incompatible with your upper receiver. Ultimately, with the right choice and compatibility, your AR-15 can be a powerhouse in any scenario.

About the author

Charles Neser

I'm a life long hunter & gun lover. Currently pursuing my Master's Degree (M.Sc.) in Animal Nutrition at University of the Free State.

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