The 300 Blackout is a versatile round which was introduced in the market to impart an AR-15 with the power of a 308 caliber rifle. This round is widely used for hunting because of its proper balance of weight, ballistics, size, and economics between the 5.56 and 308.
Switching from a 5.56 AR-15 to a 300 Blk AR-15 just requires the change of an upper and the barrel. However, there are still certain aspects that need to be considered before buying one.
Here we’ll learn about such factors and the perks of upgrading to a 300 Blk upper receiver. We will also review five of the best 300 Blackout upper receivers on the market to help you with your buying decision. So keep your eyes pinned and your fingers scrolling.
At a Glance: Our Top Picks for 300 Blackout Uppers
Comparison Chart of the Best 300 Blackout Uppers
Our Top Pick
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Uppers 101 - Parts Overview
The upper receiver, also known as ‘upper’ in short is practically a half portion of an AR-15. The upper is comprised of the most important parts of the rifle, which perform all important tasks. The upper receiver includes the action, barrel, handguard (with or without rails), and the sights.
The action of an upper receiver includes the chamber/breech and the bolt carrier group. It is responsible for loading, ejection, and firing of the cartridge. Actions are caliber specific to some portions. A 300 Blackout rifle uses the bolt carrier group of a 5.56 AR but it has a differently designed chamber specific to the shape of the cartridge. Loading otherwise can lead to serious or even fatal malfunctions.
Next comes the barrel. It is specific to the caliber you are shooting. The 300 Blackout rifles use barrels specifically designed for the caliber. Barrels can have different types of contours, rifling, and twist rates. So you should choose an appropriate one depending upon the ammo, grain, aesthetics, and your intended purpose.
Other than these, an upper receiver features the handguard. There are many different kinds of handguards available for the AR platform. Including M-Lok, Key Mod, Classic, etc. Handguards can have rails on them to mount extra accessories and scopes. Some uppers also include back-up iron sights.
Aspects to Consider Before Buying
While reading this review, you must consider certain aspects and characteristics of a 300 Blackout upper receiver.
Uppers are generally made from high quality aircraft grade aluminum. However, they can be manufactured using different methods which include forging, billet machining, and casting.
Forged upper receivers are considered to be the most durable of all, however, they will be denser and heavier.
Cast receivers are lightweight but offer the least amount of strength.
Billet receivers fall somewhere between these two on strength and weight.
Stripped or Complete
A stripped upper receiver is just a machined block with no components installed, so you have to buy them separately. However, this gives you room for customization.
Complete uppers, on the other hand, contain all the accessories and can be installed and used right away. Since they include all the components, they are economically more viable. This review includes only complete receivers, so you won’t have to search for individual components. Plus, most people like to change only a part or two in their uppers.
If you are buying a complete upper receiver, you should take a serious look at the length, rifling, profile, and twist rate of the barrel. Longer barrels are good for long range hunting, whereas shorter ones are for tactical and competitive uses. Similarly, the weight and velocity (sub or supersonic) of the ammunition must also be taken into consideration.
Handguard and Top
Uppers can either have flat tops or carry handles. Plus, the handguard can either be simple or have a mounting pattern. All the uppers reviewed here have tactical handguards with flat tops and rails for better customization options.
Review of the Best 300 Blackout Uppers
Considering the aspects mentioned above, we have come up with the best 300 Blackout Uppers in the market. All these receivers are complete and ready to fire instantly.
PSA 16" Pistol-Length 300AAC Blackout 1/8 Nitride 15"
This is a complete upper receiver which has been forged using 7075 T6 aluminum for durability. It is an M4 type receiver which includes a forward assist, BCG, handguard, and barrel. The BCG has been made from shot-peened 158 carpenter steel and features a full auto profile for rugged use. It also includes a nitride coating for resistance to wear and tear. It has a low profile pistol-length gas block which is ideal for 300 AAC rounds.
Moving to the front, the upper has a Chrome Moly Vanadium 4150V barrel chambered for 300 AAC. With a 1:8 twist rate, the barrel can handle both subsonic and supersonic rounds really well. The heavy profile of the barrel allows you to shoot continuous rounds without any issues. The barrel features a nitride finish and the muzzle has 5/8-24 threads to accept suppressors and muzzle brakes.
The barrel already includes an A2 flash hider. The upper also features a PSA 15" lightweight, M-Lok rail, partial Picatinny rail, free-float handguard, which doesn’t touch the barrel and hence doesn’t disturb its harmonics. The 16-inch barrel is long enough to let you take distant shots with precision. This complete upper is available at an exceptional price and is quite versatile for overall use.
The PSA 16-inch upper receiver is a ready to fire addition to your lower receiver. Its barrel length makes it versatile and the inexpensive price adds to its viability.
PSA 16" Pistol-Length 300AAC Blackout 1/8 Nitride 13.5"
This is another very durable, feature-packed, and inexpensive complete upper receiver from PSA. It has been forged from 7075 T6 aluminum and features a pistol length gas system to handle both super and subsonic ammunition, also coupled with a low profile gas block.
It features a 16-inch 4150V Chrome Moly Vanadium barrel with a nitride finish and ⅝-24 threading which accepts most suppressors and muzzle brakes. The 1:8 twist rate of the barrel is quite versatile and ideal for handling multiple kinds of operations.
The extra feature with this complete upper receiver is the Magpul backup iron sights. These sights can be folded down when not needed and can also be removed with ease. The sights can be used in conjunction with optic scopes for better performance.
The flat top receiver has a Picatinny rail for mounting scopes. The handguard has M-Lok slots which allow you to install slings and other compatible accessories over your weapon. It includes a full-auto bolt carrier group for rigorous use under all circumstances.
This complete upper includes back up iron sights along with all other components and an M-Lok free-floating handguard. All within an affordable and fair price.
Best for the Money:
PSA 10.5" Pistol-Length 300AAC Blackout 1/8 Nitride 12"
What could be better than having a 300 Blackout rifle? Having one at almost half the price. Even if you have to assemble it. This kit from Palmetto is a complete disassembly setup of a 300 Blackout rifle.
The kit not only includes the complete upper receiver but all the other parts to let you successfully complete the weapon, except for the lower receiver which has to be bought separately. The upper features a pistol-length gas system with an A2 profile barrel having a twist rate of 1:8 inches. The receiver has been forged from aluminum and is durable enough to withstand the test of time. It also features a slanted end, 12-inch M-Lok handguard with rail.
The muzzle of the barrel includes a fluted cash can which can be easily removed to reveal ⅝-24 inch threads for mounting a muzzle brake or suppressor. The lower parts kit includes a fixed stock, pistol grip, buffer tube, and all other components to assemble the rifle.
This is a complete kit which almost completes your rifle at an unbelievable price. The short barreled rifle is compact and ideal for tactical uses.
4. PSA 8.5" 300AAC Blackout 1/7 Nitride 2A Armament 10"
Looking for an SBR or pistol rifle? This short barreled upper is your answer. The receiver is forged from aluminum and hard coat anodized to resist wear and tear. The barrel length is 8.5 inches and has an exceptional twist rate of 1:7 inches.
The barrel can handle supersonic rounds with extreme accuracy and precision. It also has a nitride finish and lining so it doesn’t accumulate much grime and requires less maintenance. The full-auto profile BCG has been made from carpenter 158 steel and runs very smoothly.
The upper can be mounted on a pistol lower. However, if you want to mount it over a regular rifle-sized lower, you’ll have to overcome certain legal implications. The barrel has a flash can threaded over the muzzle. Plus, the upper features a full-length rail from the receiver to the tip of the handguard. The M-Lok handguard can also be used to mount slings and other compatible accessories.
This is a pistol-length upper which an amazing twist rate for accuracy. The weapon is appropriate for competitions and short range hunting.
5. Brownells - AR-15 Assembled Upper Receiver Keymod
This is an exclusive AR-15 upper made from Brownells. This 300 Blackout upper receiver contains a 16-inch 1:8 twist barrel. The A3 13-slot aluminum flat top receiver is standard and includes a 10” handguard, utilizing the KeyMod rail system.
It has a phosphate finish to withstand corrosion and dirt. Plus, it also assists with cleaning. This is an A3 style upper which will attach to almost any compatible AR-15 lower receiver. The handguard features Keymod holes across its length, where each of these holes can be used for QD accessories.
It also helps both aluminum and P-mag magazines cycle really well. The upper is exceptionally good for hunting and practice and is surely a good deal for its price.
The Brownells upper receiver is a good piece of equipment with respect to its price and construction. The upper doesn’t include a BCG and charging handle, so you can customize and add your own.
Perks of Upgrading Your Upper
The very first benefit of upgrading your upper receiver is the tactical advantage. You are most likely to upgrade your receiver if you are changing the caliber or want a complete package of all its components. A properly equipped upper receiver has the right construction, ergonomics, and accessories to offer you a tactical advantage under difficult situations.
Secondly, upgrading to a complete upper receiver saves you a lot of money and effort, which would otherwise have been spent in selecting individual parts.
Upgrading just your upper receiver assembly lets you keep your existing lower you are comfortable with.
A 300 Blackout rifle requires a specific upper receiver which can be mounted on an AR-15 lower receiver while using the same BCG. A complete upper receiver is basically comprised of the BCG, chamber, ejection port, handguard, barrel, and sights.
Before buying a receiver, you must consider its construction quality, type (complete or stripped), barrel (if complete), and the top. Choosing the right upper is optimal for your accuracy and overall performance with the weapon.