At a Glance: The top AR 15 uppers
- OUR TOP PICK: Primary Weapons Systems AR-15 MK111 MOD1-M Upper Receiver
- TOP RATED: Foxtrot Mike Products Ar-15 Fm-45 Complete Upper Receivers
- BEST BUDGET OPTION: Aero Precision M4E1-T ATLAS R-one complete upper 5.56
Comparison of The Best AR-15 Uppers
Our Top Pick
|Primary Weapons Systems AR-15 MK111 MOD1-M Upper Receiver
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|Foxtrot Mike Products Ar-15 Fm-45 Complete Upper Receivers
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BEST BUDGET OPTION
|Aero Precision M4E1-T ATLAS R-one complete upper 5.56
|View Latest Price
Guide To The Best AR-15 Upper Receivers Reviewed
If you’re looking into buying a new AR-15 upper you’ll find that there are a lot of them on the market. You want to make sure you buy exactly what you want so we did extensive research to help you find “the one.” As with everything in life, you’ll have to determine what your priorities are in an AR-15 upper. Any shooter wants an upper that is durable, accurate, can be used for home defense, and that is not crazy expensive. Most shooters are willing to spend extra for quality.
Primary Weapons Systems AR-15 MK111 MOD1-M Upper Receiver
The MK1 MOD 1-M line features a long-stroke piston system. That means a long metal piston is physically attached to the bolt carrier.
- Color: Black
- Finish: Matte
- Caliber: .223 Wylde
- Barrel Length: 11.85 in
- Free-float MLOK handguard
When the gun fires, the gas pressure acts on the front of that long shaft and those gasses force the piston backward. It has the benefit of delivering the most reliable power to the action. It features a free-float MLOK handguard which provides for better accuracy and mounting points. It also has a forward assist. The MK1 MOD 1-M line is suitable for civilians as well as law enforcement. It is forged which provides for a great durability, but could add on weight.
- 3-setting adjustable gas system
- Includes Radian Raptor Charging Handle
- A mid-length gas system which allows for versatility (long-range/home-defense)
- Free-floating M-LOK 7.1″ Handguard (1.8″ width, 2.1″ height) is included
- Very light: 3 lb. 8 oz.
- Higher-end of the price range
Foxtrot Mike Products Ar-15 Fm-45 Complete Upper Receivers
The Foxtrot Mike .45 ACP Upper Receiver comes fully assembled. This is a complete Flattop Upper for Pistol Caliber AR-15 Carbines that uses Glock magazines. The 8.5”, 10.5”, and 16” upper receivers use an ambidextrous non-reciprocating forward charging handle. While the 5” upper receiver utilizes a standard AR style rear mount charging handle.
- Cartridge: 9 mm Luger
- Length: 5″
- Muzzle: 5/8-24
- Twist: 1-10
- Bolt/carrier unit with hard Melonite finish
With its full-length Picatinny top rail and M-LOK compatible handguard, the Foxtrot Mike .45 ACP upper offers a good amount of space for optics and other accessories. The barrels of these AR15 Upper Receivers are constructed with 4150 chrome moly steel for reliable durability.
- Fully assembled
- Pistol caliber lower compatible
- Free float M-LOK handguard
- Made out Chromoly, very cheap, light, highly accurate
- Made in USA
- Charging handle does not fold
- Glock mags may swell which consistently causes failures to feed and lock open
- Not compatible with Korean magazines or aluminum cased ammunition
Aero Precision M4E1-T ATLAS R-one Complete Upper Receivers
Looking for the best AR upper for the money? Aero Precision M4E1 is a nice and sturdy Complete Upper Receiver. It is forged for durability. However, forging adds weight. The carbine gas length makes it perfect for home defense.
- Barrel Length: 16 in
- Barrel Profile: Fluted
- Handguard Length: 15 in
- Gun Rail: M-LOK
- Muzzle Device: A2 Flash hider
- 1:8 twist rate
It is fully assembled which allows for easy installation. However, it does not include a bolt carrier group or charging handle. Those have to be bought separately. On the plus side, it includes a muzzle brake which lowers the recoil by around 50%.
- Forged, so durable
- ATLAS R-ONE free-float handguard included
- M4 Feed ramps
- Carbine length gas tube
- Laser engraved T-marks make it look sexy
- Includes port door and forward assist
- Bolt carrier group and charging handle are not included which makes it more expensive at the end
Primary Weapons Systems MK111 PRO Upper Receiver
The MK111 PRO upper features an 11.85″ barrel, which is a great length for a variety of uses from pig hunting to home defense. You can fit it on any standard AR-15 lower. The handguard is included. It is not forged but made out of extruded aluminum. Also, it does not include a forward assist and it can be quite loud when shooting.
- Barrel length: 11.85″
- .223 Wylde chamber
- Piston System: Carbine
- 6061 Extruded aluminum upper
- Cartridge: 223 Wylde
- Twist: 1-8
- The recoil impulse is mild
- Free-float MLOK handguard included
- Upper fits great with any AR-15 lowers
- Great value for the buck – above medium price range
- Very smooth cycling
- Great modularity
- No forward assist
- Looks plain
- Quite loud
Radical Firearms AR-15 16″ Upper Assembly 5.56
The Radical Firearms 16″ M4 upper receiver is a flat top, law-enforcement grade, drop in receiver, ready to be mounted to any Mil-Spec AR-15 lower receiver. It is a very affordable upper. It comes assembled with a forward assist, ejection port door, barrel nut, 16″ M4 profile barrel, and A2 flash hider. It is a great option especially for the beginner or budget-minded shooter. The handguard and bolt carrier group have to be bought separately which will add to the price.
- Made out Chromoly, cheap, light, high accuracy
- 1 in 7″ twist rate
- 5.56 NATO Chamber
- M4 Feed ramps
- Carbine Length Gas System
- Radical Firearms 15″ FHR Hybrid Rail System
- Possibly some quality issues with loose screws
- Bolt Carrier Group and Charging Handle not included
BRN-180S AR-15 Complete Upper Receiver
The Brownell’s BRN-180S Complete Upper Receiver is inspired by the 1960s Armalite AR-180. The BRN-180S is shorter than the standard BRN-180. The barrel is only 10.5 inches long. The free float M-LOK handguard is also shorter. The BRN-180S gas piston is adjustable from the front making the switch to suppressor use quick and easy. One great feature is the .223 Wylde chamber which makes it safe to shoot 5.56 NATO and .223.
- Cartridge: 223 Wylde
- Length: 10.5″
- Muzzle: 1/2-28
- Style: Complete
- Twist: 1-8
- Compatible with current mil-spec AR-15 lowers
- Free float handguard
- Machined and Lightweight: only 4 lbs
- Low maintenance
- No tools needed to take the handguard off
- Gas piston is adjustable
- If you shoot your AR-15 fast, the handguard can get hot quickly.
- supporting hand can get blackened from the gas
- Super loud
- Higher-end price range
What Is An AR-15 Upper?
The upper is easily the second most important part of building your AR-15, after the barrel. An AR-15 upper receiver (or just upper) is only half of an AR-15 receiver. The other half is the lower receiver.
|Assembled Upper Receiver Includes:
|Lower receiver includes:
|Bolt carrier group
|And all other necessary components
Uppers have not changed much throughout the history of the AR-15. The first models had a carrying handle with an integrated sight that disappeared with the popularity of optics. The types and designation of the AR-15 uppers depend on which stage of the evolution of the platform they adhere to. For Stripped Upper Receivers you will need to purchase additional components and an upper parts kit which include:
- A forward assist that helps seat rounds and resolve jams.
- A dust cover keeps debris and dirt from entering the action. Although not necessary, they are nice to have to keep the gun functioning reliably.
Stripped Upper or Assemble Upper – Which Should You Buy?
The beauty of the AR-15 is its modularity and the interchangeability of its parts. The only component which is registered and sold as a gun is the lower receiver. You can have only one lower and multiple uppers that go with it. Officially, you own only one gun but have many to play with (this is what I love about the AR-15). However, you have to make sure those uppers fit well with the lower as that is an essential part of building a reliable gun.
Building your AR-15 could be also a money-wise decision. When you get all the required pieces and spend countless hours building it yourself that means you did’nt have to pay somebody to do that. The money you save can go towards another gun. On the other hand, when you get better at building AR-15s you’ll want higher-end parts for it and they ain’t cheap (story of my life, bro).
You will also learn a lot by building a gun. It will give you an amazing sense of pride. But a word of advice before you decide to build your AR-15: Make sure to figure out what you expect from it and how often you will use it before you set out.
How to assemble an AR-15 upper receiver
Since you have decided to build your AR-15 why not assemble your AR-15 upper receiver yourself as well? Again, you will acquire a great understanding of your gun and bolster your ego at the same time.
If you don’t buy a pre-assembled upper, there are two options to follow. You can either buy an AR-15 upper assembly kit or buy all the necessary pieces separately. However, if you have never built any gun before you might want to go with the assembly kit which will ensure that all the pieces fit together. Also make sure that you have all the necessary tools to do the job including a bench vice, armor wrench, a receiver block, and a barrel nut wrench.
The steps to assemble your AR-15 upper are as follows:
- Install the AR-15 upper forward assist. The forward assist will be properly lined up when you can see daylight through the hole. The bare AR-15 upper will usually come with the forward assist pre-installed together with the ejection port door.
- Set up the AR-15 dust cover. This might be hard due to the spring. The spring has to exert pressure on the dust cover but can’t block the way while the rifle is firing. Insert half of the retaining rod with the dust cover on the gun and then position the spring with the retaining rod.
- Install the AR-15 barrel. You have to screw it in with the just-right amount of torque. The wrong amount of torque will undermine the accuracy of the gun. The reaction rod will help you with this step.
- The AR-15 barrel nut will couple the barrel with the upper receiver and host the handguard. Again, do not over-torque it.
- The gas tube goes on next. It directs hot gasses out of the barrel to the gas key at the bolt carrier group. That is the source of the energy for powering the action.
- Install the handguard.
Types of AR15 uppers: A1 to A4
There are four different types of AR-15 uppers. Although they each have their particular features, the most obvious difference is whether there is a fixed carrying handle or not.
- The AR-15 A1 upper is the original version that was developed in the 1960s. It was used by soldiers in the Vietnam War as the M-16 A1 rifle. It features a light profile barrel, a forward assist, a fixed carry handle, and a triangular-shaped handguard. There is also a flip rear sight to adjust for windage and short- and long-range apertures. This type of AR-15 upper is great for up to 450 yards shooting accuracy.
- The AR-15 A2 upper is an upgraded version of the A1 from the early 1980s. It is still equipped with a forward assist and a fixed carry handle. However, the rear sight is adjustable for not only windage but also elevation (up to 600 yards). The barrel is heavier and handguards are rounded.
- The AR-15 A3 upper introduced a detachable carrying handle. Depending on the manufacturer, it may be equipped with either Picatinny or Weaver rail to mount scopes. Some A3 models have a high-rise configuration providing for a higher sope positioning. It also features a forward assist (A Picatinny rail is included on the following models: the BRN-180S AR-15 complete upper and the Foxtrot Mike Products AR-15 FM-45 complete upper).
- The AR-15 A4 upper is also a flat-top upper receiver similar to the A3 model. The A4 also includes M4-style feed ramps like the Aero Precision M4E1-T ATLAS R-one complete upper and the Radical Firearms AR-15 16″ assembled upper).
Parts of an AR-15 Upper and What They Do
|Protects your hand from the barrel’s heat so you can enjoy a comfortable shooting experience. Also lets you support the weapon with your non-dominant hand.
|The most important piece of the upper receiver. Besides your skill, It plays the main role in your shooting accuracy.
|Required for your rifle to cycle. Gas pressure forces the bolt carrier group backward which ejects the used round and puts a new one in the chamber every time you pull the trigger. The gas travels behind the bullet and enters the gas system through the gas port on the gas block. Gas blocks are installed on the barrel, inside the handguard.
|Bolt Carrier Group
|Responsible for chambering and igniting rounds, assuring bullets are fired correctly, and ejecting used rounds from the chamber. It includes multiple components.
|The part that pulls your bolt carrier group to the rear when you want to load the first round into the chamber or need to clear a malfunction. In case one round does not fire as expected, you can simply release the faulty shell and reload a new one with the help of the charging handle. While firing your AR-15, the charging handle remains stationary.
|Enhances your AR-15 reliability. Should your bolt not close for some reason, hitting the forward assist can seat the round so that it can. Some AR-15 owners do not find it necessary. I like it though. It is included in all reviewed models except for the PWS MK111 Pro upper.
|Ejection Port Cover
|Help keep your AR-15 clean. Its function is to protect the bolt carrier group and upper receiver from dirt, dust, and other debris when it is closed. It opens up automatically when the bolt carrier group moves back.
|Supposed to keep brass out of the face of the shooter, especially if he or she is left-handed.
|Components that enhance your shooting experience and live on your rifle’s muzzle. These include:
After researching, reviewing, and comparing the above-mentioned AR-15 uppers, we can establish the following criteria for the best upper:
- Quality has to be high.
- Forged AR-15 upper receivers are more durable than machined ones.
- Carbine gas system and barrel length are more suitable for home defense (compared to a rifle which is more for long-range).
- Free-floating handguards are generally a better option for accuracy.
- .223 WYLDE chambering is a good way to safely fire both 5.56 NATO and .223.