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The AR-15 rifles are equipped with upper and lower receivers, usually crafted from heated aluminum (forged one). The AR15 upper is a simplified name of the upper receiver, which is necessary to protect urgent AR15 parts.

Best AR 15 Upper - Editor's Choice

This review will show you the differences between uppers, which are necessary to be aware of in order to properly build an AR15.

Why do we need an AR 15 upper?

All parts of the AR15 rifle are interconnected. If you forget to put even a small detail, the whole unit won’t work at all. If you want to improve the accuracy, the upper receiver will help even more than the lower one, because the fired bullet or the loaded round operates in the upper receiver. The completed rifle weight and general performance are affected by the upper as well.

 

Best AR 15 Upper | AR 15 Upper Reviews

ImageProductBrand
Aero Precision M4E1 5.56 Mid Barrel Complete Upper ReceiverAero PrecisionBUY
Luth-AR AR-15 11.5in Lightweight Complete AR 15 Upper Barrel AssemblyLuth-ARBUY
TRYBE Defense AR-15 16in Complete Upper M-LOK, .300 BLK UPPERTRYBE DefenseBUY
Wilson Combat Billet AR 15 Upper ReceiverWilson CombatBUY
TRYBE Defense AR-15 Lightweight M-LOK Handguard with Full RailTRYBE DefenseBUY
V Seven Weapon Systems - AR-15 Upper Receiver Lithium AluminumV Seven Weapon SystemsBUY
Aero Precision AR15 5.56 Complete Upper ReceiverAero PrecisionBUY
SLR-B15 Billet Upper 5.56 Receiver SLRB-15-UPP 556SLR-B15BUY
Stag Arms AR-15 A3 Flattop Upper Receiver AssemblyStag ArmsBUY
TRYBE Defense AR-15 16in Complete Upper M-LOK, .223 WyldeTRYBE DefenseBUY
ODIN Works INC. - AR-15 Billet Upper ReceiverODIN WorksBUY
Dark Hour Defense AR15 Billet Upper Receiver DHUPPDark Hour DefenseBUY
Precision Reflex AR-15 Flat Top Upper ReceiversPrecision ReflexBUY
Aero Precision M4E1 16in 5.56mm M4 Carbine Barrel Complete Upper ReceiverAero PrecisionBUY
TRYBE Defense AR-15 Pistol 10.5in Complete Upper M-LOK, .300 BlackoutTRYBE DefenseBUY

#1 Aero Precision M4E1 5.56 Mid Barrel Complete Upper Receiver

Aero Precision M4E1 5.56 Mid Barrel Complete Upper Receiver

Specification

Caliber: 5.56x45mm NATO
Barrel Length: 16 in

This Upper is outfitted with feed ramp extension, anti-rotation tabs, constant top rail, scalloped rails, and improved milling construction for better gripping and visual attractiveness. The Upper Receiver Handguard Combo with Gen 2 improved handguard is designed for AR-15 A2 Flash hider and should be placed on the M-LOK Picatinny Rail. This barrel is listed as a mid-length one and is a government profile. The reinforced upper locks tightly into the typical M4E1 lower without wobbling. A BCG or charging handle doesn’t come with the upper kit.

Pros:
  • Fast disconnect sling sockets;
  • Pre-assembled: matches with Lantac bolt;
  • A new Picatinny top-rail profile;
  • High-quality build;
  • The durable finish on the Cerakote;
  • Awesome price;
  • Robust construction, but quite light;
  • No burrs on the barrel, Nitriding is smooth and shiny;
  • Everything is tightened down duly.
Cons:
  • The FDE color doesn’t match Magpul: Aero’s is browner, whereas Magpul’s is more greenish in hue;
  • The rails aren’t as long as expected: there’s not enough space to run a foregrip a bit closer to the magazine or a bipod with a foregrip.

#2 Luth-AR AR-15 11.5in Lightweight Complete AR 15 Upper Barrel Assembly

Luth-AR AR-15 11.5in Lightweight Complete AR 15 Upper Barrel Assembly

Specification

Caliber: 5.56x45mm NATO
Barrel Length: 11.5 in
Threaded Barrel – Thread Pitch 1/2 x 28

Lightweight barrels are crafted from Chrome Moly Vanadium (4150) with 6 Lands and Grooves, a 1–9-inch RH Barrel twist joined to an A3 Flattop receiver, which comes with a charging handle, bolt carrier, ejection port cover, and forward assist. The upper is topped off with a low-profile gas system (.750 diameter Gas Block and Carbine-length Gas Tube), 9-inch Palm Handguard with a Picatinny top rail, and KeyMod slots.

Pros:
  • Durable machining;
  • Solid AR assembling;
  • M4 Feed Ramp;
  • Broached Button.
Cons:
  • None yet.

#3 TRYBE Defense AR-15 16in Complete Upper M-LOK, .300 BLK UPPER

TRYBE Defense AR-15 16in Complete Upper M-LOK, .300 BLK UPPER

Specification

Caliber: .300 AAC Blackout
Overall Length: 16 in

This versatile Complete Upper comes with everything (a bolt carrier group, a 15-inch M-LOK Freefloat Rail, 5R Rifling, an A2 Flash Hider, a 1:8 inch Twist, Mil-spec Charging handle, Nitride BCG) to install straight to a lower receiver and it’s ready for shooting. This 4140 CMV black Anodized Nitride barrel shows good results in groupings out to 75 yards with about 1.25 in MOA among groups.

Pros:
  • Fits perfectly Bushmaster lower receiver;
  • Limited lifetime warranty;
  • BCG and charging handle are included;
  • The handguard has tabs, in case it comes loose it won’t spin on the shooter;
  • The flat black color without sine;
  • Awesome handguard design.
Cons:
  • The charging handle is a bit cheap;
  • The upper receiver powder coating leaves marks on any surface it touches;
  • California’s Proposition 65.

#4 Wilson Combat Billet AR 15 Upper Receiver

Wilson Combat Billet AR 15 Upper Receiver

Specification

Caliber: 5.56x45mm NATO; .458 SOCOM
Gun Make: AR Platform; Wilson Combat

This upper is a next-generation precision tactical firing platform, which matches well with Wilson BILLet-AR lower receivers, standard Mil-Spec forged AR-15 GI lowers or and any standard AR barrels. It is outfitted with a Picatinny top rail, shell deflector, a precise undersized bolt raceway for smoother chambering, tougher receiver walls to minimize shooting flexibility. This upper is CNC machined from aerospace aluminum (7075-T6) billet stock, covered with Mil-Spec hard-anodized black. The 458 SOCOM cartridge is appropriate for hunting medium to large game, bullets in the 250 – 400 grain weight range feature huge killing power.

Pros:
  • Enhanced feeding and recoil dynamics;
  • The ability of gas volume adjustment allows fining tune of carbine’s bolt velocity for a specific load’s power;
  • The smooth side profile without forward-assist for maximum accuracy;
  • Useful in pair with a heavy barrel, added thickness provides less flex and more barrel support;
  • Minor machining of the upper receiver ejection port opening delivers clearance for the larger cartridge.
Cons:
  • None yet.

#5 TRYBE Defense AR-15 Lightweight M-LOK Handguard with Full Rail

TRYBE Defense AR-15 Lightweight M-LOK Handguard with Full Rail

Specification

Handguard Length: 7 in; 9 in; 12 in; 15 in.

The handguards are equipped with a full-length Picatinny rail on the top for secure mounting scopes, red dots, and other optics, coming with mounting screws and a barrel nut. The TRYBE Defense crafted these AR-15 Lightweight M-LOK Handguards from sturdy aluminum (6061-T6). There are eight models with 4 options of handguard length, available in Flat Dark Earth and Black colors.

Pros:
  • Made in the USA;
  • Adds minimal weight to the build;
  • Lightweight, but sturdy;
  • Limited lifetime warranty;
  • The top Picatinny rail is ready for fixing sights as-is, it’s M-LOK as well;
  • The barrel nut is easy to install;
  • Cerakote finish is flawless;
  • The guard sits flush with the top rail.
Cons:
  • No Torx wrench;
  • Сalifornia’s Proposition 65.

#6 V Seven Weapon Systems – AR-15 Upper Receiver Lithium Aluminum

V Seven Weapon Systems - AR-15 Upper Receiver Lithium Aluminum

Specification

Caliber: 5.56x45mm NATO
Style: Striped
Weight: 5.8 oz

The Ar-15 Upper Receiver is crafted from an advanced alloy of Lithium and Aluminum (billet 2055) with Hardcoat Anodized (type Iii). Enlightened 2055 Upper should be Minor fitted to the Upper rail to be compatible with Geissele Mk8 Rails. It’s recommended to lubricate all installed Springs, Pins, Screws, and parts with quality oil or grease.

Pros:
  • Lithium/Aluminum is lighter, more sturdy, better resistant to corrosion than standard Aluminum (7075 T6);
  • Superlight;
  • High-quality: tolerances are tight as they should be.
Cons:
  • None yet.

#7 Aero Precision AR15 5.56 Complete Upper Receiver

Aero Precision AR15 5.56 Complete Upper Receiver

Specification

Caliber: 5.56x45mm NATO
Barrel Length: 7.5 in; 10.5 in; 11.5 in; 16 in.
Handguard Length: 7 in; 9 in; 9 in; 15 in.

The Complete Upper Receiver is combined with the ATLAS handguard allowing the AR15 build to be more modern and lightweight due to the Forward Assist removing. This upper receiver with M-LOK mount type is equipped with Mid-Length Barrel and A2 Flash Hider.

Pros:
  • No Forward Assist;
  • Helps reduce assembly weight;
  • Durable finish;
  • Good tolerances.
Cons:
  • None yet.

#8 SLR-B15 Billet Upper 5.56 Receiver SLRB-15-UPP 556

SLR-B15 Billet Upper 5.56 Receiver SLRB-15-UPP 556

Specification

Caliber: 5.56x45mm NATO
Weight: 7.6 oz

The SLR offers Upper Receiver with Mil-Spec dimensions and Mil-Spec Hard Coat of Type 3. These uppers are made of Aluminum Alloy (7075 Billet) with Matte Black Finish. The assembly comes with Black Billet Shell Deflector and Door installation.

Pros:
  • Awesome design with the octagonal geometry of the receiver and rail;
  • High-quality machining.
Cons:
  • The handguard doesn’t sit flush with the receiver and rail.

#9 Stag Arms AR-15 A3 Flattop Upper Receiver Assembly

Stag Arms AR-15 A3 Flattop Upper Receiver Assembly

Specification

Caliber: .300 AAC Blackout

The Stag Arms developed A3 Flattop Upper Receiver with dust cover and installed forward assist for mounting on the Picatinny Rail of the AR Platforms. This Assembly is forged with Black hard-coat anodizing (type 3), complying with mil-spec standards.

Pros:
  • ARs option of uppers for left-handed;
  • Well-made and reliable;
  • No issues while putting the rifle together;
  • Holds up just fine.
Cons:
  • California’s Proposition 65.

#10 TRYBE Defense AR-15 16in Complete Upper M-LOK, .223 Wylde

TRYBE Defense AR-15 16in Complete Upper M-LOK, .223 Wylde

Specification

Caliber: 5.56x45mm NATO, .223 Wylde, .223 Remington
Overall Length: 16 in
Barrel Twist Rate: 1-8

This AR-15 Mid-Length complete upper is outfitted with a 15-in M-LOK Freefloat Rail, Mil-spec Charging handle, an A2 Flash Hider, barrel with 5R Rifling, and a 1:8-in Twist. The upper receiver barrel is made of Stainless Steel (416R) with a Black Nitride BCG finish.

Pros:
  • Made in the USA;
  • Limited lifetime warranty;
  • Looks stylish;
  • BCG works flawlessly;
  • Affordable 223 Wylde.
Cons:
  • California’s Proposition 65;
  • A little bit sharp edges at the handguard base, which can be easy to fix;
  • The upper doesn’t drop completely into the lower receiver, so you either have to drill/mill out the rear channel on the lower or return the upper assembly;
  • One of the gas key screws isn’t securely staked;
  • The barrel/chamber with some scratching.

#11 ODIN Works INC. – AR-15 Billet Upper Receiver

ODIN Works INC. - AR-15 Billet Upper Receiver

Specification

Caliber: 223 Remington, 5.56 mm NATO
Style: Striped

The Odin, taking into account modern trends, reduced weight and bulk to make the rifle building with Billet Upper Receiver sleeker and thinner for convenient carry still delivering great performance. These uppers are equipped with a trimmed-down brass deflector.

Pros:
  • Streamlined convenient design;
  • Trimmed away the forward assist;
  • Minimalistic construction: no internal parts- you can stuff your AR-15 according to your needs.
Cons:
  • None yet.

#12 Dark Hour Defense AR15 Billet Upper Receiver DHUPP

Dark Hour Defense AR15 Billet Upper Receiver DHUPP

These Upper receivers are outfitted with a 1913 top rail and extended feed ramps, designed for AR15 platforms to ensure durability and accuracy. The uppers are manufactured from Aluminum (7075 T6 Billet), covered with mil-spec hard-coat anodizing (Type 3), with Dark Hour Defense logo.

Pros:
  • Modern Billet style;
  • Looks great paired with a STNGR handguard: the horizontal contour lines match up perfectly;
  • The finish color is a nice deep black;
  • Good machining and design.
Cons:
  • While installing the door port, it doesn’t lock, it’s out of spec;
  • The logo isn’t lasered as advertised;
  • The area forward of the ejection port and behind the barrel nut is not Mil-Spec dimensions.

#13 Precision Reflex AR-15 Flat Top Upper Receivers

Precision Reflex AR-15 Flat Top Upper Receivers

Specification

Caliber: 5.56x45mm NATO
Style: Striped

AR15 Flat Top uppers are crafted of forged aluminum (7075 T6) with Black Hard Coat Anodized, complying with Mil-spec standards. This upper receiver is equipped with forward assist and dust cover.

Pros:
  • Nice design.
Cons:
  • Too loose and sloppy;
  • Don’t fit any of 3 different lower receivers.

#14 Aero Precision M4E1 16in 5.56mm M4 Carbine Barrel Complete Upper Receiver

Aero Precision M4E1 16in 5.56mm M4 Carbine Barrel Complete Upper Receiver

Specification

Caliber: 5.56x45mm NATO, .223 Remington
Handguard Length: 12 in; 15 in
Barrel Length: 16 in

The Aero Precision engineered M4E1 Complete Upper receiver with Scalloped Rails, Anti-Rotation Tabs, continual Top Rail, and Feed Ramp Extension, but without BCG and Charging Handle.

Pros:
  • Quality craftsmanship;
  • Improved upper with integrated handguard;
  • Durable and excellent quality product;
  • Much room for optics, lights, and hand stops;
  • Reduced overall weight;
  • Simple handguard removal: just take off 8 tiny screws.
Cons:
  • None yet.

#15 TRYBE Defense AR-15 Pistol 10.5in Complete Upper M-LOK, .300 Blackout

TRYBE Defense AR-15 Pistol 10.5in Complete Upper M-LOK, .300 Blackout

Specification

Caliber: .300 AAC Blackout
Overall Length: 10.5 in

This upper barrel is made of 4140 CMV, covered with Black Nitride BCG. The AR-15 complete upper receivers are equipped with an A2 Flash Hider, a bolt carrier groupб a 10.5-in M-LOK Free Float Rail, a Mil-spec Charging handle, a barrel with 5R Rifling, and a 1:8-in Twist.

Pros:
  • Made in the USA;
  • Limited lifetime warranty.
Cons:
  • California’s Proposition 65;
  • Unknown Materials: there is no indication of what the handguard is made of;
  • The gas block is not pinned;
  • The tolerance between the barrel nut and the handguard is poor: the tightening screws should be over-torqued just to hold it in place.

How to Build an AR-15 Upper Receiver

An armorer’s wrench or the barrel nut wrench (for a proprietary foregrip), a vice, a torque wrench, some grease, and a little Loctite (for the barrel nut) will be necessary.

Brief instructions:

  • Install the barrel in the upper receiver, thread on the barrel nut onto the upper, and tighten down to 35-65 ft-pds.
  • Then fix the gas block and tube assembly slide the handguard over the barrel nut (Loctite gives added grip of the barrel nut with the knurled surface).
  • Align the rail with the receiver and put the mounting screws in the drilled holes, tightening them down to 50 pounds.
  • The installation for an assembled receiver will be quicker than a striped one (no need to install the forward assist and ejection port cover).

AR-15 assembled Upper Receiver Build

  • A barrel nut for the gas tube alignment tabs and a set screw-based gas block are included.
  • Before tightening the handguard up, check the gas tube coming out straight.
  • Thread the barrel nut on before the gas block allows for handguard tightening.
  • Some barrels are dimpled, which is convenient to pair them up with a set screw kind of gas block instead of the clamp one as we do in stripped receiver mounting.
  • After tightening the holes with the two included rods the handguard stayed put.
  • It’s recommended to use a screwdriver through the larger ports or use straight edges for a wrench.

Stripped receiver mounting

  • First, an upper receiver should be placed into the vice block and take the two pieces of the forward assist -FA (its tooth should be faced in towards the receiver), duly orienting them and start the roll pin with a punch. It’s possible to use the hammer softly, tapping in the pin enough so the FA cannot come out.
  • Then fix the ejection port. The pin should have installed the C-shaped snap ring. Otherwise, be attentive not to lose this small part while installing it.
  • Before twisting the spring 180 degrees, put the ejection port, slide the hinge pin. Then push the rod through in the empty area.
  • Mount the barrel with the oiled index pin, fitting into the receiver, and place the nut onto the barrel.
  • The proper seating between the handguard surfaces procedure depends on setting the torque to 35 ft-lb and loosening, doing in this way a few times in a row.
  • If you have a new handguard, a gas tube alignment isn’t required, but older versions of many handguards do (the gas tube should fit on straight both with the gas block and into the barrel nut index “U”).
  • Get the gas block and gas tube out. Start the roll pin, finishing it. Slide on the gas tube over the barrel, use a .025 in space to move the block back for the best fit.
  • Set the wheeler torque wrench to 35 in-lb (or according to the gas block instructions) to make the torque even.
  • Install handguard mounting hardware, fitting it to the receiver, align duly, the indexing pin should be completely flush at the bottom near the screws.
  • It’s better to use a crush washer and its smaller side should be towards the barrel.
  • Align both top holes and the big ports on the side to vent the gases majority to the side and some to the top to counter muzzle rise.
  • The last step is to lube up the charging handle and BCG.

FAQ

Can you put any AR upper on any lower?
The combination of different brands of upper and lower receivers doesn’t influence the shooting accuracy. The lower with stock can be put to a rifle upper.

What parts do I need to build an AR-15 Upper?
The upper receiver, to which the barrel and the forend are fixed, is outfitted with the bolt carrier group, charging handle, receiver frame, dust covers, and forward assist. Uppers are usually forged or fully machined and come with attachment rails for accessories.
Do AR-15 uppers require FFL?
You can buy AR15 upper parts or upper assemblies online without FFL (Federal Firearms License) or a background check, it’s not required. The upper quantity is not limited.
What is the most important part of an AR-15?
The bolt is the most important AR part, which is a high wear one, that’s why for overall rifle good operation it should be high-quality. Other parts even in a bad state (a non-mil-spec buffer tube, low-quality barrel, or poor finish) don’t have such influence on general rifle functionality.
What is included in a complete upper receiver?
A completed AR-15 upper includes the ejection port door and the forward assist button installed. Complete upper assemblies come with the barrel, charging handle, handguard, and often with the bolt carrier group.

What part of an AR-15 requires a background check?
A background check should be submitted if you purchase a firearm. The serialized lower receiver is interpreted by the BATFE as the “firearm” portion of an AR is to go through a licensed FFL (dealer or gun store). The other parts such as the Upper Receiver, the Barrel Assembly, the Bolt Carrier Group, and the Stock don’t need background checks.

Conclusion

There are two builds, which differ in a way of barrel, gas blocks, and handguard mounting: a striped one, which comes with forward assist and ejection port cover, and the assembled one. The second build is an SPR (special purpose rifle) that delivers more accuracy, meanwhile, the first one provides weight and speed. The longer the barrel, the more the round’s velocity. The intermediate length (between middle and rifle) ensures a softer shot, and the reliable chamber gives more accuracy.

The Best Pick

Aero Precision M4E1 16in 5.56mm M4 Carbine Barrel Complete Upper Receiver

View on OpticsPlanet

This improved upper with integrated handguard features quality craftsmanship and plenty of room for optics, lights, and hand stops.

Budget Pick

Wilson Combat Billet Upper Receiver

View on OpticsPlanet

The upper provides enhanced feeding and recoil dynamics, the ability of gas volume adjustment, and maximum accuracy due to the smooth side profile without forward-assist.

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